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Excellent Progress with NIRI Flexure; Update on Acceptance Tests, Queue and System Verification Observations
26 September 2001
We recently completed flexure tests for NIRI using the new redesigned camera steering mirrors. We are very pleased to report that the flexure measured between the input focal planeand the detector is now at the sub-pixel level for all cameras and all possible gravity vectors for NIRI on the telescope. The little flexure remaining is very repeatable and typically has the sinusoidal behavior expected for "real" flexure (not steering mirror motion). Additional flexure tests in preparation for observing using targets on the sky will be performed as part of acceptance testing in October 2001.
Regularly scheduled NIRI science operations are scheduled to begin after the acceptance tests are successfully completed. A significant number of nights have been allocated for NIRI observations throughout the rest of semester 2001B, although some of those nights will be needed for additional System Verification observations. We anticipate completing a significant fraction of the NIRI wide-field imaging programs that have been awarded time, especially those in scientific ranking bands 1 and 2. The ability of NIRI to produce scientifically useful data has been demonstrated in wide-field imaging mode during the System Verification observations conducted in May. The SV data are currently being assessed and procedures for reducing the data refined. The NIRI package of IRAF tasks for reducing the imaging data is now complete, and we anticipate release of the first NIRI SV data in mid-October. The performance of the NIRI Integration Time Calculator was checked using these data.
NIRI observations in the other modes (high-background thermal imaging, low-background and narrow-band imaging, and grism spectroscopy) will also be attempted during the coming months. These modes have not yetbeen verified, and some additional commissioning work will need to be completed before we can begin science observations in these modes.
The newest version of the Observing Tool (OT) will be released during the first two weeks of October. The OT is used to prepare the Phase II observing programs. Some astronomers with accepted programs for semester 2001B will be asked to prepare their Phase II programs starting in October.More information on how to prepare Phase II programs will be coming shortly. Deadlines will be staggered depending on observing mode and rank.
Thank you all for your patience during the process of getting NIRI accepted, commissioned, and ready for use. More commissioning work will still need to be done to make NIRI fully operational in all observing modes and using the telescope high-level software. We are confident that we will get excellent data this fall, but caution that our efficiency will not yet be as high as we would like. Please keep in mind that we are still in the "shared risks" observing mode, both for NIRI and telescope systems. Programs in the Gemini queue are not carried forward from semester to semester (by Gemini--the national TACs may choose to do so). Therefore, proposers with currently accepted programs for semester 2001B should consider resubmitting programs for 2002A if the chances of execution are low. The probability of execution is greatest for near-IR wide-field imaging in the top two science ranking bands. Challenging thermal or spectroscopic observations will be less likely to be successful during 2001B, but highly-ranked proposals are likely to be attempted. Now that the image motion problem is solved, we will proceed to commission these modes as soon as possible, but we have not yet verified these modes. We should be executing these types of programs routinely during 2002A. Please note that observations using narrow-band filters that have not yet arrived (as listed on the NIRI web pages) will not be possible during 2001B, but may be for 2002A.
Hopefully this information will help you to plan your observing strategy for the next semester. Thanks once again for your patience. Please submit any questions you may have through the Help Desk so that information can be appropriately distributed.
Last update Sept. 26, 2001 by Joe Jensen