APO 3.5-m Users Committee Phonecon, 9/17/07 Attending: Suzanne Hawley, Bruce Gillespie, Mark Klaene, Scott Anderson, Remy Indebetouw, Ed Turner (for Michael Strauss), Russet McMillan, John Bally, Bill Ketzeback Absent: Jon Holtzman, Al Harper, Jon Fulbright Minutes taken by Bruce Gillespie ********************************** User feedback, comments from institutional representatives: Princeton (Turner) - Ed said that Michael Strauss told him he had no user comments to share. Since much of the time since the last meeting was during the summer shutdown, we would naturally expect there to be little user feedback. UVa (Indebetouw) - Remy had nothing to report, other than UVa is organizing a site visit for their students this fall. Russet and Suzanne mentioned that we will be hosting four separate student site visits at APO in the coming weeks. UW (Anderson) - Scott had no user comments, and Suzanne mentioned that Paula Szkody thanked us for getting some guider images of a target that is scheduled for upcoming HST observations. CU (Bally) - John had no user comments to report. JHU (Fulbright) - No report UChicago (Harper) - No report NMSU (Holtzman) - No report ********************************** Discussion of telescope/instruments report - Klaene: The report is given below; Mark walked through the highlights, and there was some discussion. The summer shutdown started and finished on schedule, and the telescope and instruments are good-to-go for science observations. Nick McDonald, the recently hired 3.5-m telescope engineer, was given responsibility for most of the shutdown activities, with help from several others. Nearly all the tasks were completed (see list below), and the leftovers will be attended to in the coming weeks. One of the small scallop cracks in the back of the primary mirror faceplate seems to have gotten somewhat larger, and as a precaution the mirror support at that cell has been disabled. No discernible effect on the optical performance of the mirror has been detected. The PMSS was serviced and calibrated, and the instruments were all serviced except the echelle (which is serviced every two years). There may be a lingering problem with the DIS cryotigers that could require attention later this year, although they appear stable at the moment. Except for NIC-FPS, all the instruments (including CorMASS and GFP) are up and ready for use. Suzanne recently visited Kitt Peak while our mirror was there, and she mentioned that the mirror looked pretty good even before it was realuminized. Mark said that the exact before/after improvement in reflectivity numbers is not yet available, but there was an indication that the reflectivity before recoating was ~91%, and only went up to ~92% afterward. The scattered light from the surface did improve a factor of 10, from ~2% to about .2%. This indicates that we are doing a pretty good job of keeping the mirror clean in the telescope for relatively long periods of time. Russet said that some observers take calibrations off the scattered light from the primary mirror, and that they will need to increase their exposure times accordingly. The DIS grating mounts were given new larger bushings to help protect the gratings during changes. Also, the red-high grating has been shimmed to place the spectrum near the center of the detector. Suzanne asked if users had been having problems with the red-high spectrum placement in the past, and Russet said that some users had mentioned it during instrument checkout, but nobody had reported problems with data reductions. With the spectrum now better positioned, the stray light from the on-chip amplifier glow is less of a problem. ************************* 3.5-m Telescope, Instruments, and CIF Projects Highlights, 8/18/07 through 9/12/07 Mark Klaene 0) Overview Monsoonal weather continued with moderate rain and evening clouds, which limited most of the on-sky time that would have been available for science observing. However, the shutdown started near the beginning of the reporting period, so little scheduled observing time was lost. Wet weather continued through the shutdown, but we were largely able to work around it. Construction started on the SDSS Support Building expansion project (for AS2) with no disruption to 3.5-m work. 1) Telescope The shutdown started on time and remained ahead of schedule for much of the period. Weekend work was performed but limited in scope. To date all of the shutdown tasks (see list below) were completed except: o the Echelle fans have not been changed since the wrong parts were delivered, and o the new instrument rotator axis controller system was not tested on the telescope. There were a few problems noted but none were particularly surprising. The primary mirror cracks were inspected and were seen to have stayed basically unchanged except for the top of cell A3--the load cell for this support has been clamped off to relieve stress at this mirror position. Loose flex pivots were noted on the tertiary mirror support and repaired. Fifteen rivets were found to be loose and were replaced on the primary mirror covers. The mirror covers were repainted and we anticipate higher overall cal lamp throughput as well as a noticeable improvement between 350 and 400 nm. The new instrument rotator assembly was fit tested and aligned but could not go in to service due to continued work needed on the axis controller software. 