CFHT Information Bulletin Number 37, Semester 97II

Optics Group Report

Greg Barrick, CFHT (


After many months of tracking down increasingly smaller light leaks, the MOS and OSIS spectrographs have been made light-tight. This was accomplished by the additions of bellows between the camera boxes and the grism boxes, replacement of missing screws from various locations, addition of opaque tubing on the nitrogen purge fitting, and addition of a seal between the grism boxes and the octagon. The result has been the capability of taking >90 second dark exposures with dome lights (or greater) with no perceptible light appearing on the STIS2 detector for both MOS and OSIS.


An auto-focus detector head has been found that will allow auto- focus to be implemented on the LAMA machine. The detector head uses a near-IR laser diode for its light source which is in a wavelength region in which the mask material is reflective. Previous detector units were unsuitable since the masks absorbed most of the light from the visible lasers that these units used. The detector and focusing stage are scheduled to be installed and operational by the November MOS run.


OASIS has arrived at CFHT and has been assembled and tested on the Mezzanine and on the telescope. The June engineering run was unsuccessful due entirely to bad weather. Despite the weather, the time was well spent and the instrument appears to be working very well. The next sky time scheduled for OASIS is in August.


The Gumball upgrade project is proceeding well. The optical design has been finalized and the optics have been ordered. With the exception of the etalons for the Fabry-Perot calibration source, all of the optical components have been received. The etalons are expected in early September. The mechanical design for the changes to be made is underway now and the electrical design and implementation for the new control system is progressing in parallel. The upgraded system should, hopefully, be in place and operational by the November MOS run.

CFHT Information Bulletin Number 37, Semester 97II
Copyright © 1997, Canada-France-Hawaii Telescope