MDM Trouble Report for 2007 Dec 15

Telescope: 2.4m
Observer(s): Yee & Eastman (OSU)
Instrument: CCDS+Retrocam

Problem(s) Encountered:
    At 11:24 PM, after tracking successfully for ~7 minutes at 03:32:25.0 -0:38.07, at HA = +01:00 (+/- 1 minute), dome azimuth 207 (+/- 5) degrees, the dome started moving until it eclipsed the telescope and we lost our guide star. The dome moved at least 30 degrees during this time, then moved back to the correct position on its own.

    At 11:53 PM, HA=+1:28, same position on sky, when the dome error reached -3 (ish) degrees, the dome overshot its correction and moved from ~215 to ~255 (an error of 36.1 degrees). Again, we lost our guide star as the dome eclipsed the telescope, but after it got to 255 degrees, it moved back to the correct position on its own.

    We started monitoring every dome correction after the second failure. These were the results.

    ~-3 to 36.1 to ~0
    -3.3 to 0.0
    -2.9 to 1.0 to 0.0
    -3.1 to 6.7 to 0.2
    ~-2 to 0.1

-2.2 to 0.1
~-3 to -0.4
-2.8 to 0
~-2.4 to -0.1
-2.4 0.0
-2.7 to -0.1
-2.4 to -0.1
5.1 to -1.6 to 1.0 to 0.0
4.3 to -1.8 to 1.1 to 0.0
5.3 to 0.1
>4.4 to 0.1
>4.7 to 0.1
<-5.1 to 1.7 to -1.3 to -0.1
-5.9 to 1.6 to -0.2
<-4.4 to 6.1 to -2.0 to 0.6 to -0.3
14 to 1.4 to -0.1
-5.6 to 2.0 to -0.5
-6.3 to 1.8 to 1.1 to 0.1
-6.5 to -7.3 to -1.4 to -0.2
<-3.1 to -0.2
-3.4 to 0.0

Several times the dome error exceeded 10 degress. Usually, we changed targets shortly afterwards, so the dome never got the opportunity to correct itself. The dome error got as high as 15.6 degrees at one point.

    Additionally, the guider speaker is broken; instead of beeping as it should when the guide star is lost, it softly clicks.

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

Submitted on 2007 Dec 15 [7:12:09]