Date: Fri, 26 Dec 2003 08:44:40 -0700 (MST)
From: Peregrine McGehee
Subject: Re: 2.5m obslog 20031225 (MJD 52999)
Re: Plate 1638
From the focus information recorded in the observing log it appears
that the seeing FWHM was at least marginally larger during this plate.
From our experience last year I rechecked the plPlugMap files to find that
"reddeningMed" was indeed set correctly to 0.
Is there any QA information available such as differences in the
guiding signal from separate guide fibers that would point to problems
in hole positions?
The 11 arcsec offsets were just at the minimum for the conditions
listed. The formula listed in the observing procedures assumes the
tracking errors are double what was discussed in the engineering
circles:
    offset = 2.24*FWHM + 1.5 + 2*0.1*exptime_minutes
shows the explicit exposure time dependence.
- Peregrine
--
Peregrine M. McGehee	http://astro.nmsu.edu/~peregrin
Department of Astronomy
New Mexico State University, Las Cruces, New Mexico