The report by Ledlow et al suggests that there has been a factor of 2 drop in throughput in DIS over the last two years. The Princeton group, under Ed Turner, has been obtaining images of the same fields repeatedly over that period; th subset of those data taken under photometric conditions should be adequate to test this drop in throughput directly (if it is not connected to the gratings themselves somehow). -Michael Strauss APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 16 in the apo35-dis archive. You can find APO the archive on http://astro.princeton.edu:82/apo35-dis/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-dis@astro.princeton.edu APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO