BULLETIN #31


Electronic edition, please read.


Table of contents/Table des matières

Cover Page

Review Article

Latest News on Instrumentation

Recent Technical Activities

Scientific News

Directors' Corner

Observing Statistics and Observing Schedule for the next semester (1994II)

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Cover Page

IMAGE OF FROSTY LEO WITH ADAPTIVE OPTICS

NDLR: It was impossible to get a electronic version of the cover image.

COVER CAPTION: Near infrared image of IRAS 09371+1212 also called "Frosty Leo nebula". This color composite was made out of exposures taken at three different wavelengths, 1.65 micron, 1.28 micron, and 0.85 micron. Red, green, and blue colors have been matched so that the longest wavelength appears in red and shorter wavelength in blue. North is on the top. East on the left.

Data were taken at the 3.6m Canada-France-Hawaii telescope with an experimental adaptive optics system developed at the University of Hawaii. The system compensates wave-front distortions produced by atmospheric turbulence. The circle in the upper right corner has a diameter of 0.5 arcsec, which is about the diameter of uncompensated stellar images when data were taken. Wave-front compensation has improved the angular resolution by a factor five down to the diffraction limit of the telescope in the near infrared.

The central object appears to be a multiple source with components aligned in the plane of the disk. It is seen through a thick circumstellar disk and is heavily reddened. The upper and lower lobes of this bipolar nebula are illuminated by the central source and reflects light at shorter wavelengths.

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REVIEW ARTICLE


Spectro-imagerie avec BEAR dans la bande K' des nébuleuses planétaires AFGL 2688 et NGC 7027

Il est aujourd'hui reconnu qu'une large fraction de nébuleuses planétaires possède des enveloppes de gaz moléculaire. Ces enveloppes ont été détectées dans les raie ro-vibrationnelles de l'hydrogène moléculaire (H2) et dans les transitions millimétriques de CO (Huggins et al., 1994). Les conditions physiques du gaz neutre associé aux nébuleuses planétaires sont clairement liées aux processus qui ont determiné l'évolution des enveloppes. L'enveloppe moléculaire éjectée lors de la phase géante rouge est exposée dans la phase nébuleuse planétaire au champ de rayonnement ultraviolet extrèmement intense de l'étoile centrale (de cent un million de fois le champ de rayonnement du milieu interstellaire) tout en étant soumis aux effets de compression et de fragmentation induits par ionisation et par les vents stellaires. La compréhension théorique des conditions extrêmes de ces milieux de photodissociation ainsi que de leur dynamique est encore élémentaire (Tielens, 1993). En particulier, la transition rapide qui définit le passage de la phase dite branche asymptotique géante (AGB) à la phase nébuleuse planétaire est assez mal connue. Ceci est dû au fait que les processus physiques les plus importants ont lieu dans les régions les plus enfouies et donc les plus obscurcies de l'enveloppe moléculaire. Des observations directes de ces zones internes, généralement petites (de l'ordre de 10 secondes d'arc) sont essentielles afin de contraindre et améliorer les modèles existants et doivent être effectuées avec la meilleure résolution spatiale possible, à des longueurs d'onde peu sensibles aux effets d'extinction.

Nous rapportons ici les premiers résultats obtenus à l'aide de l'instrument BEAR, dans le cadre d'un programme qui a pour but d'étudier en détail les conditions physiques associées aux régions les plus internes des enveloppes moléculaires de nébuleuses proto-planétaires et des nébuleuses planétaires. BEAR a déjà fait l'objet d'un rapport dans un précédent numéro du bulletin du CFHT (No 29, 2ième sem. 1993) et nous ne rappelerons que brièvement ses principales caractéristiques. C'est le nom donné à la combinaison de deux instruments CFH, le Spectromètre par Transformée de Fourier (FTS) et la caméra infrarouge Redeye, construite autour d'une mosaique de 256x256 pixels de type NICMOS. Au lieu du spectre d'un seul point source comme dans le mode standard, ce mode permet d'obtenir pour une source étendue, en chaque point du champ d'environ 24 secondes d'arc, le spectre correspondant. Le champ est échantillonné avec une échelle de 0,33''/pixel. Pour une qualité d'image typique de 2 pixels à mi-hauteur, c'est plus de 750 spectres indépendants qui sont obtenus simultanément. Le domaine spectral peut être choisi où l'on veut dans le domaine de longueur d'onde entre 1 et 2.5 m. BEAR permet un choix de résolutions spectrales continues, depuis très bas jusqu'à 10E4. A partir du cube formé par tous les spectres, des images monochromatiques de l'objet peuvent être constituées, permettant une véritable spectroscopie à 3 dimensions. Pour le programme ci-dessus nous avons choisi la bande K' (1,95 - 2,30 ) riche en raies de l'hydrogène moléculaire et en raies du gaz ionisé - hydrogène et hélium. Les résultats qui sont décrits ont été obtenus fin octobre 1993 et se rapportent à la proto-nébuleuse planétaire AFGL 2688 et à la nébuleuse planétaire NGC 7027.

AFGL 2688 ("Egg nebula", dans la constellation du Cygne) est l'une des rares sources connues actuellement en transition entre la phase AGB et la phase nébuleuse planétaire. Depuis sa premié&re description par Ney et al. (1975), AFGL 2688 à été l'objet d'un grand nombre d'études tant observationnelles que théoriques (voir Latter et al., 1993 et références citées). Particulièrement brillante en infrarouge, AFGL 2688 est une nébuleuse bipolaire avec deux lobes brillants diffusant la lumière de l'étoile centrale froide (type F5, Teff = 6500 K). La morphologie visible et proche infrarouge est reproduite de façon convaincante par le modèle de Yusef-Zadeh et al. (1984) dans lequel le tore équatorial se trouve dans un plan Est-Ouest et l'axe bipolaire est aligné dans la direction Nord-Sud le long de la nébuleuse par réflection. La Figure 2 montre l'image monochromatique (corrigée du continuum) obtenue avec BEAR dans la raie ro-vibrationnelle 1-0 S(1) de l'hydrogène moléculaire en direction de AFGL 2688. L'émission H2 montre quatre petits globules brillants ayant une distribution cruciforme très remarquable. Les spectres de ces globules sont de purs spectres d'hydrogène moléculaire sans la moindre trace de gaz ionisé (aucune présence de Br-gamma qui se trouve dans le domaine couvert par le filtre utilisé). Une émission H2 à faible niveau relie les structures Nord et Est, ainsi que les structures Sud et Ouest. Les globules individuels sont légèrement allongés. L'émission de l'hydrogène moléculaire est absente des parties les plus centrales de la nébuleuse et, en particulier, il n'y a pas d'émission H2 dans la direction Est-Ouest, là où se trouve probablement le tore équatorial. L'émission du continuum dans la bande K' (lumière réfléchie par les grains de poussière) est surtout détectée entre les globules Nord et Sud. Une analyse des spectres de l'hydrogène moléculaire suggère que le mécanisme d'émission devrait être dominé par une excitation par chocs.

NGC 7027 est une source charnière dans l'étude des nébuleuses planétaires. Il s'agit en effet d'un objet relativement jeune émettant intensément dans les raies moléculaires millimétriques (CO et autres) où les régions internes de l'enveloppe ont été ionisées par le rayonnement de l'étoile centrale extrèmement chaude (Teff = 2 x 10E5 K) pour former une région HII compacte alors que les régions extérieures sont encore relativement intactes et sous forme moléculaire. Les caractéristiques de l'enveloppe neutre ont été étudiées en détail par de nombreux auteurs (Jaminet et al. 1991). NGC 7027 a aussi été l'objet d'observations dans les domaines proche infrarouge et radio avec des résolutions spatiales de l'ordre de la seconde d'arc et en deça (Graham et al., 1993; Roelfsema et al., 1992).

L'image dans la transition 1-0 S(1) de l'hydrogène moléculaire en direction de NGC 7027 obtenue avec BEAR est présentée dans la Figure 2. L'hydrogène moléculaire possède une morphologie extérieure fort proche de celle d'un trèfle à quatre feuilles entourant une structure centrale, sorte d'anneau parfait. Cette structure interne est sans aucun doute le tore équatorial de NGC 7027 vu ici pour la première fois en son intégrité. L'étoile ionisante (non visible) se trouve probablement en son centre. Les régions internes à la bordure déssinée par les boucles de l'hydrogène moléculaire sont ionisées et clairement détectées dans les raies de Br-gamma , HeI, et HeII. L'hydrogène moléculaire est le plus intense dans le tore équatorial et dans les parties Nord-Est et Sud-Ouest des boucles extérieures. La morphologie générale de l'hydrogène moléculaire est remarquablement similaire à celle observée dans la transition millimétrique (1-0) de la molécule HCO+ qui trace les régions chaudes et de haute densité (106 cm-3) entre le gaz ionisé de la cavité centrale et l'enveloppe de gaz neutre tracée dans les transitions rotationelles millimétriques de CO. Enfin les raies de l'hydrogène moléculaire détectées et cartographiées dans NGC 7027 par BEAR montrent que l'intensité des raies de H2 sont compatibles avec une excitation induite par le rayonnement ultraviolet caractérisant la région de photodissociation.

Les différences dans la morphologie et l'excitation de l'hydrogène moléculaire observées dans AFGL 2688 et NGC 7027 sont les reflets de leurs stades d'évolution où:

  1. AFGL 2688 représente la phase proto-planétaire durant laquelle des vents stellaires rapides (100 km/s) rencontrent l'enveloppe éjectée dans la phase AGB - qui se propage à une vitesse plus lente (20 km/s) - développant ainsi des chocs intenses capables d'exciter l'hydrogène moléculaire.
  2. NGC 7027, le paradigme des nébuleuses planétaires jeunes, où l'intense champ de rayonnement de l'étoile centrale ionise les régions les plus internes de l'enveloppe AGB et excite l'hydrogène moléculaire dans les zones de photodissociation en bordure de la région HII et des surfaces moléculaires de l'enveloppe extérieure.
En conclusion, les résultats brièvement évoqués ci-dessus démontrent le grand intérêon;t que peuvent avoir des observations dans le proche infrarouge effectuées à haute résolution spatiale et spectrale dans l'étude des nébuleuses planétaires. A ce point de vue, BEAR se révèle un instrument idéal pour étudier la morphologie, les conditions d'excitation, la cinématique de l'hydrogène moléculaire et des espèces ionisées, ce que ne permettent pas les autres méthodes de spectro-imagerie. Avec plus d'observations de ce type il sera possible de suivre tous ces éléments dans leurs rapports au degré d'évolution rapide entre les phases AGB et l'apparition des nébuleuses planétaires.

Pierre Cox 
Observatoire de Marseille
Jean-Pierre Maillard  
Institut d'Astrophysique de Paris

Références

Figures Captions

Figure 2: Images monochromatiques obtenues avec BEAR dans la raie 1-0 S(1) de l'hydrogène moléculaire à 4712.9 cm-1 en direction de la nébuleuse proto-planétaire AFGL 2688 et de la nébuleuse planétaire NGC 7027. L'émission due au continuum a été soustraite de ces images.

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Latest News on Instrumentation


SIS Guiding Efficiency and Software Upgrades

The needs for improvement

The limiting magnitude for active guiding with the SIS mirror was found insufficient in the old version of the system. The best performance with the photomultiplier optical unit was no better than V = 16 (see Information Bulletin No. 30), which would prevent the use of active guiding on a significant portion of high galactic latitude fields. The new proposed system uses avalanche photo-diodes and is expected to allow guiding on stars as faint as V = 18.5.

This new system was delivered and integrated at CFHT in March; it was tested during 4 engineering nights: 31 March-01 April and 16-17 April, then briefly documented and released to observers in April-May after some software improvements.

Performances

limiting magnitude

Active guiding is possible on a star with R = 18.4 (V ~ 19) with an integration time 0.2 s, but this is an extreme limit. In the Pegasus "SIS guider" window, the total count for the 4 detectors is listed for 1 sec integration (independently of the actual integration time used for guiding). For such a star, the flux is 600 counts/sec above the sky and the sky level was 2800 counts/sec. We deduce a Signal/Noise ratio 2.3 per channel in 0.2 sec.

