Subject: Re: [sdss3-25mlog 1095] 2.5m obslog 20130302 (MJD 56354)
From: Dan Long
Date: Sun, 3 Mar 2013 09:11:37 -0700
On Mar 3, 2013, at 6:06 AM, dmbiz@apo.nmsu.edu wrote:
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>                       APACHE POINT OBSERVATORY SDSS 2.5M
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>                                 OBSERVING LOG
>                          Saturday March 02, 2013
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>                                  (MJD 56354)
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> ----  Observing Team ----
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> Moses Marchante
> Dmitry Bizyaev
> Elena Malanushenko - swing
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> ---- Observing Plan ----
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> 2 Mar 2013  56354.0  0.62  02:09 12:21  05:50 16:03 =20
> BOSS until 06:22 (4.2 h), then APOGEE (6.3 h)
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> ---- Observing Summary ----
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> At 10:30 we got problems with unmounting cartridge 7.=20
> Lost 21 minutes due to this problem. See log for details.=20
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> When I tried to dismount cart 7 at ~10:30Z, there was a problem:
> lift did not move. I checked coordinates (they were 120:59:59, 90.00, =
0.00)
> switched handpaddle to the manual side and tried again.=20
> Lift moved, slit head latches came off, but the main latches not.=20
> Moved cart out-in, tried again.=20
> Noticed that ALT axis got foducial errors. Moved cart out, accepted
> fiducials, corrected and went to InstChange again. It did not help.=20
> Then I assumed that fiducial error at AZ axis that was huge (~484,000)
> is actually real. Corrected fiducial. Tried to mount=20
> cart again. It did not work again. Assumed rotator got hidden fiducial
> error. Moved cart out, Moved rotator. It was OK, no fiducial=20
> errors. Then tried to move telescope to 60,60,60, was
> ensured than there are no any fiducial problems. Went back to the =
InstChange
> position. Tried to mount cart 4 again, and that time it worked.=20
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> By some reason telecope got huge fiducial error to AZ axis, and small =
one to ALT
> axis, which complicated the fixing.=20
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> 10:51 - returned back to normal operations.=20
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> 21 minutes was lost due to this problem.=20
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   I see no mention of checking the interlocks display to see why the =
lift wouldn't move.  Please identify _why_ the lift won't move before =
bypassing interlocks by moving the lift pendant to the manual side.  =
Doing so saves debugging time and potential risk to the hardware. =20
   Looking at the interlock data from the tpm, at least initially the =
reason the lift wouldn't move up was because the azimuth was not at stow =
according to the position switches, which matches your eventual =
diagnosis of a fiducial error large enough not to actuate the azimuth =
stow switches.  This would have been shown in the interlocks display =
under instrumentChange-->lift_up_enable.
-Dan