The time of year has come around again when we must remind observers that it's desirable to log in early for first-half time. This is especially true for DIS users who take cals in the evening. Because the dome must be closed for DIS cals, they should be taken as early as possible in order to allow the dome to be opened for cooling. Right now we have many DIS observers who don't even log in until well after sunset, when it's almost dark enough to focus the telescope. It's desirable for the dome to be open at least half an hour before focusing; otherwise you'll be get poor seeing and rapid focus changes for the first few hours of observing. By waiting so late to do cals, observers are losing on-sky time and degrading their image quality. For DIS observers with first-half time, I strongly recommend logging in to take cals at least an hour before the end of twilight. When your cals are finished, the dome can be opened for cooling, and there will be time to take a break and get some dinner before focusing. If scheduling conflicts make it impossible for you to take cals early, please notify the observing specialist of when you will be logging in. The dome can be opened for a cooling period before sunset, then re-closed for your cals, and this will still aid in cooling the telescope. Russet McMillan. APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 505 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