More reliable guiding can be performed on stars brighter than V = 18.5 and we thus conclude that the system behaves as expected. The guiding frequency can be increased, up to 100 Hz, for increasing brightness.

offsets and stability

One step for the displacement of the SIS guide probe is 0.054" on the sky, while one 15 pixel of the CCD represents 0.087". The mapping between the CCD and the guide probe coordinates has been done and the area accessible to the guide probe is between X=(-470,3100) and Y=(0,2500) expressed in CCD coordinates. It is thus possible to guide with the probe slightly outside the (2048x2048) CCD area by using the offset function.

The SIS offset can be used for small and very precise displacements (centering the objects in the slits, for instance) without losing guiding.

The flexures between the guide probe and the detector are very small: less than 0.1" per hour. It was possible to make long spectroscopic exposures with a 0.35" (4 pixels) slit without need to recenter.

resolution improvement and PSF

The seeing was good during the engineering nights. Typically, the 0.6" resolution with bonnette guiding was improved to 0.5" with SIS guiding. We did not see a clear dependance of the resolution improvement with the guiding frequency, nor with the distance to the guiding star. These effects should exist, theoretically, but would show up only after statistics on a large set of data.

At 0.5" resolution level, the best concentration of light seems to correspond to slightly elongated images (probable residual astigmatism from the optics of the telescope, or of SIS, or both). Also, the PSF is not perfectly constant across the field.

Conclusion

The performances of the new SIS guiding system are satisfactory. It can be used routinely for multi-spectroscopy as well as imagery. More tests will be done during the next engineering night in July. Some residual problems (e.g.: difficulties for properly locking the active guiding in about 10% of the cases) will also, hopefully, be fixed.

C. Vanderriest, B. Grundseth

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PUEO Progress Report

The Adaptive Optics Bonnette has definitely left the stage of project, and entered the phase of "instrument". Progress are recorded by the hour!

Dominion Astrophysical Observatory has completed all the mechanics and electronics. All the optics has been received. However, this statement requires some qualifications. It is often at the time of delivery that problems occur. The f/20 camera mirror of the Bonnette turned out to have the wrong figure. SORL had fabricated an excellent mirror but with the wrong specifications. After numerous tests at DAO the error was found and the mirror was shipped back to SORL, where a new one is now in fabrication. Delivery is now expected for the end of June. The test rig is completed for the various reproducibility and flexure tests, and the more compact mount for the cold tests as well.

When the micro-lens array was received in last February, defects were seen in the gluing of the external ring of lenses, and it was decided that it would be send back to OPTEC in Italy for repair. In mid-May when back in DAO, (apparently it was stuck in customs for most of the time), it was noticed that there was an unacceptable 15 degrees rotation between the outer and inner ring of lenses. Furthermore, the focus of the lenses is inside glass, making interfacing with the APD optical fibers impossible. It has been shipped back again, and it is not known when delivery will take place, or what kind of repair is going to be done by OPTEC.

Applied Physics Specialty was late to produce the beamsplitter but experienced problems also at the time of depositing the semi-reflecting coatings. They did not succeed to produce the 45-45 % transmission-reflection asked for. They used a aluminum coating (30-30 %) which is very inefficient but will be used for tests only.

All the other optical components are received and, at this stage, perform as expected. CFHT has been forced to develop a high-quality f/3 to f/20 beam converter in order to adapt the CFHT phase-shift interferometer to the AO Bonnette. These optics have been designed and fabricated and were delivered to DAO along with the interferometer in May.

On the mechanical aspect of PUEO, the most important concern has been the performance of the wavefront sensor. This extremely complex module is mounted on a X,Y,Z stage that moves to focus and pick up the reference source wherever it is in the 90 arcsec field. The precision of this motion and its stability as well must be excellent in order to insure a good image quality during observation. Given the numerous components mounted on the X,Y,Z stage, their weight (remember that a optical transfer system had to be added for pupil and field viewing), flexures and reproducibility of positioning of the device has led DAO to explore the implementation of counterweights and also the stiffening of the mount. This has caused some delays in the completion of the WFS assembly.

On June 11, the first round of acceptance tests took place at DAO. It has concentrated on flexures, stability and reproducibility of the mechanics, and also acceptance of the control system of PUEO. In the next issue of this Bulletin we will report in more detail about the results of these tests. Our first impression is that the instrument is very robust, motors driving the various slides have plenty of reserve power, which has been confirmed by driving them against gravity, at 20 and 0C. Two more rounds of tests are planned in DAO, basically for the electronics, and optical quality testing.

Laserdot is experiencing a short delay in the completion of the bimorph deformable mirror. The mirrors (CFHT receives a hot spare also) have been fabricated and have been replicated. They have been delivered to Laserdot (an outside company makes the replication) and the interferogram show that they have an outstanding surface quality. The aging process of the mirrors has started. Laserdot prepares itself for the acceptance tests of their subsystems. These will essentially concentrate on the bimorph mirror quality testing. The final tests of Laserdot sub-systems will take place at the Observatoire de Paris-Meudon (OPM) next fall, where integration will take place.

OPM is also getting ready for the integration and test phase of the project. Detailed plans have been made and fabrication has started of the test rig, the telescope simulator and the turbulence generator. This took somewhat longer than planned given the restricted budgetary envelop and the non-trivial problem of producing the equivalent of a 3.6 m telescope diffraction-limited image.

The detailed definition of the control system software and the interactions between the AO Bonnette and other CFHT systems was established last summer. A final version of the definition document including updates developed this past year will be issued before system testing at Meudon this fall.

Coding of the control system software at Laserdot was completed earlier this year with the exception of a maintenance user interface which will be coded over a 6 week period starting in June. Although code tests have been carried out at Laserdot using dummy devices, the controllers, software, and AO mirror won't be tested in closed loop until this fall when subsystems will be integrated at Meudon with the mechanics from DAO.

CFHT graphical user interface is being developed at CFHT using its PEGASUS software system. Another software package, Data Views, is being used for displays of real-time signals and optical bench configuration. An initial interface definition has been established. A prototype of the interface running in a PEGASUS pseudo observing session has been developed and can be made available to those in the user community interested in seeing the details of what an AO Bonnette observing session might look like. Comments on its form and feel are welcome. Coding of the final product is to start in July.

In conclusion, the rest of the summer and the fall will be a very busy period for the CFH staff. Eight staff members will be involved in the various stages of acceptance tests for the AO Bonnette from now on to the winter 1995. Let's remember here that these tests have the benefits of finding out malfunctions in the instrument, and evaluating the final performance, but mostly, they provide an invaluable opportunity for CFHT staff to get acquainted with the instrument before its arrival at CFHT; furthermore, the contact with the designers and constructors is extremely helpful for a good understanding of the functioning and further exchanges for the follow-up and the commissioning of the instrument. There is an unanimous agreement that such tests were a capital ingredient in the success of MOS/SIS at CFHT.

R. Arsenault, F. Rigaut, D. Salmon, J.Kerr

Figures Captions

Figure 1:The first round of acceptance tests of the AO bonnette in DAO, Victoria. These tests concentrated on opto-mechanical devices, and control software.

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OASIS Status Report

Last March 28 an important INSU review took place in Lyon (France) to review the state of the project. The following 2 days were dedicated to exchanges and discussions between the OASIS team and CFH staff, about the development of the instrument, the design choices, level of collaboration and implementation of the guest instrument status.

The INSU experts group recommended the OASIS team to proceed rapidly in order to benefit from and unique window of opportunity which is having an integral field spectrograph on adaptively corrected images, before the 8-10 meter class telescopes come on-line. In order to reach this goal, one of the experts committee recommendation said that if going fast meant reducing the complexity of the instrument, leaving only the TIGER and imaging mode, that they would encourage the OASIS team to do so. However, it is still in the OASIS planning to have the other modes implemented. The complexity of OASIS comes from the necessity of having variable spatial sampling (AO variable PSF) and the addition of the imaging mode. A TIGER Spectrograph installed on PUEO imposes the above requirements which in turn drives the number and position of enlarger wheels in OASIS. The addition of other modes requires only the insertion of a fiber bundle (ARGUS) or a slit (long-slit mode) in the aperture wheel, instead of the micro-lens array for TIGER.

This decision is somewhat in conflict with what the CFHT SAC recommended. SAC had emphasized that priority should be given to the imaging, long-slit, ARGUS and scanning Fabry-Perot modes; that these should be given the status of guest instrument. At this stage the SAC decided to adopt a pragmatic approach. In the end, it is not unlikely at all, that OASIS will contain all the modes that visiting astronomers may wish for. The OASIS team increased the manpower dedicated to the fabrication of the instrument in order to respect the schedule deadlines.

Concerning the technical aspects of the instrument, many technical details were discussed to make sure of compatibility with CFHT environment. There has been no blatant incompatibility seen in the actual design, and non-standard designs often represent an innovative improvement. The OASIS team had already reacted to previous CFH comments, and some corrections or improvements had already been brought to the designs. The most critical aspects of OASIS that truly concern CFH are the length and moment of the instrument and the development of the user interface. Furthermore, the fact that the CFHT plans to adopt the G. Luppino dewars, imply a short cable length between the dewar and the GENIII controller (1 m long). This implies that the controller would have to be mounted on the instrument, which would increase the weight and moment even more. Alternative solutions are being studied at this point. The OASIS team is investigating with W. Grundmann of DAO what would be the consequences of such high moment on PUEO mechanics.

The scheme adopted by Lyon for the user interface was very innovative. However, it was not compatible with the actual standard. The exchanges led to a compromise between the two teams, and capabilities aimed at by the OASIS team could be implemented inside the framework of CFH's PEGASUS interface. Lyon clearly indicated that they would like CFHT software group to develop the user's interface for OASIS. Although this is a very reasonable approach (and by the way what CFH recommends in the IDS!) it is definitely not clear that CFH has the manpower nor the time for that. Possible solutions are being investigated.

Needless to say, this 3-days visit from CFH at Lyon Observatory was extremely fruitful. A good communication and spirit of collaboration at these early stages will only make easier the later commissioning of OASIS on Mauna Kea. CFHT clearly realizes the importance of this instrumental project, being the only spectrograph currently planned for use with the adaptive optics Bonnette.

R. Arsenault, R. Bacon

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MOCAM Status Report

The 4Kx4K mosaic of CCD developed by the Observatoire de Toulouse, the Dominion Astrophysical Observatory and the University of Hawaii with the help of CFHT is progressing fast. MOCAM has been requested at the telescope for the second semester of 1994, and is scheduled for this period. This will force CFH and Toulouse to work intensively until then.

DAO has been active in the first phases of the project namely in the tests and selection of the LORAL CCDs, the fabrication of the mechanical filter wheel and its control software. These steps have been completed, and all the hardware is now in the hands of the Toulouse team. G. Luppino from the Institute for Astronomy has fabricated the dewar, which has been delivered to Toulouse at the beginning of this year.

The MOCAM team in Toulouse has been very busy integrating the four 2Kx2K CCDs handling mode within the CFHT GENIII software, particularly the code optimization in order to have a readout time of the mosaic. Similar to a single 2Kx2K CCD (this is made possible by using 4 amplifiers read-out for MOCAM. CFHT has put to the disposal of Toulouse a SPARC station and a GENIII controller to develop the implementation of the 4-amplifiers simultaneous read- out and to operate MOCAM. The final software development step was the modification of the FOCAM Pegasus user interface. CFHT has done its best to help the Toulouse team to familiarize themselves with the GENIII system; numerous visits of engineers and technicians at CFHT, continuous dialogues and questions-answers from Toulouse to CFH. The processus was smooth but somewhat slow since CFH had not yet developed a clear plan for the multi- amplifier read-out in the GENIII system. Therefore, the way was unpaved for the MOCAM team.

