Subject: Re: [sloan-25mlog 6034] 2.5m obslog 20220425 (SJD 59695)
From: Kaike
Date: Tue, 26 Apr 2022 10:26:24 -0600
Thank you, Ryan, Karen, and Katie.=20
I added one section: Emergency,  in Observers document wiki page, link =
this document, along with other two.
-Kaike
>=20
>=20
> ---- Engineering Issues ----
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> * 2.5m Weather status information lost again at 03:30Z.  Restarting =
the
> optidew did not bring it back.  Information came back at 10:00Z.  Lost =
again
> at 10:30Z.
>=20
> * Enclosure will not move west for closing at 4:45Z.  See log for more =
details.
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> * Important link: =
http://www.apo.nmsu.edu/Telescopes/SDSS/emergclose.htm
>  To manually pull the enclosure closed.  See Problems in Detail for =
the
> troubleshooting steps, solution, and resolution of this difficulty.  A =
big
> thanks to Ryan on leading and solving this problem with emergency =
closure!
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> * Dust counts: 32,000.  We have reached our limit at 9:30Z and remain =
closed
> after we got the enclosure moving.
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> ---- Problems in Detail ----
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> At 4:45Z, we decided to close up since the wind gusts and dust counts =
were=20
> rising.  Seeing was at 3.5-5.0". =20
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> We discovered the west enclosure pendant was not functioning and the =
warning=20
> bell was not ringing to signify closure.  We checked all interlocks, =
and they
> were fine and live.  Nothing was obstructing the telescope at 5 =
degrees.
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> We called Ryan, who instructed us to try the bypass.  The enclosure =
bypass did
> not work.
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> We swapped out a relay and that did not work.  We did discover that if =
the
> west door pendant was set to "F" or "Fast", we could hear the relay =
switch
> click in the rolling enclosure box.
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> We checked the breakers on the south wall panel, and they were not =
tripped.
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> Ryan then decided to come to site.
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> When we returned to the control room to wait for Ryan, we noticed that =
STUI
> was reporting the telescope was at stow position and tracking, when in=20=
> fact we left it at 5 degrees.  We issued a tcc axis stop to end =
tracking, then
> in a few moments, STUI status window reported telescope at 5 degrees.  =
MCP Menu
> correctly identified the position of the telescope which was at 5 =
degrees.
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> Ryan arrived on site and proceeded to systematically go through each =
component
> of the west door pendant, the rolling enclosure box, the breakers, and =
west
> door pendant winch housing.  We tried calling James and Tracy to get =
more
> suggestions, but could not reach them at 1am local.
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> We decided we needed to manually close the enclosure and turned on the =
red=20
> winches in the west corners of the enclosure.  We attached ratchets to =
the hooks
> and connected the ratchets to the rings along the west railing of the =
apron.
> When we turned on the winch motors, we could not move the enclosure =
because
> the motor brakes were engaged.  We tried to find a way to release the =
brakes,
> but were unsuccessful.  Ryan swapped the east door pendant with the =
west
> door pendant to see if that would work, but it did not.
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> During a break to warm up, we did an internet/wiki search for more =
information
> on how to manually close the enclosure.  During this time, we hit our =
dust
> limit of 30,000 counts at this high humidity. =20
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> We found an archived link from SDSS-I (you read that right, SDSS ONE =
in the
> year 2000), and used those emergency shutdown instructions.  This is =
what we
> did:
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> There are 4 large thumb screws above each blue enclosure motors.  =
These thumb
> screws are screwed in to the enclosure itself.  Screwing them out, you =
can
> insert them in an oval port in each motor.  This releases the brake.=20=
> The hardest motor to get to is under the SDSS Turtle cart cabinet.
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> Once the thumb screws are in place, the building will lurch and move a =
little
> bit, so watch your toes.  Ryan, Katie, and Karen physically ratcheted =
and=20
> moved the enclosure a few feet closed to get winch lines taut and =
ready. =20
> Then we turned on (push the buttons on the controls - either "forward" =
or
> "reverse" depending if you are on the north or south side) the red =
winch=20
> motors on the west corners of the enclosure.  To aid in the enclosure =
movement,
> we all pushed on the building as we guided it home.
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> Once the building was in place, we placed in the enclosure pins, =
closed the=20
> enclosure doors, and moved telescope to stow.  We returned the big =
thumb
> screws back into their locations above the blue motors in the =
enclosure walls.
> Enclosure building brakes are re-engaged.
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> Ryan knows that the optics will need to be cleaned again since the =
telescope
> was outside during the high dust levels and humidity. The day crew =
will look
> into the enclosure pendants and the wiring in the rolling enclosure =
box to
> identify the problem in the morning.  Stay tuned to the day log for =
the coming
> day.  We will document the whole procedure for posterity, but hope =
this will
> never happen again.
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> For reference, here is the link we found that described the process =
and=20
> contained the missing information we required for this difficult task.
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> http://www.apo.nmsu.edu/Telescopes/SDSS/emergclose.htm
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>=20
> ____________________________________________________________
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> =
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