Date: Sat, 23 Oct 2004 11:27:01 -0600
From: Dan Long
Subject: Re: 2.5m obslog 20041022 (MJD 53301)
>                        APACHE POINT OBSERVATORY SDSS 2.5M
>
>                                  OBSERVING LOG
>                             Friday October 22, 2004
>
>                                   (MJD 53301)
>
>---=== OBSERVING TEAM ===---
>
>Swing:          Pete Newman
>Night:          Steph Snedden, Atsuko Nitta
>Support:        Craig Loomis
>Visitors:       Fritz de Jongh (SNe Team, FNAL)
>
>
>---=== OBSERVING PLAN ===---
>
>Shake-up testing then science.
>
>---=== OBSERVING SUMMARY ===---
>
>
>o Finished plate 1557. Signals on 1865. We spent about 1.5hrs trying to get
>   sp2 back in spec before observing 1865 during the second half of the night.
>
An added note here.  I went back and looked at SoS data from the two
other nights when positional or wavelength shifts were seen in sp2
(53289, 53297), and in both cases the problem showed up in both
cameras, so something was/is moving in the light path prior to the
dichroic.  In the earlier situations, the corrective movements of the
collimator seemed reasonable.  The ones from last night clearly
weren't, so it seems that something is getting looser, and is quite
likely in the collimator actuator system.
>
>02:30Z The second exposure is also bad. Since there is no other plates
>        with reasonably Zappa numbers that we can do until cart 6 plate
Shouldn't that be Child-of-Zappa numbers? :)
				Cheers,
				  Dan