MDM Observatory 2.4m Telescope Observer's Report for 2004 Sep 13

Observer(s): Paust
Institution(s): Dartmouth

Instrument: Echelle

Worked for 8 hours (all night)
Conditions were Photometric most of the night.
No equipment or software problems were encountered.

Seeing and Weather:
   High Winds all night.
   Beg: Seeing 1 arcsec, Clear, Winds High
   Mid: Seeing 1.7 arcsec, Clear, Winds High
   End: Seeing 1.7 arcsec, Clear, Winds High

Observing Summary:

There wasn't a cloud in the sky, but tonight was proof that photometric weather doesn't have to be good.  The wind picked up right after sunset and was gusting up to 25 or 30 mph.  Even now at sunrise, it's a sustained 15 mph.  Seeing wasn't horrible at the start of the night, but rapidly got bad.  At around 3 am I did a 1s I exposure pointed at the zenith, and measured the seeing at about 1.8 arcsec.  For interesting targets at airmasses greater than 1, the seeing was almost always over 2 arcseconds.  Let me tell you, that makes it very hard to do crowded-field photometry.

Three more nights to go, so it won't be a problem unless this wind keeps up.  Of course, not all is lost since I've developed my own set of seeing related terms in reference to the guide camera such as  edge crawl  fast changes in the psf which change the shape of individual stars,  field jump  the entire field moving back and forth, and  field swim  where it looks like everything is underwater and relative distances between stars seem to change.

Bob stayed up here to work on the tracking problem.  Instead of tracking correctly, the telescope starts to move in RA with a slide, jump-slide pattern.  Bob made an adjustment around 10:30 which seemed to fix things, but the problem came back right before I started doing morning twilight flats. 

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Submitted on 2004 Sep 14 [6:25:08]