MDM Observatory 1.3m Telescope Observer's Report for 2005 Nov 02

Observer(s): Martin Bureau , Anne-Marie Weijmans
Institution(s): Oxford University, Leiden Univ.

Instrument: Direct Imaging, f/7.6, echelle

Worked for 09:30 hours (all night)
Conditions were Non-Photometric most of the night.
Problems were encountered, see the separate trouble report for details.

Seeing and Weather:
   Beg: Seeing 1.3 arcsec, Cirrus, Winds Calm
   Mid: Seeing 1.5 arcsec, Cirrus, Winds Calm
   End: Seeing 1.7 arcsec, Cirrus, Winds Calm

Observing Summary:

Continuation of an optical imaging follow-up of the Sauron survey of
early-type galaxies. The sky was partially clear with scattered cirrus
for the first half of the night, with seeing around 1.3 . The second
half was worse, with more and thicker clouds, and seeing around 1.7 .
All of the night was thus usable but we had too substantially lengthen
our exposure (from 50 to 100% longer than planned). We also lost the
guiding star a few times... Since this is the first night with this
set-up, the focus was also way off, so it took a bit longer than usual
to focus at the beginning of the night. Similarly, the pointing was really
bad to start with, so much so that it was impossible to find a bright star
even by scanning around the target position extensively. In the end, we had
to use the tilt meters to calibrate the pointing. This went quick but we did
loose about 90 minutes for the whole process.

We also repeatedly had problems with the bias level of the CCD. Many
exposures had a substantial number of bad rows, so much so that many
exposures were useless. Although we have no proof of this, it seems
that doing a  df  helps to solve the problem. More details in the
fault report.

------------------------------

Submitted on 2005 Nov 3 [7:27:11]