But progress has been made and the SPARC station was able to read out a 4Kx4K simulated data flow at the beginning of March. Progress was slow on the utility board since this work was being done at CFH while this component was badly needed in Toulouse. A first version turned out to be defective and delayed Toulouse's progress, but this has been solved with a new version sent in April. The first 4Kx4K image was read out at the beginning of June. CFH plans a new release for the GENIII controller system to take place this summer. J.-P. Dupin (engineer responsible for MOCAM in Toulouse) will visit CFH to get acquainted with the particularities of this new release. This is with this version that MOCAM will be used late 1994 at the telescope to insure compatibility with CFH systems.

CFH's goal is to have acceptance tests carried out in Toulouse before MOCAM comes on the telescope. Therefore, a busy MOCAM schedule is to be expected this summer for CFH staff. First the acceptance tests need to be defined, and agreed upon by the MOCAM team and then carried out before the shipping of MOCAM to Hawaii.

The characteristics of MOCAM are:

  1. Thick uncoated LORAL 2 sides abuttable
  2. 4096 x 4096 pixels
  3. 15 /pixel
  4. Gap between CCD 500
  5. Read-out noise 10e-
  6. Read-out time 7 to 8 min.

R. Arsenault,Y. Mellier, J.C. Cuillandre,D. Crampton, R. Murowinski

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Bear Status Report

The imaging Fourier Transform Spectrometer, Bear, will gain in the first semester of 1995 the status of CFHT instrument. It will become available to the whole community of CFHT users. Bear has been described in some detail in the CFHT Information Bulletin No. 29. F. Rigaut and D. Bohlender have taken the scientific responsibility of this instrument, formerly a duty of D. Simons who left us for Gemini.

The data reduction is performed using a package developed by D. Simons which is being integrated into a more user friendly interface. Also widget tools to extract spectra and images from the processed data cube have been developed at CFHT.

F. Rigaut

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New Detectors for the FTS Arrive

Though the Fourier Transform Spectrometer (FTS) has been used almost exclusively for 1-5 micron spectroscopy over its 10 year lifetime at CFHT, the FTS was designed to operate well into the visible light regime. The interferometer has always been equipped with a beam-splitter that is capable of visible light applications, and the ultimate short wavelength limit of the interferometer stems from the silver coatings on its reflecting optics. The only reason the FTS has not been used regularly at submicron wavelengths has been the lack of commercially available hybrid photodiodes needed to make submicron observations feasible. This is finally about to change with the fabrication of new silicon and InGaAs photodiodes for the FTS by EG&G Electro-Optics. The new FTS detectors are hybrid devices that contain in a small hermetically sealed package a photodiode, thermo-electric cooler, and high-gain amplifier. As seen in Figure 3 the silicon devices provide good sensitivity from 0.5 to 0.9 micron, while the InGaAs devices are tuned for 0.9 to 1.6 micron observations. Thanks to the compact design of these hybrid detectors, they are coupled to the FTS detector wedge using light-weight aluminum mounts and commercial X-Y stages for optical alignment. Cooling to about -35 C is achieved with a simple flick of a switch in 30 seconds using TE controllers mounted near the detectors. This obviously provides for more convenient operation than the pumped-LN2 dewars needed by the standard InSb photometers. The new detectors are compatible with the existing FTS electronics, data acquisition, and reduction software, hence changing from the InSb to Si or InGaAs detectors is a fairly transparent procedure for FTS users and the CFHT technical staff. Currently 1" round filters are mounted in a simple threaded cell immediately in front of each detector and changing filters requires a few minutes of work on the 5th floor (no remote filter changes yet!). Prospective users should keep in mind that the entire FTS and RedEye infrared narrow band filter stock is tuned for 77 K operation, not the nominal 0 C that filters in new submicron mode are kept held at. This translates into significant band pass shifts and may necessitate new filters for many programs. Typically 0.015 in a ()/ 1% filter (see Chapter 4 of the RedEye manual).

While there are surely numerous applications for the new detectors, the unique niche that this new FTS mode will fill among Mauna Kea instruments will be ultra-high resolution visible spectroscopy (R10E5 to 10E6) and excellent sensitivity in what is an essentially untapped window from 0.9 to 1.1 micron. At the time of this report the new detectors are scheduled for their first on-sky sensitivity tests this summer and prospective users should contact Dave Bohlender or Scot McArthur at CFHT or Jean-Pierre Maillard at the IAP for further details. Finally, this project was jointly funded by the CFHT Corp. and the University of Hawaii's SEED Grant Program.

D. Simons, S. McArthur

Figures Captions

Figure 3: The relative responses for Si, InGaAs, and InSb are plotted. All curves have been normalized to a peak QE of 80% in this figure. Assuming the InGaAs detectors work up to the manufacturer's specifications, they will be the detector of choice for FTS J-band observations, as well as work out to 1.0 micron.

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Recent Technical Activities


Prime Focus Bonnette Upgrade

Through the months of November and December 1993 I was asked to investigate several failures within the Prime Focus Bonnette. During this time I encountered several problems in trying to get the bonnette up and running again. First and foremost, there are not any schematics for the bonnette. I tried to make do by digging through the wires. However, the many splices and poor workmanship caused my work to multiply as more wires and connections were broken or made intermittent. To get the bonnette functional again, many wires needed to be redone, the encoders "band-aided" together and several limit switches needed to be replaced. I then proposed to the directors and engineers to bring down the bonnette for some much needed refurbishment and repairs in January. The goal of this refurbishment was to make the bonnette more reliable and easier to service. It involved the replacement of connectors limit switches, and how they are triggered. Also, new encoders were put into the bonnette's XY stage. Finally, test cables were fabricated to allow testing of the bonnette outside of the cage on the fifth floor.

The bonnette requires three cables to operate. Two cables from the controller go to the bonnette. The third cable goes to the local control box mounted on the bonnette. Prior to this rebuild, the control box's connector and one of the bonnette's connectors had identical D-type connectors. This caused the cables to, at times, be accidently swapped causing fuses to blow and wasted time during check out. For this rebuild, Military Specification circular type connectors made to work in this type of cold harsh environment were put in place of the two bonnette connectors. The wiring of the bonnette was re-done as well with new wires. This will prevent unwanted errors in connecting the bonnette as well as increase reliability. And if for some reason someone needs to go into the bonnette for service, there will not be as high a likelihood of breaking wires or connections. Sub connections were included in this wiring scheme to aid in trouble shooting and replacement of parts if needed.

The XY stage has had a history of failures due to limit switch breakage. It would cause unwanted run away conditions of the stage. The stage was retrofitted with new switches running in a fail safe condition. This means that the switches are normally in a depressed configuration. At the end of travel, the limit switch is released. This safer condition ensures the stage cannot coast through and have the switch reactivated for any reason.

The old encoders found on the bonnette drove sine and cosine signals to conditioning circuitry, to drivers circuits and finally down to the computers. Two out of the three encoders available were found to be bad and not replaceable as they are no longer available. New encoders were acquired that contained the necessary signal drivers built in. The new encoders allowed the removal of much unneeded amplifying and conditioning circuitry. This makes check out and maintenance much easier and efficient.

Finally, test cables were fabricated for this and future use. These extension cables were built to run the bonnette on its cart on the 5th floor outside the Prime Focus Cage. This feature was never available before and required the bonnette to be tested or trouble shot on the telescope in the close confines of the cage. All of this work was completed in less then five months with the help of several hard working CFH personnel. The PFB has been operational on the telescope since 1 June and will remain on until the 28th of June. Special thanks to Bobby Song and Dan Sabin for their electrical and mechanical abilities to pull this task off ahead of schedule.

G. Matsushige

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Cassegrain Bonnette Control System Upgrade

In the CFHT Bulletin #29, I clarified the motivation for rebuilding the 13 year old Cassegrain Bonnette control system, and touched upon the design and performance specifications of the replacement system. Since then, Electronics Group technicians and engineers at CFHT, and UVic Co-Op student Mr. Mike Gladders have designed and implemented the new system as originally outlined, and are well into the integration phase with the bonnette off the telescope. As I presented to the SAC last November, we regretfully had to slip the integration schedule from December 1993, to June 1994, since CFHT suffered a severe manpower shortage with the departure of four technical staff members during the second semester of 1993. The bonnette, with it's new control system as described below briefly, is scheduled for final night time checkout on the nights of 27-28 June. Following these two nights of testing, the cassegrain bonnette will be back in use 80% of the total observing time for the remainder of 1994.

The final implementation of the control system consists of a dedicated three-axis digital servo control computer (Galil DMC- 740), a host computer (TCS computer or PC) connected to the controller through a serial link, and seven custom interface circuit cards. The host computer provides the user interface, and acts as the master to the control computer. The control computer executes motion commands and data request commands from the host, as well as continuously retains closed-loop servo control of the X,Y and Z axes independent of the host computer. All three servo loops have incremental encoders for instantaneous position feedback during a move, and absolute encoders for position referencing. In addition to controlling the servo axes, the control computer also positions the bonnette's central mirror, and the guider camera filter and neutral density wheels through an auxiliary I/O data bus. The entire control electronics reside within one enclosure that is mounted to the bonnette. Consolidation of electronics with the electro-mechanical components has drastically reduced the amount of cables and interconnects over the old system, which should lead to a more reliable and maintainable system.

S. McArthur

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New Tool for PSF Measuring

The on-line evaluation of CFHT images quality is done by the IQE tool. Until recently, this tool performed measurements of the image PSF Full-Width-at-Half-Maximum (FWHM) along x and y axes using linear interpolation of pixels located near the star's half-maximum. This method, although very fast thanks to its extreme simplicity, had the following major drawbacks: The new program for measuring PSF, now available as an option of the IQE tool, is free of the above deficiencies. The algorithm implemented is based upon two hypothesis. First, it assumes the PSF of a well-focused image to be well approximated, in its upper part, by a two-dimensional Gaussian profile. Second, it considers that the signal received in each pixel, I(m,n), is a Poisson process, that is, the variance of the noise is proportional to the local value of the intensity. Under these hypothesis, the maximum likelihood estimates of the PSF parameters --- major axis, minor axis, and position angle of its FWHM ellipse --- are the corresponding parameters of a Gaussian profile minimizing the quantity

			   Equation 1

where I(m,n) is the Gaussian model depending on seven parameters (two means, three parameters of the covariance matrix, amplitude and vertical shift --- background), denoted by the parameter vector , and the summation is done over all the pixels (m,n) within the area of validity of the Gaussian hypothesis, which is defined by the above `` convention''.

Since the model to fit is non-linear, the values of parameters minimizing (1) can be obtained only iteratively; moreover, good initial guesses of parameters must be provided to ensure (fast) convergence [1]. The initial guesses are obtained as follows.

Background determination. The original image is ``unrolled'' into a one-dimensional array (fig. 5a). Since the test star is not located on the image edge, the beginning of the array is more likely to contain background pixels. The array is then examined pixel by pixel: if the current pixel is too far from the current value of the background mean (the confidence interval being determined by the current value of the background standard deviation times an exponentially decreasing weighting function), it is rejected; otherwise, the estimates of the mean and the variance are updated. The obtained estimate of the mean is then improved by calculating the histogram of the values within a 5-sigma interval about the mean; the centroid of the histogram bins above the histogram minimum yields a better estimate of the mean. This method is very robust even for highly contaminated images.

Spatial means are determined as centroids of the values above the background mean.

Covariance matrix determination. The first estimates of the matrix members are found as second moments of centered variables over the whole image, :

where is the background mean. These estimates are highly biased, since the real PSF has ``wings'' compared to a perfect Gaussian. However, the matrix defined by (2) - (4) is almost proportional to that of the optimal Gaussian; consequently, better estimates are obtained by optimizing a one-parameter model within the area .

Amplitude determination is direct since the model is linear in this parameter.

The optimization of these initial guesses is performed by the standard Levenberg-Marquardt method [2]. However, in 60% of the cases the precision requirements are found to be already satisfied by initial solutions, which makes it possible to avoid the final optimization.

The tests carried out on simulated Gaussian profiles as well as on actual stellar images have shown the good precision of the program, especially for very narrow PSF, where the IQE tool and other techniques [3] are less accurate. Also, the method is less sensitive to the noise and errors in the background determination. The main drawback of the program is its model-dependence, which means that for essentially non-Gaussian PSF one may expect more biased results; this disadvantage may be corrected, however, by increasing the number of parameters (one may parametrize the power in the exponential, for instance), the rest of the algorithm remaining the same.

