From: Karen Kinemuchi
Subject: Re: [sloan-25mlog 5676] 2.5m obslog 20211006 (SJD 59494)
Date: Thu, 7 Oct 2021 06:57:32 -0600
> On Oct 7, 2021, at 6:08 AM, doravetz@apo.nmsu.edu wrote:
>=20
>=20
>                       APACHE POINT OBSERVATORY SDSS 2.5M
>=20
>                                 OBSERVING LOG
>                          Wednesday October 06, 2021
>=20
>                                  (SJD 59494)
>=20
> ----  Observing Team ----
>=20
> Karen Kinemuchi
> Dan Oravetz (R)
> Jos=C3=A9 S=C3=A1nchez-Gallego (BOSS testing)
> Kaike Pan (afternoon BOSS support)
> Tracy Naugle
>=20
> ---- Observing Plan ----
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> Focus sweep vs. altitude test.
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> ---- Observing Summary ----
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> The rotator got stuck in an out-of-closed-loop state at ROT=3D179:20:20 =
after the focus-vs-altitude dataset. The amplifier looked fine (all the =
status LEDs were reportedly good) and a cursory visual inspection of the =
rollers didn't turn-up anything obvious. We tried to issue moves in both =
the positive and negative directions from this location -- back in =
August when we experienced this problem, specifying /RotWrap=3Dnegative =
helped get out of this stuck position -- but the direction didn't fix =
the problem. After dozens of attempts at negative moves the rotator =
moved a total of about half a degree in the negative direction, but was =
still going out of closed loop immediately after sending a move command. =
Given the degraded seeing conditions and the hour, we closed with the =
rotator at 179 deg. We called Kaike and Tracy and then attached the fill =
extension so the 180L dewar would reach sp1 with the rotator at 179 deg. =
The TPM won't show the 180L pressure in this configuration, but th
> e fills=20
> will still work and Tracy is on his way to site anyhow.
Just a quick clarification: we ended up moving the 180 dewar over to the =
left (north) side of the podium instead of using the LN2 line extender.  =
We disconnected the transparent tubing from the floor, wheeled the dewar =
over, and connected the regular LN2 line without any problems.  We =
capped the tubing on the dewar side and was able to get a force fill =
going this morning (just in case).  The connector bolts/parts are =
sitting in the podium.