CFHT Board of Directors - December 2001

Data Access Policy

1. The CFHTLS is based on the concept that all members of the CFHTLS community (defined below) have equal access to the raw and pre-processed images obtained at the telescope and to the subsequent advanced data products produced by the Terapix and CADC processing centers (collectively referred to as the CFHTLS data).  Access will be via registration as a Registered User (defined below).

2. The raw and pre-processed images, and later the advanced data products, will be made available to all Registered Users simultaneously. Individuals responsible for pre-processing and releasing the CFHTLS images will not undertake science analysis in advance of the release to the CFHTLS communities.

3. The CADC shall serve as the primary distribution center that provides general community access to the data.  The CFHT and Terapix may retain private copies of locally produced data for use by their respective scientific staff. Such private data will be identical to that provided to the community through the CADC, and will not to be distributed outside these institutions.

4. The standard image data available for general community distribution will be the pre-processed images produced by the CFHT-NOP data system. Unprocessed (raw) images will be available from the CADC upon request, but generally not before the pre-processed images are released to the CFHTLS community.  Release of the pre-processed data will occur as soon as possible after observations and it is anticipated that there will be a release of all of the data from an observing run no later than one month after the run.

5. The raw and pre-processed images will be proprietary within the CFHTLS community for a period of 13 months after the end of the semester in which the data was acquired, and thereafter released globally by CADC in the usual way.

6. Registered Users agree to protect the proprietary rights of the CFHTLS community by individually not exporting proprietary images to persons other than Registered Users or of making public the data in digital form.

7. The export of CFHTLS proprietary images to external members of a scientific collaboration is permitted only upon the explicit authorization from the CFHT Executive Director, upon advice from the CFHTLS Science Steering Group.

8. The advanced data products produced at the Terapix and CADC processing centers, including catalogues and optimally processed and stacked images, will be proprietary for one year after release within the CFHTLS community.

9. The results from all scientific analyses of CFHTLS data are the exclusive property of the individuals responsible for the analyses and may be published in any form at any time in the usual way.

10. The CFHT Executive Director, acting upon advice from the CFHTLS Science Steering Group, may authorize the installation of near real time analysis systems (RTAS's) at the CFHT base facility in Waimea.  Such RTAS's must have limited and clearly stated scientific goals. The fundamental criterion for installing (or maintaining) an RTAS is that follow-up observations are required before results can be obtained from the anticipated general release date in order to achieve a stated science goal.

11. It is understood installed RTAS's may access the data only for the purpose of achieving their stated scientific goals. Images accessed by the RTAS's may not be copied to any transportable media nor exported from the CFHT site by any means.  In the case of the RTAS's, it is anticipated that there will be co-operation and collaboration between groups in the participating communities in the dissemination of detected objects.

12. Users of CFHTLS data should include an acknowledgement in all publications as follows:

This work is based in part on data obtained as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of the National Research Council of Canada and the French Centre national de la recherche scientifique.

Users of the advanced data products should include an acknowledgement in all publications as follows:

This work is based in part on data products produced at the Canadian Astronomy Data Centre and Terapix as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of the National Research Council of Canada and the French Centre national de la recherche scientifique.

Explanatory Note: The CFHTLS community of registered users

The CFHT Executive Director is charged with administering a system of registering eligible persons to become users of the CFHTLS data. In general, only registered individuals will have access to the proprietary CFHTLS data.

The eligibility of individuals to receive proprietary access to the CFHTLS data is extended to:
· All persons engaged in astronomical research residing in France and Canada (includes students and post-doctoral fellows as well as employed professional astronomers as Universities and Research Institutes).
· Members of the CFHT scientific staff.
· Professional astronomers employed at Research Institutes or Universities outside of Canada or France, but who are directly or indirectly supported by either NRC or CNRS, or another French or Canadian agency (e.g., a French Astronomer at ESO, a Canadian astronomer at JAC).

Individuals who do not fit the stated eligibility criteria but nevertheless believe they may be eligible to be included in the CFHTLS community may apply, stating their argument,  to the CFHT Executive Director for authorization to register.

Previously registered users whose status changes to one that no longer fits the stated eligibility criteria will normally be removed from the list of authorized users (their registration will be revoked). Such individuals may appeal to the Executive Director, stating their reasons to continue as a registered user of the CFHTLS.


The registration form will contain a statement of the obligations associated with access to the data, especially regarding the proprietary nature of the data (i.e. (6)-(8) above), and the requirement of an acknowledgement (12).