A more thorough analysis of the question and a detailed description of the method and its implementation may be found in Boutenko (1994).

V. Boutenko, B. Grundseth

References

  1. Brandt, S., Statistical and Computational Methods in Data Analysis. 2nd edition, North-Holland Publishing Company, Amsterdam, 1978.
  2. Press, W.H. et al., Numerical Recipes in C. Cambridge University Press, Cambridge, 1992.
  3. Valdes, F., Psfmeasure/Starfocus: PSF Measuring Algorithms. Third ADASS conference proceedings, October 1993, Victoria, Canada.
  4. Boutenko, V., Evaluation de la qualité des images astronomiques. Rapport du stage de 3ème Année, Imprimerie de TELECOM Paris, Paris, 1994.

Figures captions

Figure 4a: Example of a FWHM ellipse whose measures using the IQE tool yield significant errors. Figure 4b: Instability of the FWHM found by interpolation methods. The PSF in two cases are almost equal, while the measured FWHM differ by a factor 2.5.

Figure 5a: Spiral scanning of images in background determination. Figure 5b: Typical ``unrolled'' image of a star.

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News From the PEGASUS Corner

David Hooper, a University of Victoria cooperative student, spent this past summer at CFHT working on adding an on-line help system to PEGASUS. David was also CFHT's first coop student to be acquired from the computer Science Department.

The help system, whose functional specifications were done last year by Mary Jo Link, provides PEGASUS users with on-line help text at three levels.

PSM Menubar Help
pull down menu help with an overview of PEGASUS (Help menu selections),context-sensitive help for each of the menubar pushbuttons,
Xform Help-Pushbutton Help
the "Help" button on an Xform brings up help text for the form. This help includes general help on the Xform followed by specific help for each of the PEGASUS metawidgets on that form (radio button, check boxes, text fields, etc).
Xform Context-Sensitive Help
pressing the F1 function key with the mouse pointer over a metawidget brings up help specific to that metawidget.

Help text resides in PEGASUS par files. For a typical PEGASUS application, this is the same parfile that defines your form. For other applications, such as SAOimage, there is a parfile generated specifically to contain help text.

GXE (PEGASUS' Graphical Xform Editor) has also been enhanced by Linda Evans to provide an easy-to-use help editor for forms. This will eliminate the need to edit par files in order to add the help text.

The system is currently awaiting the input of help-text. This will mainly come from existing manuals and support staff at CFHT.

Future enhancements include hypertext and an Xmosaic interface to allow on-line viewing of CFHT User's Manuals.

J. Kerr

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Detector Progress Report

The situation of detectors at CFHT is looking up.

First, the detector group is now complete with the arrivals of Phil Cizdziel and Steve Milner. They are coming up to speed with learning the GENIII system (software & hardware), operations, procedures, setup etc.

Concerning CCDs, the battlehorse detector is still Loral3, a blue coated 2Kx2K, 15 micron pixel chip. Lick2 has the same physical characteristics as LORAL3 but is un-coated and has not been integrated in the GENIII system world, (so the read-out time is somewhat longer that Loral3's 320 sec).

Efforts of CFHT to acquire a large, thinned CCD have been unsuccessful so far. Of the 2 wafers (4 CCDs per wafer, provided by G. Luppino) that were given to M. Lesser (Steward Observatory) for thinning, only two CCDs were successfully processed; and of these 2, the first one was damaged in the shipping to CFHT and the second one was damaged during integration in the dewar. This latter CCD has been returned to Loral to investigate possible ways of reviving it.

Note however, that the same collaborative effort is still underway between G. Luppino and CFHT, and M. Lesser has been provided with 2 more wafers. CFHT is also awaiting a 2Kx2K, 13 micron pixel thinned CCD ordered from EG&G Reticon last year. Delivery was expected in December of 1993. Finally, the so-called TEK3 chip has been received, and is awaiting integration in a dewar. This thinned, 1Kx1K chip constitutes a compromise between sensitivity and resolution, since the large pixels (24 micron) somewhat undersample prime focus average seeing. However, TEK3 is still a good choice for high sensitivity spectroscopy on MOS or SIS.

CFHT is currently negotiating with G. Luppino of the UH for the fabrication and assembly of a set of 3 dewars. This will solve our problem of short (LN2) hold times when used with MOS/SIS, since Luppino dewars are known to have 24 hour (or more) hold time. The contract also includes the integration of CCDs into the dewars. Which ones will be integrated first depends on the results of M. Lesser and the delivery of the Reticon CCD. TEK3 is likely to be one of the first chips to be put in one of G. Luppino dewars (since we have it in hand) followed by whichever thinned 2K chip CFHT receives first (Lesser or Reticon).

On the software side J. Wright, helped by D. Mckenna on the hardware side, have been through an extensive work of familiarization of the GENIII system since the departure of C. Clark and S. Smith. The first release was plagued by a few very bothering bugs: "zero pixels" introduced in the frames (two varieties of this particular problem), intermittent increased level of read-out noise, and unreliable functioning of the HOLD-ABORT- STOP exposure buttons. The causes of these problems have been identified, and solutions (plus improvements including shorter readtimes) will be implemented in a new release of the GENIII system that should take place this summer. Diagnosis of these failure modes has been frustrating (and difficult) because there is only one complete GENIII system at CFHT... the one used at the telescope almost every nights! The detector group is looking into this issue and the issue of a larger and better equipped Waimea Detector Laboratory.

Visiting observers may recall problems experienced with one of the RedEye Cameras at the end of 1993. (One quadrant would fail intermittently). This was traced back to the NICMOS chip which was returned to Rockwell for further tests. The cause of the failure could not be identified, but Rockwell nonetheless kindly replaced the chip. The chip has been reinstalled into the RedEye gold dewar and is currently awaiting final testing in Waimea.

R. Arsenault, P. Cizdziel, J. Glaspey, B.Cruise

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Telescope dimensional change due to zenith angle and temperature effects.

The two main dimensional effects on any steel structure are temperature and gravity. The main structure of the Canada-France-Hawaii Telescope is steel. On any given night of operation the telescope may see temperature ranges from -5 C to +10 C. The telescope is capable of motions from an upright position to nearly horizontal thereby changing the effect gravity has on its mass.

This past year Ed Stokes, John Seerveld, and Derrick Salmon conducted an experiment to determine telescope flexures in the optical axis dimension for the f/35 telescope configuration. The distance between the bottom of the Cassegrain Bonnette and the f/35 mirror front surface is approximately 13500 mm. Using a Hewlett/Packard Laser Interferometer we attempted to measure the relative motion between the Cassegrain Bonnette and the f/35 mirror. The interferometer was mounted at the Cassegrain Bonnette and corner cube mirrors were mounted at various locations on the f/35 upper-end. The bulk of the telescope motion was zenith - 5 hour angle east - zenith - 5 hour angle west - zenith. We also attempted to move north - south, but the interferometer would lose lock. The results from two days of data collecting show that the current f/35 to Cassegrain Bonnette distance grows in length approximately 0.5mm (0.020 in) as the telescope slews 5 hour angle in declination with no noticeable hysterysis.

Two studies have been done to determine the dimensional change in the optical axis due to temperature changes. The first was done in France by INAG and the second by René Racine. R. Racine says that for every degree C the telescope will change 0.060 inches (1.5mm) in the axial direction. This number seems to confirm the work done by INAG. Rough calculations using a bar of steel 13500mm in length predict roughly 0.15mm/ C (0.006in/ C).

E. Stokes

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Summit Operations

A change in the organization of the Operations group to introduce a new position at CHFT, the Summit Operations Manager could not have been developed at a more timely point in our Telescope's life. More than a supervisor of the Daycrew, this position was filled by Rod Hendrix to utilize his knowledge and expertise to assess the aging hardware at the Summit. Rod and I face the challenge of evaluating each Telescope and Dome hardware system knowing that our decisions are imperative to maintaining the excellent reputation for operational reliability that CFHT is renown for.

Rod's first project was to attack and correct the Air Conditioning and Ventilation system for the Control room and other work spaces in the building. This not only makes the working environment more bearable, but affects the Dome temperature by flushing air downward floor by floor away from the refrigerated Dome space.

A second project currently underway by Rod and myself is assessment of the Dome Shutter drive system for updating or refurbishment. Last year the jamming of one Motor's brake resulted in a closed Dome until the motors could be de-coupled from the shutter one at a time to isolate the failed unit. Our goals for the renovation is to make the system more accessible for troubleshooting, and more reliable by servicing or replacing components at a selected maintenance interval. The first step has been to design a handling unit to allow removal of the Motor assembly without straps and rigging. In conjunction we are re-designing the mounting flange between the Motor assembly and the Shutter to make it effortless to move a Motor in and out of mesh. The final decision on selection of a new motor and control, or renovation of the existing motor and controls is contingent upon information the manufacturers are researching for us.

Replacement of the inflatable seal between the Dome Shutter and the Dome skin is planned for completion in July with an easier to install and maintain seal. The seal is most easily envisioned to be much like a long car wiper blade which slides lengthwise up and down the Dome while attached to the sides of the Shutter. The wiper is made of an Ozone and sunlight resistant polymer. The seal will be installed in sections directly on the Shutter from outside the Dome top while moving the Shutter progressively down. This makes installation less hazardous and allows for routine maintenance.

R. Atapattu

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Primary Mirror Cooling Project - An update

The mirror cooling project was initiated in 1992 at CFHT to solve the problem of having the mirror averaging 1.5 degrees C warmer than the night ambient air despite our cooled dome floor. Due to other pressing priorities, the cooling project was put on hold until it's recent revival.

The initial design included a enclosed mirror cell, cooling unit, dryer and fan which were mounted rigidly on the telescope. With the revival of the project the design has changed to group the components together and position them on the Dome floor away from the Telescope, and duct up the cool air into the enclosed mirror cell. This eliminates three problems that were not resolved in the initial project design:

R. Atapattu

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Use of the Mosaic Information Browser at CFHT

CFHT has been using a World-Wide Web browser called Mosaic since September of 1993. Mosaic is an Internet-based multimedia information-retrieval application which is available from the National Center for Supercomputing Applications at the University of Illinois. Mosaic allows one to discover, retrieve, and display documents and data from all over the Internet using a uniform interface. Documents can be graphic images, audio, video, as well as text. A significant capability of Mosaic documents is that they can contain hypertext links which point to other documents.

While Mosaic at CFHT has become a valuable tool solely for allowing easy access to information external to CFHT, it is becoming even more important as a server of CFHT information to the astronomical community. For example, information such as CFHT observing schedules, newsletters, archive information, and postscript versions of instrument manuals are now made available to the Internet via Mosaic. The CFHT library maintains an astronomy related meetings list which is widely accessed via Mosaic, and has recently started a Mosaic project which presents summaries of instrument manuals from any observatory willing to participate. Within this one page manual summary is a hypertext link to the actual manual, wherever it is located on the Internet. Another Mosaic project in the making is the creation of hypertext versions of CFHT instrument manuals. This would allow immediate interactive access to this information from anywhere on the Internet, and would reduce the need to retrieve and print large manuals.

While CFHT is currently serving valuable information via Mosaic, the project is still in a formative stage with much more to come. Watch for announcements of new offerings. The CFHT Mosaic home page or starting point, may be accessed by pointing to the following URL: "http://www.cfht.hawaii.edu/"@. Send questions or comments about Mosaic at CFHT via email to xmosaic-admin@cfht.hawaii.edu.

R. Link

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Scientific News


Turbulence in Outflows from Hot Stars

Sometimes it takes a while to properly digest good data. But it can be well worth the wait, especially if something interesting and new comes out at the end. And indeed, we believe it has in this case.

Back in 1987 and 1988, AFJM and CR amassed a substantial bank of high quality, repeated spectra at the Coudé focus of the CFHT for all 8 bright Wolf-Rayet stars in Cygnus. They complemented these by 4 southern WR stars in 1989, using the échelle spectrograph "CASPEC" at the CFHT's twin 3.6m telescope at ESO, La Silla. In all, some 20-30 spectra (S/N = 300 or more, R = 30,000) are uniformly available over 3-4 nights for each of these 12 WR stars (mainly HeII 5411 in WN5-8 and CIII 5696 in WC5-9 stars).