2) Instruments o The bushings were replaced on all DIS grating holders and the gratings were realigned. This should reduce the risk of grating damage when installing gratings, especially in cold weather. The red- high grating was moved into another mounting cell and a shim was made to position the spectrum on the middle of the chip; o Both DIS cameras were evacuated and the cryotiger lines cleaned. The red cyrotiger compressor was replaced. Contamination was found in both sets of cryotiger lines; o SPIcam was evacuated and baked out; o NIC-FPS remains at CU for 16-channel readout and etalon upgrades. We expect its return to the site in early October; o CorMASS was evacuated and cooled down; and o GFP was evacuated and cooled down. Summer Shutdown Task List M3: Realuminize, service actuators M1: Realuminize, check and photograph cracks PMSS: Pressure transducer calibration, load cell calibration, bellofram inspection leak check, air line leak check with belloframs by sector, servo valves inspection/cleaning, clean mirror cell, vent tube repair, foam inspection, mirror cover actuator inspect and service, calibrate LVDTs, investigate fore/aft mirror constraint Mirror covers: Repaint covers, repair rivets Pump SPIcam Pump DIS: Purge/recharge blue cam cryotiger system, install new bushings in grating holders, remount DIS red-high grating in new holder Replace UPS batteries: Echelle, Inst - I level, Elect I -level, #3 for ops bldg Echelle electronics fan replacement (not completed) New instrument rotator axis controller (not completed) New NA2 rotator assembly Repair strain gauge metrology noise issue (not completed) Replace temperature sensors on primary mirror Repair secondary mirror accelerometer recording system ********************************** Wide-field NIR instrument - Hawley, Gillespie: Suzanne reported that we have received a second proposal from a non- ARC astronomer (the original proposal was made to us about 18 months ago) to build a wide-field NIR camera and grism spectrometer with a 13-arcminute FOV and a programmable slit mask, and bring the instrument to the 3.5-m for their and our use. This could be done in exchange for telescope time much like the arrangements we have used with CorMASS and the Goddard Fabry-Perot instruments; other collaborative scenarios are possible. Several of the Users Committee members expressed strong support for continuing to pursue this initiative, and commented on how such an instrument would complement NIC-FPS and further our interests in general NIR science capabilities. We need to determine a sense of how much ARC user interest there would be in having access to this instrument at APO before expending significant time or money on our side. Users can check with their committee representatives for additional technical information about the instrument. ACTION: Users interested in a wide-field NIR camera at APO should send a paragraph or two to their Users Committee representative with copies to Suzanne and Bruce with an expression of interest and/or questions regarding this proposed instrument. ********************************** NIC-FPS status - Bally: John reported that the NIC-FPS etalon has undergone multiple cryo cycles, and that the oscillations seem to be cured. However, an accident happened two weeks ago involving the power supply and etalon motor controllers, which resulted in the need to replace the controllers, which will cause a delay in returning the instrument to APO. Suzanne said that a new Q3 schedule, sans NIC-FPS, will come out shortly, and NIC-FPS will not be listed as available in Q4 until 20 October. The replacement controllers have been received in Boulder, and the instrument will be bench-tested with the 16-channel detector upgrade and etalon in a few days. The science-grade and engineering-grade chips have been modified to allow the 16-channel reads, which will enable more efficient observations with Fowler sampling, and the electronics have been modified to reduce system noise. Software work is underway both at CU and at APO to process the 16-channel reads, and to provide quick-look images during observing without excessive processing overheads. ********************************** Tertiary tip-tilt decision - Hawley: Suzanne said that a decision was taken not to include tip-tilt capability into the new tertiary mirror support system, which is about to be designed. The decision process used, which seemed to work and converge well, was to form a committee, solicit user input, examine existing tip-tilt systems on other telescopes, and look at existing telescope and site-intrinsic seeing data, to determine if tertiary tip-tilt should be a high priority for the 3.5-m telescope. Based on these evaluations, we will make fast guiding and auto-focus (using the existing NA2 guider) our near-term priorities. If tip- tilt is determined to be needed in the future, we will employ the tip- tilt design hooks inherent in the new 2ndary mirror mounts. ********************************** Science Highlights from '07 - Hawley, Gillespie: This is the time when we prepare the annual report for the ARC Board of Governors meeting. One or two science highlights (text, graphics, images) of one or two pages for each highlight are traditionally presented in the report and orally to the Board members. ACTION: We need each institution's Users Committee member to poll their users and send these highlights to Suzanne and Bruce, not later than 15 October, for inclusion in the report. For obvious reasons, we would like to have at least one representative user science highlight for each ARC institution. ********************************** Actions from earlier meetings - group [open from previous months]: ACTION: Suzanne said that the Users Committee members need to identify which of their users would be willing to contribute effort and participate in a telecon to scope tip-tilt for the 3.5-m, and to communicate their names to her and Bruce Gillespie before 30 July. STATUS: Completed (see above), closed. ACTION: Jon Holtzman will investigate and report on the tip-tilt system at the TNG telescope on La Palma. STATUS: Completed (see above), closed. [new actions from this month]: ACTION: Users interested in a wide-field NIR camera at APO should send a paragraph or two to their Users Committee representative with copies to Suzanne and Bruce with an expression of interest and/or questions regarding this proposed instrument. ACTION: We need each institution's Users Committee member to poll their users and send science highlights (since Oct. '06) to Suzanne and Bruce, not later than 15 October, for inclusion in the annual report to the ARC Board. ********************************** Next meeting: The next Users Committee phonecon will be on Monday, 15 October, at 8:30 AM Pacific Time. The agenda and other materials will be sent to the committee members during the preceding week. APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 1058 in the apo35-general archive. You can find APO the archive on http://www.astro.princeton.edu/APO/apo35-general/INDEX.html APO To join/leave the list, send mail to apo35-request@astro.princeton.edu APO To post a message, mail it to apo35-general@astro.princeton.edu APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO