Minutes to APO 3.5m User's Committee Phone Conference, December 11, 1995 Michael Strauss Attending: Alan Uomoto, Julie Lutz, Bruce Gillespie, Ed Turner, Lew Hobbs, Michael Strauss, Rene Walterbos, Chris Stubbs The following is an e-mail from Bruce Gillespie describing the current status of systems at the telescope, with additions based on the discussions held. Board of Governors annual meeting- Approved 1996 Operations Budget at $510K, plus funds for replacement 2ndary mirror ($250K) and continuing engineering support. The board understands that we don't have a hard cost on the 2ndary, and we might have to come back to them for more (we're planning to get started on this fast). Deferred hiring of programmer. Telescope- Telescope has generally worked well during the three weeks since the shutdown. Pointing is ~4 arcseconds rms, blind tracking OK for few tens of minutes, and now the offset guider now is working fairly routinely. Pointing accuracy seems to be a function of rotation of secondary. Seeing and image quality generally near 1 arcsecond (not that good with DIS). ChAOS measurements made by Kibblewhite's team indicate that 20Hz image motion reduced, but still show evidence of harmonic motion at other frequencies at amplitudes of few tenths arcseconds--work continuing on tracking down and fixing this. A "breathing mode" is seen on ~1 Hertz, due to primary mirror support hydraulics? Short exposure image (0.1 sec) taken recently has FWHM of ~.6 arcseconds (this was on a night with good seeing with longer exposures, around 1"), consistent with Hartmann and profilometry data. Also 0.7" seeing seen on GRIM evening of December 10. Stubbs: Are we 100% sure that the secondary is indeed the cause of the poor seeing? That is, are we sure that we should have it refigured? We should be so before we commit ourselves? Tests could involve rotating the secondary 90 degrees, which would take of the order of a week. In any case, we would not be committed monetarily until summertime. Strong feeling of the user's committee that one more confirmation is needed that it is indeed the secondary before committing ourselves. Enclosure drive working well since shutdown, cracked wheel problem under discussion with original manufacturer, L&F Industries; perhaps we can get them to fix it. We've put the idea into their heads; they will get back to us. Another ultrasound soon will tell us how long before these wheels get critical. S/W and Remote Observing- New version of Remark baselined, handles 512^2 guider chip correctly. Network quality and bandwidth about the same as usual, being monitored. Considering extending grace period of data transfer (at the moment, one has 36 hours to transfer data before it is erased). We probably have enough disk to get away with this. One possibility is that we have a setup like at Keck or KPNO; all data taken are spooled to tape stored at APO every morning. Stubbs: Aggressively investigate what is required for us to make backup copies of all observations at the site: everyone agreed. No progress reported on getting SLIP modem capability in place at remote stations (not quite true: Princeton has been able to do this!). Instruments- DIS is performing nominally, a new calibration spectrum atlas is under construction and will be placed on the web server when completed. Andy Silber (UWash) has developed a slit-view CCD (300x400) camera, which was installed on DIS two weeks ago and tested. In ~1m exposures, detects 19th magnitude objects, but has vignetting and scattered light problems which are being solved, should be operational in a few weeks as a user facility. GRIM2 is working well, a reported fix in the exposure time problem reported recently on the Princeton mail exploder. Echelle, HRI; no report. DSC is expected to return to APO next week, having had its dewar (and CCD) cleaned and leak-tested, plus electronic repairs which are expected to solve the noise and latent charge problems. No filter wheel, as far as Bruce knows. ChAOS has been used recently in stand-alone mode, some spectacular results reported. Laser beacon system being installed at right Nasmyth, first "beacon" scheduled for next weekend (a great deal of government approval is needed to shoot lasers into the air). AMBER camera installation has begun, should continue and be completed in January. Guider- When shutter for 1024^2 Spectrasource CCD guider failed, replaced camera with 512^2 camera (which is a backup and also intended for manual guiding for the Echelle). Eric Deutsch updated the guide star finding utility on the web server to work for the smaller format camera. 512^2 camera had been previously "rehab'd" by the vendor, and as a guider works very well. Sensitivity is good enough to close guide loop on ~17th magnitude objects. In the richer fields, guide stars can be found almost at random. This leads to optimism that the 1024^2 camera can be repaired and successfully used (this may be enough to give a guide star in any field at any PA; if not, we could put a field lens in front to get another factor of four in field). Stubbs et al have an engineering run this week to characterize this well. Camera is being shipped to Spectrasource this week for evaluation and repair. They may actually change the 1024^2 chip. Feedback from users is needed on how the guider is working. Calibration Systems- Have received new Xenon and Krypton arc lamps. Down-pointing lamps have been in use for three weeks, exposure times are shorter and now not necessary to open/close enclosure shutter to take calibrations (still have to manually open/close mirror covers). Have h/w to now install three types of arc lamps plus two white light sources simultaneously, will do this week. Still have to determine uniformity of calibrations, and baffling of scattered light. Plan to add Calibrations page to web server home page shortly. A real worry is that the line centers seem to shift depending on which such lamp is on (a fraction of a pixel is the amplitude of the effect). Flats are also not as reproducible as we would hope, depending on rotation of the spectrograph. More efficient baffling would solve this latter problem. In the meantime, there is a recommendation to take flats over a range of rotation angles, and average the results. All-sky camera- The 10-micron all-sky camera is run routinely by the Observing Specialists, and Eric Deutsch has written a utility that extracts the images, does some reduction, and posts these on his web page: http://www.astro.washington.edu/deutsch/apoinfo/cloudscan/latestimage.html . A pointer to this has been added to APO's weather web page--observers can keep tabs on the sky at APO in near real-time. ***********END OF GILLESPIE'S E-MAIL**************** Schedule for next quarter will be out December 15. Questions for User's committee from Board, to think about: 1. Which instrument should JHU build once they become full participants? 2. Echelle and HRI: Chicago is about to make one further attempt to get the Echelle going. They are way over the original budget, so if they fail, they will ask the collaboration to share the costs in this. Another question: should the HRI be abandoned? Everyone agrees that the DSC does everything that this would do. Chris Stubbs is thinking about making a 2048^2 chip into an imager with a big field; this plus the DSC will cover all the science drivers of the original HRI. The HRI is on indefinite hold at Chicago anyway (all the effort is going into the Echelle). User's committee has no objection to dropping the HRI. An agenda item for next time, from Stubbs: Each institution give a prioritization of the developmental, enhancement tasks to be done (improving baffling, improving calibrations, upping observing efficiencies). Further discussion of how things get fixed once problems are noted. Next meeting is January 8. APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 31 in the apo35-general archive. You can find APO the archive on http://astro.princeton.edu:82/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