The initial goal was to systematically investigate the nature of the variable substructures seen previously on some WR emission lines (e.g Moffat et al. 1988). It was already intuitively clear that one was likely dealing with a global phenomenon of variability in WR winds, whose broad emission lines arise due to projected Doppler motion of hot plasma in all directions away from a central hot core.

The above data served as the basis for CR's Ph.D. thesis (Robert 1992; see also Moffat & Robert 1992). In that study, multigaussian analysis was used to extract information regarding the emission substructures. This appeared to work fine and led to some very interesting results:

These results suggest (see Moffat & Robert 1992), but do not prove, that one is seeing anisotropic, supersonic turbulence of a compressible medium (the expanding wind), much as is seen in giant molecular clouds (GMC; see Gill & Henriksen 1990). As such, the observed spectral subpeaks would represent individual eddies, possibly caused by some kind of wind instability leading to shock dissipation, and propagating outward in the wind. In fact, one could plausibly extrapolate the observations to lower fluxes, so that the whole wind would be in a state of full-scale turbulence. In this case, we would be observing only the tip of an iceberg!

This investigation received a considerable boost last year when two of the authors (AFJM & RNH) met at the Annual Québec Astronomy Meeting in the Laurentians just north of Montréal, after an invigorating cross-country ski break. When AFJM showed RNH some of the fine data revealing numerous structures on emission lines, it occurred to the latter that, by analogy with some of his recent work on GMC's (and now on large scale structures in the Universe), the WR spectral data were rife for analysis using a relatively new technique called wavelet analysis.

The idea of wavelets (see e.g. Farge 1992) is not too difficult to appreciate. One looks for a mathematical function which is not too different in shape compared to the subpeaks one is trying to analyze. A good simple function for this, often used in other contexts, is a so-called Mexican Hat; it is nothing more than the second derivative of a gaussian. Then one convolves the Mexican hat with the original data - see Fig. 6 - (in our case, with one spectral line in one star at a time, normally after subtracting off the temporal mean profile), for a complete series of normalized wavelet widths (see Lepine 1994). Fig. 7 shows how this process acts like a kind of filter, enhancing subpeaks of width most similar to the wavelet widths Âv, while subduing others, especially of widths more and more different from Âv. From this series of convolutions, one can then extract individual fluxes (f), velocity widths Âv and central positions of each subpeak. When this is repeated for all 26 spectra of the sample star shown here (WR 135, WC8), we can make some statistical studies, as illustrated in Fig.8a. Note the advantage of wavelets over Fourier sine-waves: the latter appropriate only for periodic phenomena, and after convolution one looses positional information.

Fig. 8b shows that noise produces a relation as expected; i.e. if we write , where h is the height of the subpeak, the detection threshold will occur at a fixed h level. In Fig. 8a the real subpeaks yield the scaling law f proportional to , intrinsic to the region of the WR wind where CIII 5696 is formed. Analysis for other stars are currently underway, with similar results already emerging.

Another scaling law involves the lifetime as a function of flux. However, for the time being, this relation is rather compromised by the finite duration of the nightly observation rythm.

Why are scaling laws important? When energy dissipation occurs via turbulence, it normally implies some kind of cascading, with the usual conservation laws, from one scale of eddy (with characteristic size ) to another, whether it be from large to small (as is most frequent) or vice versa. In the well-known case of GMC's (e.g. Henriksen 1991) two constraints are believed to prevail:

These lead to and . The same result follows if one replaces (a) by constant opacity: .

It is tempting (for lack of any other justification for now) to assume that these relations also apply to hot-star (e.g. WR) winds. However, in that case, and l are not directly observable. Rather, we use for recombination emission at T ~ const, and thus we predict - exactly as observed in WR winds! Is this a mere coincidence? We believe not, but this point certainly needs independent verification, e.g. by looking for another scaling law. For example, we are planning to observe the lifetimes for different substructure widths in one star observed continuously over several days from several observatories at different longitudes.

In any case, the interpretation of the varying subpeaks as due to turbulence is fully reinforced by consideration of other aspects, such as the mass spectrum. Again, we do not observe the turbulent cell mass directly, but can obtain it from , along with the above scaling laws: . These give . Thus, using the observed flux histogram for WR 135 (Fig. 9): , we get , where . With close to -2.0 +- 0.2 for two stars investigated so far, we find ( ) = -1.5 +- 0.1. How close this is to the average mass power law from cloudlets in GMC: = -1.5 (Williams & Blitz 1993), or from HI clouds in quasar Lyman-alpha forests: = -1.5 (Giallongo et al. 1993)!

Another aspect concerns anisotropy. Fig. 10 shows the normalized velocity width of the subpeaks for different positions on the CIII 5696 line of WR 135. Since this line is formed in the nearly constant terminal speed portion of the wind, structures that appear at the blue (red) edge must be moving towards (away from) the observer, while those forming near line center must be propagating away from the star in the plane of the Sky. Thus, Fig. 10 tells us that the turbulent cells that produce the observed emission subpeaks are elongated more in the radial direction than the tangential direction, relative to the central core. Again, this is like cloudlets in GMC (Fleck 1992), although the orientation of the major axes there is random, governed by fluctuating gravitational fields, whereas in the hot winds it is the radially directed radiation pressure which dominates to make the major axes all point more or less readily to the central star.

While more work remains, the evidence is already quite encouraging that WR (and thus possibly all hot-star) winds are highly turbulent. This has several far-reaching implications, which for lack of space, can only be briefly mentioned here:

We hope to follow these up in the near future. An the frequent buzz-word between AFJM and RNH these days is: "We must go skiing again..."

A. Moffat and S. Lépine, Université de Montréal and Observatoire du Mont Mégantic
C. Robert, Space Telescope Science Institute
R.N. Henriksen,Queen's University

References

Figures Captions

Fig. 6: Montage of one night's data from CFHT for the flat-top emission profile of CIII 5696 in the WC8 star WR 136 = HD 192103. The spectra are separated by one hour on average, with the mean calculated from all 26 spectra available for this star on 4 consecutive nights.

Fig. 7: Normalized wavelet transforms of a sample difference spectrum (the bottom one from Fig. 6). A sample Mexican Hat function is also shown at an arbitrary position.

Fig. 8a: Distribution f vs. Âv of all detected substructures on all 26 spectra of CIII 5696 in WR 135, using wavelets. Large symbols are real features seen on at least 2 successive spectra at early the same position on CIII 5696. Small symbols refer to noise peaks, as in (8b). Fig. 8b: Noise substructure distribution for WR 135 as in (a) but for the continuum near CIII 5696. The straight line of slope 0.9 plus or minus 0.2 is a best fit.

Fig. 9: Flux frequency spectrum of real substructures in CIII 5696 of WR 135, showing a power law index of -1.9 plus or minus 0.2. The open symbol refers to incomplete data at the faint end and was neglected.

Fig. 10: Normalized substructure width versus position on the CIII 5696 line for real features intrinsic to WR 135.

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Distribution de l'émission à 3.3 dans l'enveloppe circumstellaire de BD30+3639

La plupart des Nébuleuses ou Proto-Nébuleuses Planétaires (PN et PPN) riches en carbone (C/O>1) émettent fortement dans les bandes IR à 3.3, 6.2, 7.7, 8.6 et 11.3 . De façon générale, ces bandes observées en direction de nombreux objets astrophysiques sont probablement émises par de grosses molécules Polycycliques Aromatiques Hydrocarbonées (PAH) dont la température vibrationnelle fluctue après l'absorption d'un photon UV (Léger et Puget 1984). Les observations du plan galactique dans la raie à 3.3, obtenues à l'aide de l'expérience ballon AROME (Giard et al, 1988), ont montré que ces molécules sont présentes dans la plupart des régions où le champs de rayonnement est suffisant pour les exciter. Globalement, les PAH semblent donc une composante omniprésente du MIS occupant, après H2 et CO, le troisième rang des abondances moléculaires. Dans le cadre du modèle PAH (voir Désert et al. 1990), une fraction importante de l'émission détectée dans la bande à 12 du satellite IRAS provient de l'émission des PAH (bande à 11.3 et pseudo-continuum). L'analyse des données IRAS montre qu'il existe de fortes variations spatiales du rapport 12/1000. En particulier, l'émission à 12 décroît systématiquement (comparativement à celle à 100) en direction des régions HII. Une décroissance similaire de l'émission dans la raie à 3.3 en direction de régions HII a été mise en évidence pour certaines interfaces entre nuages moléculaires et régions HII dans la Galaxie (par exemple M17): Giard et al. 1992). L'émission à 3.3 des galaxies extérieures montre un comportement similaire. Ceci peut être interprété par la destruction des PAHs dans les régions de fort rayonnement UV, mais plusieurs types d'altérations physiques pouvant donner lieu aux variations observées ont également été proposées.

L'origine des PAH observés dans notre Galaxie reste incertaine. Les modèles de chimie interstellaire indiquent la possibilité de former les PAH dans le milieu dense au voisinage des géantes rouges riches en carbone (voir Frenklach et Feigelson 1989, Gail et Selmayr 1987). Néanmoins, le champs de rayonnement y est insuffisant pour que les raies IR y soient observables. Lors de l'évolution vers le stade de Nébuleuse Planétaire, la température de l'étoile centrale augmente rapidement et le flux UV devient suffisant pour exciter les particules et former une région HII autour de l'étoile. Les enveloppes circumstellaires autour des nébuleuses planétaires sont donc des régions où les PAH se sont formés récemment mais où leur destruction par le rayonnement est probablement déjà à l'oeuvre. Nous présentons ici les images dans la bande des PAH A 3.3 de la nébuleuse BD30+3639. Ces images sont interprétées afin de contraindre les processus physiques que subissent les PAH à l'intérieur des régions HII denses.

Les images présentées figure 11 ont été obtenues en Avril 1991 à l'aide de la caméra IR CIRCUS 128 x 128 montée au foyer f/36 du CFHT. Les images sont obtenues dans 2 filtres (CONT et PAH) centrés à 3.3 et une résolution spatiale de 0.25"/pix. Le filtre CONT couvre une large bande de longueur d'onde ( = 0.9) et intègre l'émission dans la raie à 3.3 ainsi que le continuum voisin. Le filtre PAH, plus étroit ( = 0.17) sélectionne essentiellement la bande d'émission IR. La distribution de l'émission dans le continuum et dans la raie IR sont déduites par soustraction, en combinant les images dans ces deux filtres avec celles de sources d'étalonnage n'émettant pas dans la raie des PAH. Les images montrent que l'émission provient essentiellement d'un anneau entourant l'étoile centrale et correspondant à la région HII détectée en radio (Masson 1989). Le long de cet anneau, plusieurs condensations sont visibles. Deux d'entre elles, au nord-ouest et au sud de l'étoile centrale correspondent à deux maxima de l'émission radio continuum. La troisième, à l'est, est caractérisée par un rapport entre l'émission dans la bande et dans le continuum significativement plus fort que pour les deux précédentes. L'image continuum montre l'existence d'une barre horizontale qui intercepte la région HII à l'endroit des deux premières condensations. Dans le continuum comme dans la bande à 3.3 , 65-70% de l'émission provient de lignes de visées en direction de la région HII (r<2.6"). Un résultat similaire a été mis en évidence par Woodward et al. 1989 pour NGC 7027.

