APO 3.5M SHUTDOWN FURTHER EXTENDED Unfortunately, it is now necessary to extend the shutdown of the 3.5m by an indefinite number of days. Science operations should be considered canceled until you are notified otherwise. Said notification will be issued at least 24 hours in advance, through both general electronic broadcast channels and email directed to the most immediately affected PIs and observers. This message is also being distributed in this manner. Schedulers, please do your best to bring these messages to the attention of your affected colleagues. The primary reason for this extension is delays caused by severe winter weather at APO. Heavy snowfall has made access to the observatory difficult and time consuming, though staff members have managed to reach the site each day. More seriously, extremely cold temperatures in the enclosure, ranging from single digits to the 20's, have greatly slowed progress on re-assembly of the telescope optics. There is extensive frosting within the enclosure, including exposed optical surfaces (but not the primary). Moreover, safe handling of delicate optical and mechanical components in such difficult working conditions requires going slowly and carefully. Furthermore, once re-assembly of the telescope is accomplished, approximately 1.5 clear nights on the sky are needed to re-establish alignment, a pointing model, focus settings, instrument blocks and so forth. If photometric conditions prevailed during this period, it would also be very desirable to make some initial post re-aluminization throughput measurements. Unhappily, though the recent storm has moved east, another front is expected at the end of the week with more snow and severe weather forecast for the weekend. Thus, it appears likely that the telescope cannot be available for science use until sometime next week, or possibly longer if there is a siege of bad weather. [Of course, science observations would be impossible anyway during such weather, so the time lost to the shutdown is inflated somewhat artificially. Baring unhappy surprises, the *useful* time lost to this extension will be only 1 to 2 nights, even if a much longer period of calendar time elapses.] In these circumstances, it appears more reasonable to extend the shutdown until further notice than to continue to do it in small increments of one or two nights. Ed Turner APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 114 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