From: Jon Brinkmann
Date: Mon, 15 Dec 2003 10:15:55 -0700
Subject: Re: 2.5m obslog 20031214 (MJD 52988)
>                        APACHE POINT OBSERVATORY SDSS 2.5M
>
>                                  OBSERVING LOG
>                             Sunday December 14, 2003
>
>                                   (MJD 52988)
...
> While checking-out the 2.5-Meter, I noticed a low-freq vibration when
> the az axis came to the end of its slew.
This is probably the occassional vibration we've noted for years in the
windbaffle servo (with both LVDTs and magnetorestrictive sensors).
We'll check to be sure.
Tuning it is very tricky.  If we dampen it to elimate the occassional
oscillation, it can't keep up with the telescope.  Since the
oscillations have never been a problem, we live with them.
Jon