Néanmoins, la fraction des PAH se trouvant effectivement à l'intérieur de la région ionisée est inférieure à cette valeur, car le champs de rayonnement et l'émissivité dans la raie décroissent rapidement avec la distance à l'étoile. Les PAHs contribuant à une fraction significative de l'extinction dans l'UV, la détermination de profil d'abondance dans l'enveloppe requiert l'utilisation d'un modèle de transfert du rayonnement UV incluant les effets des variations d'abondance. Le profil radial de l'abondance des PAH dans l'enveloppe de BD30+3639 déduite à l'aide d'un tel modèle contraint par les images IR est représenté figure 12. L'abondance croît de façon monotone du rayon intérieur (r=1.8") jusqu'à l'extérieur de la région ionisée où elle atteint environ 1.2 fois celle proposée pour le MIS local (DBP). La fraction des particules effectivement situées à l'intérieur de la région HII, 12% est significative. Une abondance des PAH similaire à celle du voisinage solaire dans une région HII où le champs de rayonnement >10E6 est plus fort que dans la majorité des régions HII galactiques peut sembler surprenant. En fait, ceci peut s'expliquer par la forte densité des régions HII associées aux nébuleuses planétaires. Les processus de reconstruction proportionnels à la densité y sont en effet généralement plus efficaces que dans les régions HII galactiques moins denses. Ceci tend à équilibrer plus efficacement la destruction ou l'altération des PAH par l'intense champs de rayonnement UV.

Plusieurs processus ont été proposés pour expliquer la diminution de l'émission à 3.3m dans les régions fortement irradiées:

L'analyse des images obtenues à l'aide de la caméra CIRCUS permet de contraindre le type de processus responsable des variations observées. Le calcul du degré d'ionisation montre que les PAH sont en majorité ionisés dans la région HII autour de M17 mais pas dans celle de BD30+3639 où les recombinaisons avec les électrons libres sont plus fréquentes. La comparaison quantitative du profil d'abondance dans BD30+3639 avec les prédictions des modèles de destruction et de déhydrogénation indiquent que les observations sont compatibles avec la destruction par explosion Coulombienne de gros PAH ( 80 atomes de carbone) et la déhydrogénation par Photo- Thermo Dissociation de molécules relativement petites ( 20 atomes de carbone). Une réponse plus complète à l'origine des variations observées passe indiscutablement par l'observation d'un plus grand nombre de Nébuleuses Planétaires et régions HII galactiques dans la bande à 3.3 ainsi que dans celle à 11.3 qui permettront de déterminer la taille des PAH de façon indépendante de leur couverture en hydrogène. Finalement, l'abondance des PAH déduite ici semble faible pour que des objets tels BD30+3639 enrichissent substantiellement le MIS en PAH à l'échelle galactique. Les fortes abondances déduites au voisinage de certains nuages moléculaires (Bernard et al. 1993) pourraient indiquer que leur formation a également lieu dans le MIS beaucoup plus froid et diffus que le voisinage des étoiles carbonées.

J.P. Bernard, Infrared Processing and Analysis Center,California Institute of Technology M. Giard, Centre d'Etude Spatiale du Rayonnement P. Normand et D. Tiphène,Département Spatial, Observatoire de Meudon

Références

Figure Caption

Figure 11: Images de BD30+3639 dans le continuum à 3.3Êm (a) et dans la bande à 3.3 (b). Les deux images sont en Wcm-2 sr-1 intégrés dans le filtre PAH (0.17). Le contour le plus bas correspond à 10-9 Wcm-2 sr-1 et 4 x 10-9 Wcm-2 sr-1 respectivement. Deux contours successifs sont séparés par un facteur 2.

Figure 12: Abondance des PAH normalisée à celle du voisinage solaire déduite de l'image dans la raie à 3.3, en fonction de la distance à l'étoile. La courbe en pontillés (échelle de droite) représente l'énergie moyenne absorbée par un PAH, normalisés au voisinage solaire. La barre horizontale indique la taille de la région ionisée.

Figure 13: Abondance des PAHs en fonction de la fraction des PAH sous forme de dictions dans BD30+3639 et pour deux positions dans la région HII M17SW.

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La configuration ARGUS pour spectrographie bidimensionnelle avec MOS

Après l'expérience acquise avec SILFID en matière de spectrographie intégrale de champ par fibres optiques, un nouveau mode d'observation a été proposé par Paul Félenbok (DAEC, observatoire de Meudon) pour le complexe MOS/SIS. Il utilise un faisceau de 655 fibres de silice (diamètre individuel 110 , longueur 80 cm), arrangées pour remplir une surface hexagonale à l'entrée et alignées suivant une pseudo-"fente" en sortie.

Ce système se monte après le miroir de renvoi de MOS et le court-circuite. Pour les observations, le miroir doit être escamoté la "fente" est située dans un tiroir en tous points identique à un tiroir porte-masque habituel de MOS. Jean-Pierre Lemonnier (DAEC observatoire de Meudon) a fait l'étude mécanique et optique de ce dispositif; la réalisation du faisceau de fibres a été confié à la société SOVIS (France). On peut en trouver un schéma par ailleurs (proceedings IAU colloquium 149 "Tridimensional Optical spectroscopic methods in Astrophysics", sous presse).

Ce système baptisé MOS/ARGUS a donné de bons résultats lors d'une mission inaugurale en Juin 93 (cf. figure 14), à l'issue de laquelle on a fait quelques modifications mécaniques mineures. Le montage peut maintenant s'effectuer en moins de 15 mn. Malheureusement, le mauvais temps a empêché toute observation pour la seconde mission de Février 94.

Les caractéristiques de MOS/ARGUS sont résumés dans le tableau 1. La "fente" étant horizontale, la dispersion doit se faire suivant une direction perpendiculaire à la direction habituelle dans MOS. On a donc réservé une roue à grisms pour ce mode.

Table 1: Caractéristiques du mode ARGUS de MOS:

Echantillonnage Spatial  	0.4"
champ couvert (CCD 2048x2048)	8" x 12"
intervalle spectral		3800 - 9000 Angstroms
résolution(O300)		7.5 Angstroms
grisms disponibles		R150, O300, R300,600, R600, U900

Le tiroir ARGUS comporte, en plus des fibres, une position pour l'observation en imagerie directe et une position pour spectrographie avec un masque MOS classique. Pour ces 2 modes d'observation, il faut bien sûr que le miroir de renvoi de MOS soit remis en place et les fentes du masque doivent être percées perpendiculairement à l'orientation habituelle. On peut alors utiliser les 3 modes d'observation (imagerie, spectro multi-objet, spectro bidimensionnelle) au cours d'une même nuit sans aucun démontage.

Le Conseil Scientifique du CFH a récemment suggéré que MOS/ARGUS ait le statut de "guest instrument". Après acceptation, il pourrait donc être proposé en usage général, probablement pour le second semestre 1995.

C. Vanderriest

Figure Caption

Figure 14: Image monochromatique [OIII] du quasar 4C 37.43, reconstitué à partir des spectres obtenus par MOS/ARGUS (observateur: C. Crawford)

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Directors' Corner


Publications Based on Data Acquired at CFHT

While preparing the annual report draft, we discovered that the CFHT library is not receiving copies of a significant fraction of the scientific papers accepted for publication that were based on data acquired at CFHT. The librarian informed us that this has been the case for some time. Considering that this information is the best way to demonstrate how CFHT facilities benefit the community and, hence, to justify the CFHT budget requests, it is important that a complete list of articles involving CFHT be known.

The elements which obviously demonstrate that CFHT is not receiving notification of such articles for inclusion in the annual report are the following:

    The list of articles you have regularly seen in the annual report is collected by the librarian:

  1. We have made copies of those articles which were quoted in the requests for allocation of time of semester 94II. By this procedure we have augmented the existing list of 1993 accepted publications by 18%.

  2. Since we know that many authors are not requesting time each semester, we suspect that we are missing more than 25% of articles made in 1993 based on CFHT data.
Therefore the following actions are being taken:
  1. In the observing time request form we will add in the section for "publications resulting from CFHT observations" the following text: Check that a copy of all publications have been sent to CFHT library.

  2. In the letter notifying PIs of the time granted to them, we will remind them of their obligation to refer to CFHT (see section 2.14.1 of CFHT Observers' manual). All publications based on research results obtained with the CFH Telescope shall carry the following credit line: Asterisk by the author's name to refer to a footnote stating: *Visiting Astronomer, Canada-France-Hawaii Telescope operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France and the University of Hawaii.

    We will remind them also to give a scientific report on their program for the annual report.

  3. The Director of CFHT will send a letter to the first author of any paper based on data obtained at CFHT, but not mailed to CFHT, asking for a copy and pointing out the fact that by not doing so the author is not helpful in maintaining a good level of support for the instrument he/she has used.

  4. We will make the list of published papers based on CFHT data accessible on our World Wide Web server and it will be updated frequently.
We hope that these actions will be sufficient and we are opened to any other suggestions which could help to effectively improve the present situation.

P. Couturier, J. Glaspey

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Technical Details in Observing Proposals

The first priority we all have in writing observing proposals is to explain and justify the project scientifically, but the Resident Astronomers at CFHT wish to emphasize the need for proposers to furnish the appropriate technical details as well. CFHT carries out a technical appraisal of every proposal submitted in order to inform the TAC of those programs for which the number of nights requested seems either too large or too small, or of those for which there are significant problems with the ability to accomplish the scientific goals due to misunderstandings, for example, of how the particular instrument being requested functions (e.g. requesting a coudé train change in the middle of the night - impossible), or a poor choice of the instrument configuration (e.g. specifying the wrong grism for MOS or SIS, say). It is important to describe [briefly] how the observations will be made and what calibration data will be required. If inadequate information is supplied to carry out the technical appraisal, we inform CTAC, CFGT or the UH TAC accordingly, and the proposal may be rejected outright without further consideration. Some PIs also seem to feel that the CFHT staff will remember the details of what they used the "last time" they came to CFHT, which is a very poor assumption.

Furthermore, once the proposals are recommended for scheduling, CFHT must have sufficient information to prepare the observing schedule in the most efficient manner for each program. We really do need coordinates of the object fields to be observed (with the primary science target clearly indicated!) to enable us to schedule the run at the best time of year possible. (Of course, the wise Principal Investigator will provide alternate targets in case the program is not so highly ranked by TAC to guarantee optimal scheduling.) Most PIs realize that just because they request a particular month, they may not get scheduled at that time, due to pressures from higher ranked proposals.

In summary, it is in everyone's best interests for proposals to contain all of the information that is asked for on the form.

J. Glaspey

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Québec Workshop of May 17-18 1994

In 1993 the CFHT Scientific Advisory Council recommended the organization of a workshop, aimed at defining the science programs that could be carried out at CFHT with PUEO, the CFHT adaptive optics Bonnette. This workshop took place this spring, and approximately 45 astronomers gathered in Québec City to present their ideas about the scientific potential of PUEO.

The workshop first started with a brief reminder, by the authors of PUEO's opto-mechanical design and expected performance. A progress report of the fabrication was given. Other talks focussed on the AO system of the IfA (M. Northcott) who obtained diffraction limited images of some young stellar objects (ZCMa, T Tau), evolved stars and proto-planetary nebulae (Red Rectangle, Frosty Leo etc.), planet satellites and galaxy cores (M31, NGC 4151). Then observations with the COME-ON+ system were presented by (J.-L. Beuzit). He also gave a useful description of the typical observing procedures with an adaptive optics system. Then R. Bacon presented the OASIS integral field spectrograph, which is being built for use with PUEO.

J.-L. Beuzit and D. Alloin presented the astronomical results obtained mainly with COME-ON+. In the field of planetary studies, determination of the axis of rotation of Céres, and maps of the surface of Titan were obtained. Spatial resolution in multi-components of compact stellar cluster like Sanduleak -66 41 or R136 in 30 Doradus were obtained as well. Close double stars orbit determination allowed direct measurements of the mass of very low mass stars. This system was shown to be very suitable to the observation of circumstellar environment (dust envelopes, reflecting nebulae). Some active galactic nuclei and Seyfert were also observed (NGC 1068, NGC 7469). The experimental limiting magnitude, for a significant image improvement, was reported to be mv=13. These talks gave a good overview of the instrumental possibilities and limitations of AO observations.

F. Ménard presented an enthusiastic talk on the potential of adaptive optics for the study of young stellar objects. He showed that this can be a high-potential niche for PUEO at CFHT, as these objects have dimensions of the order of 1-2 arcsec, are conspicuous in the IR and often bright in the visible, therefore can be used as their own reference source for wavefront sensing. Spatially resolved polarization studies of the nebula around the accretion disks can provide interesting hints on the nature of the sources.

