From: stephanie snedden
Subject: Re: 2.5m obslog 20080116 (MJD 54482)
Date: Thu, 17 Jan 2008 11:30:03 -0700
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This is the same problem that we had recently (in the last month,
anyway), where if the spectro focus is set for a cold temperature,
the collimator actuators reach a limit during the dithered flat tilt
moves and fail to complete the move. This was a topic in the last ops
phone con, and the solution is to set the spectrograph red camera
lenses to a "winter position" so the typical winter focus is not so
near the actuator limit. We have no written procedure for this,
although I hope to have a draft ready for testing this shakeup/down.
For tonight and tomorrow night, if the focus is set for -2C or colder
and the temps are really that cold, don't bother trying dithered flats.
Steph
On Jan 17, 2008, at 4:44 AM, Audrey Simmons wrote:
>
>
> We attmepted to gather dithered flats several different times, but
> an error
> repeatedly came back saying that the mechanicals did not respond
> correctly.
> Maybe the motors had trouble because of the cold temperatures?
>
> 08:50Z - Took dithered flats, starting with exposure 49049 and
> ending at
> 49058. After the tenth flat, and error message came back:
>
> "Finished with specFlat 10 of 15.
> Setting up Collimator
> 2008-01-17 09:30:41Z: Original command was !mb100!
> 2008-01-17 09:30:41Z: expected reply was !mb100
> OK!
> motor b: Mechanicals did not respond correctly; response was mb100
>
> invalid keyed list format: list contains an empty field entry
> Error: problem with motors (see previous error message)
> Original motor positions: {a -15424} {b -16010} {c -16610}
> Current motor positions: {a -15313} {b -15898} {c -16610}"
>
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This is the same problem that we had recently (in the last month, =
anyway), where if the spectro focus is set for a cold temperature, the =
collimator actuators reach a limit during the dithered flat tilt moves =
and fail to complete the move. This was a topic in the last ops phone =
con, and the solution is to set the spectrograph red camera lenses to a =
"winter position" so the typical winter focus is not so near the =
actuator limit. We have no written procedure for this, although I hope =
to have a draft ready for testing this shakeup/down. For tonight and =
tomorrow night, if the focus is set for -2C or colder and the temps are =
really that cold, don't bother trying dithered flats.StephOn Jan 17, 2008, at =
4:44 AM, Audrey Simmons wrote:We =
attmepted to gather dithered flats several different times, but an =
error=A0repeatedly came back saying that the mechanicals did =
not respond correctly.=A0Maybe =
the motors had trouble because of the cold temperatures?08:50Z - Took dithered flats, =
starting with exposure 49049 and ending at=A049058. =
After the tenth flat, and error message came back:"Finished with specFlat 10 of 15.Setting up =
Collimator2008-01-17 09:30:41Z: Original =
command was !mb100!2008-01-17 09:30:41Z: =
expected reply was !mb100OK!motor b: Mechanicals did not respond correctly; =
response was mb100invalid keyed list format: list =
contains an empty field entryError: =
problem with motors (see previous error message)Original motor positions: {a -15424} {b -16010} {c =
-16610}Current motor positions: {a =
-15313} {b -15898} {c -16610}"=
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