Hello, It appears the time has come once again to remind our observers they should be logging in at least an hour before the start of their scheduled observing time. This applies in particular to first-half observers, especially DIS users. The order in which we like to do things on a promising evening is as follows: telescope and instrument checkout, then DIS cals or SPIcam biases, as needed. Then we can open the dome, which is ideally done a good half hour before sunset to allow time for cooling. Twilight flats with GRIM or SPIcam can start as early as five minutes after sunset, depending on the filter. It is dark enough to start focusing somewhere around 15-20 minutes after sunset, and dark enough to observe a standard star after that. That brings us approximately to the end of 12-degree twilight and the official start time for the program. On a good night, more than an hour of important work gets done before the time listed on the schedule. Observers who don't log in until their scheduled start time, or just a few minutes before their start time, will be losing dark sky to tasks that could have been done in twilight (focusing, standards, in-dome cals). In addition, if the dome is kept closed through sunset to allow darkness for cals (DIS cals in particular), this costs valuable cooling time and degrades image quality when the observer is finally ready to get on the sky. We also appreciate having observers log in a little early if they are scheduled for second half. Remember that the instrument change time shown on the schedule is a worst-case scenario; you may well be able to start earlier than it says on the schedule. The first half observers may also give up early due to borderline conditions, or perhaps because they can't make use of an exposure shorter than half an hour. Lastly, it's nice to know that the second half observer is awake and ready to go, so that we don't have to wonder if we should start looking for a replacement for a no-show. Remote obseerving at APO is easier than travel to a national observatory, but we would like it to be treated with the same seriousness and advance preparation. Thanks for you cooperation in this matter. Russet McMillan APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 618 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