Solar system studies with adaptive optics can also greatly benefit from adaptive optics as was shown by P. Drossart. Indeed, the range of magnitude of the potential targets fits well within what is attainable with PUEO. Observations obtained with COME-ON+ of the poles of Jupiter were shown to support this idea. He stressed that for planetary studies an important, if not essential, system capability would be the non-sidereal guiding speed; for instance observation of a planet using its satellites as a reference source.

R. Racine presented a talk of the potential of PUEO for the studies of Globular Clusters. He underlined that PUEO will not allow a large gain in S/N ratio for photometric measurements. The most important gain will be in the separation of objects, making easier the identification of individual stars in these crowded fields.

M. Shara presented spectacular images of the refurbished Hubble Space Telescope. It illustrated the fact that imagery and spectroscopic follow-up by ground based observatories equipped with AO system of images obtained with HST will be important. Furthermore, it stressed the fact that adaptive optics is still the only way to obtain images in the infrared with a resolution comparable to the HST in the visible. Since there is no integral-field spectrograph in the HST future instrument plan, this will remain a unique capability of ground-based observatories.

P. Stetson reported on developments to carry out photometry on variable PSF images. A well elaborated mathematical approach that implies a good calibration of the PSF (many stellar images in the field) provides a model of the PSF for any location in the field. Vital concerns in the elaboration of this procedure were to minimize computer processing time and memory use.

Extragalactic astronomy was described by R. Bacon, M. DeRobertis and S. Lilly. Whereas normal and active galactic nuclei can benefit from AO to probe the very inner parts of the core and provide crucial information on high energetic phenomena and galaxy dynamics, statistical cosmological studies seem not to be suited to AO. The latter is mainly due to the photon starved regime of cosmological objects and the need for large fields of view for statistical studies.

From an instrumental point of view, it was stressed by many participants that the near infrared coverage of the spectrum, in imagery as well as in spectroscopy will not be covered by the first generation of instruments. Furthermore, it became obvious during the discussion that a coronograph and a polarimeter would be extremely useful for the study of young stellar objects. Although there are no plans at this stage for such instrumentation, it appears technically feasible to implement these modes in PUEO. A coronograph could be made by simply inserting a mask in the f/8 focal plane assembly. There is provision already to have 2 calibration light sources and a mask installed in the f/8 focal plane assembly. A semi-transparent chronographic mask would decrease the bright source intensity by a large factor, while leaving enough signal for the wavefront sensor to analyze the wavefront perturbation on this source. The polarimeter is somewhat more problematic since it cannot be installed in the instrument under PUEO. Given the numerous high angle of incidence reflections in the AO Bonnette, a large amount of instrumental polarization would be produced, preventing accurate astronomical measurements. A possible solution that will requires more investigation would be to insert a module at the level of the Cassegrain Bonnette.

Wished future developments in the field of adaptive optics at CFHT included artificial guide star capability and wavefront sensing on the 6 km atmospheric layer. Both solutions aim at solving the problem of reference sources, the first one by creating an artificial source while the second one would increase the isoplanatic patch size. Both are relatively complex solution to implement. Concerning the laser guide star, it seems reasonable to assume that the Mauna Kea will develop a common laser plan that could provide a laser beam to the various observatories. From an organizational point of view it also makes sense to have such activity coordinated by a centralized facility, given the numerous telescopes on Mauna Kea. The second solution implies a different optical design than the one of PUEO. PUEO senses the wavefront in the telescope aperture plane, and the solution proposed above would imply the development of another adaptive optics facility, which is not envisioned at this stage.

It was our impression that the participants, CFHT and SAC members left Quebec with a better idea of the possible science that can be carried out with PUEO and the instrumentation which will help to reach these goals. Proceedings of this workshop will be available by the fall of 1994.

As members of the scientific organizing committee, we wish to thank the speakers for their most interesting and stimulating presentations, and all participants for their interventions and interests.

R. Arsenault, F. Rigaut

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Staff Changes

Many new staff members have joined CFHT during the last semester. Welcome to all of them! However, the astronomer group deplores the departure of its two "senior" members.

Doug Simons has left CFHT at the end of March to take a position at the GEMINI office in Tucson. It is more than likely that his future duties will bring him back to Hawaii in the near future. Doug has been the infrared "guru" of CFH for the four years he spent with us. He is at the origin (after a twisted arm intervention of one of our past directors) of the 2 RedEye cameras. In four years, this project passed the stages of "eventual funding" to two fully blown, operational and competitive IR cameras. He has been the main coordinator of it although he is the first one to acknowledge the contributions of other CFH staff members. He has also initiated the low resolution spectral mode of RedEye which will be integrated in the future. Doug has certainly marked his passage at CFHT and he will be missed. Good luck to him and Judy!

Olivier LeFèvre also left CFHT at the end of March to return to the Observatoire de Paris-Meudon. He spent his last months at CFH as a visiting scientist, spending most of his time on research projects. Olivier has been striving at CFHT since February 1986, which is a remarkable performance for an astronomer! He has been pursuing an intense research activity in the field of high-redshift galaxies all along, while taking part in other CFH duties. He has been the editor of this bulletin from 1988 to 1990. During the last years he had the scientific technical responsibilities of the CCD imaging devices, and, not to forget, the MOS/SIS. Olivier has been following up the MOS/SIS since its early fabrication stages to the final commissioning and visitor use at the telescope. He has taken an active part to the preparation and on-site testing of the MOS/SIS acceptance tests. Without doubts he played an important role in the success of this instrument at CFHT. We wish him and Regine a smooth transition from the quiet and balmy Waikoloa life to the thrilling and stressful Parisian life.

Rohendra Atapattu has taken the direction of the operation and mechanical groups. Rohendra had been working for a year in the prototype and manufacturing department of a company specialized in the design of commercial display racks. Before that he was working for Rockwell International on the Space Shuttle product assurance. His main role was to review the various systems of the Space Shuttles after each flights, and taking decision on whether repair or maintenance or replacement of these systems were necessary. At CFHT, besides the supervision of the mechanical and operation groups, Rohendra follows up on the primary mirror cooling projects, and has designed a better seal for the dome shutter. Also, he has been investigating how to make the dome shutter more reliable, and how to recover from an eventual failure.

Rodney Hendrix arrived at CFHT at the beginning of March from San Francisco. Rodney had been working for 20 years in the San Francisco area on industrial construction plants. He acquired a vast experience in electrical system, plumbing, and other services provided on construction sites. He had been supervising several crews of workers and his experience will be put to contribution at CFHT as a Facility Manager. Rod spends most of his time at the summit supervising our daycrew and insuring a better communication/ coordination between Waimea and Summit activities. Since he arrived, he has supervised the cleaning of the visitor area, numerous small repairs, general energy management and general maintenance of the summit building. In the future he will be involved in the dome shutter seal change, the implementation of the primary mirror cooling system and the improvement of the controls for the upper ends interchange ring.

Philip Cizdziel arrived last May at CFHT from Loral Fairschild where he had been working for the last seven months on an infrared arrays. He acquired an extensive experience in the testing and characterization of IR arrays while at EGG Reticon from 1989 to 1993, and before that at the Santa Barbara Research Center on the analysis of IR arrays. He replaces C. Clark in the detector group and his duties will be to follow up on the acquisition of new dewars and new CCD chips for CFHT, and the development of a well equipped camera testing facility in Waimea. Furthermore, he has been asked to explore the best ways of improving our infrared cameras (larger arrays, new dewars (?)). He is also responsible for the very time-consuming and important task of responding to summit emergencies and setting up the standby team to summit detector problems and failures.

Steven Milner was on the research staff of Lincoln Laboratory from 1975 to 1990, where he was an engineer developing electro- optical space surveillance systems. Since 1990 he has been a member of the MIT Haystack Observatory and his principle focus had been on electrical and mechanical upgrade of the 37 m antenna and the design and construction of the 12 m Haystack Auxiliary Radar. Therefore, Steven has a "hands-on" experience in the building of complex electronic systems and in particular of cameras, including mosaics. He joined the Detector group at CFHT at the beginning of June and has been assigned the responsibilities of the GENIII controller, the FTS diodes project, MOCAM and will be responsible of implementing a small camera laboratory facility at the summit.

Mark Weber arrived at CFHT at the beginning of 1994 from the Institute for Astronomy in Honolulu where he had been working since 1989. There, he was the software engineer designer of the IRTF's adaptive optics system which involved the software system definition, hardware specifications and user interface design. Before that the IfA solar group used his services for a similar work on the imaging vector spectrograph of the MEES Observatory. Mark was working in Carlsbad (CA) previously to his hiring at IfA for CD Interactive Development for computers and before that for the Defense Advanced Research Agency on simulators. At CFHT Mark will use this vast experience on the development of the Adaptive Optics Bonnette user interface, and Coudé F/8 and F/4 improvement of their user interfaces using Data Views. Besides, he is responsible for the maintenance of Coudé F/4 including modifications and improvements to the control software. He will also manage the general documentation of CFH systems and its implementation of XMosaic.

Marc Azzopardi joined CFHT for one year as a visiting scientist last February. Marc comes from the Observatoire de Marseille and is helping out at various tasks at CFHT namely the support of MOS/SIS observing runs. He is actively pursuing his research in the field of stellar population of nearby galaxies. This research consists in the spectroscopic confirmation (using MOS) of photographically identified Wolf-Rayet stars and Planetary Nebulae in M31. He is also using MOS in a slitless spectroscopic mode to test for the completion of their photographic survey. We wish him a pleasant stay with us.

Jean-Pierre Véran is finishing his 16 months term as a military cooperant from France. Jean-Pierre had been at CFHT before as a stagiaire from the Ecole Supérieure Nationale des Telécommunications de Paris. During his stay, he has been involved in improving the archival of CFHT observations and various software group projects in particular the implementation of writing files on EXABYTE or DAT tape in the PEGASUS user's interface. We will have the chance to see Jean-Pierre again at CFHT since he is undertaking a Ph.D. under the supervision of F. Rigaut on the processing of images obtained with Adaptive Optics.

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CFHT Library Service


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Observing Statistics For The Next Semester (1994II)


The second semester of 1994 (94II) covers a total of 183 nights. During 94II, the telescope is scheduled for scientific use on 168 nights (92%) and for engineering 15 nights (8%). This compares with 167.5 scientific nights (93%) and 13.5 nights (7%) in 94I. During the 158 scientific nights for visitors, 62 observing programs are scheduled. The table below shows the distribution of these programs and the allotted nights between various instruments and configurations. It also shows the number of times each instrument will be installed (or reconfigured) on the telescope. Within the 6 month interval there will be 6 upper end exchanges.

                                                                      
CFHT INSTRUMENTS              Programs       Nights

FOCAM                             5            15
CF8                               2             7
GECKO                             3             8
MOS                              14            32
SIS                               7            17
RedeyeN                           2             6
RedeyeW                           3             9
FTS                               3             5
                                 ------------------
CFHT INST. TOTAL                 39            99


VISITOR INSTRUMENT            Programs       Nights

BEAR                              3             6
C10micron                         3             5
CIRCUS                            3             7
GSU                               1             4
IfAAO                             1             3 
LAPOUNE                           1             5
MOCAM                             2             6
MONICA                            1             4
MOS-ARGUS                         1             3
QUIRC                             2             4 
TIGER                             4             8
UWO                               1             4
                                ------------------
VISITOR INST. TOTAL              23            59

SCIENTIFIC TOTAL                 62           158

Visitor instrument use represents 37% of all scientific observing.

The average number of nights per visitor program is 2.51.

