COMMENTS ON THE USER COMMITTEE MINUTES Medium Resolution Gratings With luck, these could be installed by 4Q97. They will probably replace permanently the current low dispersion set since there is no easy way to switch out gratings at night. Programs in progress requiring the current low dispersion gratings should be identified to make sure they can tolerate the new gratings. DIS Noise & the Two-Peaked Histogram The two-peaked histogram in the red chip is still present, and whatever causes it is probably causing the high read noise of 21 electrons (reported by Karen Gloria). The best this chip can deliver must be around 15 electrons, however, so unless this difference is preventing science, I'd suggest spending time looking for new detectors instead of trying to squeeze more performance out of these. DIS UV Throughput Fix I'd like to delay this operation into the 3Q98 because I can't guarantee a reasonable schedule this year. The incentive to fix in parallel an "overall throughput decline" is lower since I suspect the reason for this was the telescope, not the spectrograph (but if anyone has other thoughts, I'd like to know). Alan Uomoto April 16, 1997 APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 140 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