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Observing Schedule/Calendrier Des Observateurs


                                                                                             
   Date   Nights Observer    Program   Focus & Instrument    Short Program Title
noon-noon Nuits  Observateur Programme Foyer & Instrument    Titre abrégé du projet
midi-midi                                                                                      
                                                                                              

Aug 01-04 (1.5)Richer    C20      F8  MOS         Gas Fract. & Oxy. Ylds in Gal.
          (1.5)Richer    F16  
    04-06 (2)  Chambers  H09      F8  MOS         Comp. of 125 kpc Cloud at z=2.48
    06-08 (2)  Simard    C07                      F8  SIS Kinematics of Faint Bl. Gal. = II
    08-12 (4)  Morris    C22      F8  SIS         Evol. of Cl. Gal. fr. z=0.6-pres. 
    12-13 (1)  -         D01      F8  SIS         Discretionary
    13-14 (1)  -         E01      F8  SIS         Engineering
    14-15 (1)  -         E02      F8  RedeyeW     Engineering
    15-16 (1)  -         D02      F8  RedeyeW     Discretionary  
    16-19 (3)  Pello     F20      F8  RedeyeW     Ph. IR profonde dans 3 amas de gal.
    19-22 (3)  Yee       C13      F8  RedeyeW     IR Imag. of Gal. with Hi-Z QSOs
    22-24 (2)  -         E03      Cou Coude F/8.2 Engineering
    24-25 (1)  -         D03      Cou Coude F/8.2 Discretionary
    25-28 (3)  Bîhm      F08      Cou Coude F/8.2 Disques d'accrétion, ét. Ae/Be de Herbig?
    28-29 (1)  -         E04      PF  FOCAM       Engineering
    29-30 (1)  -         D04      PF  FOCAM       Discretionary
    30-02 (3)  Harris    C10      PF  FOCAM       St. Halos of Sp. Gal. M31 & M33
Sep 02-06 (4)  DeRoberti C21      PF  FOCAM       Srch for Signature of Primeval Gal.
    06-08 (2)  Fort      F09      PF  FOCAM       Shear grav. autour src rad.
    08-11 (3)  Lequeux   F24      PF  FOCAM       Transp. du disque et mat. dans M31
    11-12 (1)  -         E05      PF  FOCAM       Engineering
    12-14 (2)  Kunth     F43      F35 BEAR        Sp-Im Gal. bl. compactes
    14-17 (3)  Cox       F06      F35 BEAR        2 Micron Sp-Im. of Nebulea - cont.
    17-18 (1)  Maillard  F18      F35 BEAR        Sp-Imag. of Night Side of Venus
    18-20 (2)  Gerin     F46      F35 FTS         FTS HR Profiles of V=1-0 S1 Line
    20-21 (1)  Lellouch  F12      F35 FTS         Venus: dyn. mésosphère des infr. 
    21-23 (2)  Coustenis F15      F35 FTS         Surf. de Titan partir de sp. infr.
    23-27 (4)  Nadeau    C30      F8  MONICA      HS Res. Imag of H2 & FeII
    27-28 (1)  -         E06      F8  SIS         Engineering
    28-30 (2)  Jewitt    H05      F8  SIS         Activity in Distant Comets
    30-04 (4)  Pritchet  C09      F8  SIS         Fund. Pl. for Inter. Redshift Ell.
Oct 04-07 (3)  Luppino   H06      F8  MOS         Sp. of Gal. & Grav. arcs in  Gal.
    07-09 (2)  Lilly     C12      F8  MOS         Unbiased Sample of Gal. at z>1
    09-11 (2)  Barucci   F01      F8  MOS         Dark, Volatile-Rich Asteroids
    11-13 (2)  Herbig    H04      F8  MOS         Spectros. of Faint Stars in Y Cl.
    13-16 (3)  Cowie     H08      F8  QUIRC       Wide Deep IR Surv. with 1024 Array
    16-17 (1)  Hu        H10      F8  QUIRC       IR Imag of z>5 Gal. around HR qu.
    17-21 (4)  Bohlender C28      F8  UWO Pol.    Mag. Flds & Wind Var. in O Stars
    21-24 (3)  Monin     F30      F8  RedeyeN     Imag. IR de Néb. Protostellaires
    24-27 (3)  Welch     C32      F8  RedeyeN     Met. of M31 Ceph. Lum. in Near-IR
    27-30 (3)  Henry     F07      F8  MOS         Chem. Ab. Patterns in Cl. Spirals
    30-02 (3)  Azzopardi F22      F8  MOS         Etoiles de WR dans M31
Nov 02-04 (2)  Cabrit    F42      F8  TIGER       Etude en Spectro-Imagerie
    04-07 (3)  Rocca-    F64      F8  TIGER       Radiogal: Evol., Cin. et Cosm.
               Volmerange    
    07-09 (2)  Festou    F49      F8  TIGER       Répartition des zones de dégazage
    09-10 (1)  Ferruit   F59      F8  TIGER       Or. & Form. des amas stellaires
    10-14 (4)  Gies      C33      F8  GSU         Sp. Cam Speckle Sur. for Dup. Am. O Stars
    14-15 (1)  -         E07      Cou GECKO       Engineering
    15-18 (3)  Boesgaard H02      Cou GECKO       Beryllium in Lith.-Def. F Stars
    18-22 (4)  Hill      C05      Cou CF8         Abun. in A-type Stars in Pleiades
    22-23 (1)  -         E08      PF  -           Engineering
    23-26 (3)  -         E09      PF  MOCAM       Engineering
    26-27 (1)  -         D05      PF  MOCAM       Discretionary
    27-30 (3)  Fahlman   C25      PF  MOCAM       Mapping Dark Matter in Rich Gal.
    30-03 (3)  Bonnet    F27      PF  MOCAM       Profil de masse amas de galaxies
Dec 03-06 (3)  DePropris C08      PF  FOCAM       Study of Lum. Func. in Gal. Cl.
    06-07 (1)  -         E10      PF  FOCAM       Engineering
    07-10 (3)  Perrier   F65      F35 CIRCUS      Interfer. Imag. of Low Mass Bin.
    10-12 (2)  Giard     F50      F35 CIRCUS      PAHs dans les rég. de photodissoc 
    12-14 (2)  Rouan     F40      F35 CIRCUS      Str. à pet. échelle du mil. IS 
    14-17 (3)  Boulanger F28      F35 C10  Srch for YSO in Orion B
    17-18 (1)  Merlin    F63      F35 C10  L'ém. PAH à 8 et 11 dans NGC7027
    18-19 (1)  Monin     F34      F35 C10  Protost. Srcs in Molecular Cores
    19-22 (3)  Roddier   H07      F35 IfA AO      Inv. of T-Tau Ob. using AO System
    22-23 (1)  -         D06      F35 IfA AO      Discretionary
    23-24 (1)  -         D07      F8  SIS         Discretionary
    25-27 (2)  Bridges   C14      F8  SIS         Gl. Cl. Form. in Merg. Galaxies
    27-29 (2)  Garnavich C29      F8  SIS         Radio Sel. Grav. Lens Candidates
    29-30 (1)  Crotts    C35      F8  SIS         Echoes & Lt-Time Ltcurve SN1993J
    30-01 (2)  Stockton  H11      F8  MOS         Sp. of Ext. Str. Ar. ~1 3CR Qu.
Jan 01-04 (3)  Hanes     C15      F8  MOS         Gl. Cl. of SO Gal. NGC3115
    04-06 (2)  Ellingson C19      F8  MOS         Redshift Sur. in Qu. Fields
    06-09 (3)  Crawford  F05      F8  MOS-ARGUS   Two-dim. Sp. of bl. lt in Cl. Gal 
    09-10 (1)  -         D08      F8  MOS-ARGUS   Discretionary
    10-11 (1)  -         E11      Cou GECKO       Engineering
    11-14 (3)  LandstreetC17      Cou GECKO       Line profiles of A&B Stars
    14-16 (2)  Lemoine   F55      Cou GECKO       Rapport Isotop. du lithium
    16-17 (1)  -         E12      F8  RedeyeW     Engineering
    17-18 (1)  -         D09      F8  RedeyeW     Discretionary
    18-21 (3)  Eales     C16      F8  RedeyeW     Inv. of Gal. Ar. 1.4

Requests for observing time on the Canada-France-Hawaii Telescope
are made to the member agencies.  There are two competitions per
year--one for the first semester (February-July) and the other for
the second semester (August-January).  The mailing addresses and
deadlines for proposal submission are given below for each of the
three agencies.

                              CANADIAN AGENCY

                   Canadian Applications Committee CFHT
              c/o Director Herzberg Institute of Astrophysics
                     National Research Council Canada
                        100 Sussex Drive, Room 2003
                              Ottawa, Ontario
                              CANADA K1A 0R6

NOTE:  One original, six [not FAX] copies.

                       DEADLINES (Date of receipt):
                 For time in first semester - September 1
                   For time in second semester - March 1



                               FRENCH AGENCY

                Institut National des Sciences de l'Univers
                              M. le Directeur
                            3, rue Michel Ange
                                 BP 287-16
                           75766 Paris Cedex 16
                                  FRANCE

                       DEADLINES (Date of receipt):
                 For time in first semester - September 1
                   For time in second semester - March 1



                           UNIVERSITY OF HAWAII

                                 Director
                          Institute for Astronomy
                            2680 Woodlawn Drive
                          Honolulu, Hawaii  96822
                                  U.S.A.

                       DEADLINES (Date of receipt):
                 For time in first semester - September 1
                   For time in second semester - March 1

Les demandes de temps d'observation avec le Télescope Canada- France-Hawaii doivent être soumises aux agences associées. L'attribution de temps, sur une base compétitive, est effectuée deux fois par année: une fois pour le premier semestre (février à juillet) et une fois pour le deuxième semestre (août à janvier). Les adresses postales et les délais de soumission sont indiqués ci- après pour chacune des trois agences.

                             AGENCE CANADIENNE

                      Comité canadien de demandes CFH
                            c/o M. le Directeur
                     Institut Herzberg d'astrophysique
                   Conseil national de recherches Canada
                        100 Sussex Drive, Room 2003
                              Ottawa, Ontario
                              CANADA K1A 0R6

A noter:  Un original, 6 copies - pas de FAX.

                    DATES LIMITES (date de réception):
                 Pour le premier semestre - 1er septembre
                   Pour le deuxième semestre - 1er mars


                             AGENCE FRANÇAISE

                              M. le Directeur
                Institut National des Sciences de l'Univers
                            3, rue Michel Ange
                                 BP 287-16
                           75766 Paris Cedex 16
                                  FRANCE

                    DATES LIMITES (date de réception):
                 Pour le premier semestre - 1er septembre
                   Pour le deuxième semestre - 1er mars


                            UNIVERSITE D'HAWAII

                                 Director
                          Institute for Astronomy
                            2680 Woodlawn Drive
                          Honolulu, Hawaii  96822
                                  U.S.A.

                    DATES LIMITES (date de réception):
                 Pour le premier semestre - 1er septembre
                   Pour le deuxième semestre - 1er mars

The Canada-France-Hawaii Telescope Corporation (CFHT) is a joint organization of the National Research Council of Canada (NRC), the Centre National de la Recherche Scientifique of France (CNRS), and the University of Hawaii (UH). The CFHT Information Bulletin is published twice a year in January and July. It is distributed free to Canadian, French and Hawaiian astronomical institutions and to others interested in astronomy. Text and illustrations may be reprinted if credit is given to: CANADA-FRANCE-HAWAII TELESCOPE CORP., P.O. Box 1597, Kamuela, Hawaii 96743 USA, Telephone: (808) 885-7944. Fax: Waimea (808) 885-7288 and Summit (808) 935-4511. Questions and comments about the Bulletin should be sent to the attention of Dr. Robin Arsenault at CFHT.

La Société du Télescope Canada-France-Hawaii est une organisation conjointe du Centre National de Recherches du Canada (CNRC), du Centre National de la Recherche Scientifique (CNRS), et de l'Université de Hawaii (UH). Le Bulletin d'Information du télescope CFH, publié 2 fois par an en janvier et juillet, est distribué gratuitement aux instituts de recherche astronomique canadiens, franáais et hawaiiens et sur demande à toute personne intéressée. Les textes et illustrations publiés peuvent être reproduits à condition d'en mentionner la provenance: CANADA- FRANCE-HAWAII TELESCOPE CORP., P.O. Box 1597, Kamuela, Hawaii 96743 USA, Télephone: (808) 885-7944. Fax: Waimea (808) 885-7288 and Summit (808) 935-4511. Questions et commentaires à propos du Bulletin sont à envoyer à l'attention de Robin Arsenault au TCFH.

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durand@dao.nrc.ca