Subject: Re: [sloan-25mlog 2863] 2.5m obslog 20160304 (SJD 57452)
From: Karen Kinemuchi
Date: Sat, 5 Mar 2016 15:50:20 -0700
Hi Dan,
	Yes, I remember this quick J/K test to check the counterweight =
balance.  I can run that this afternoon during checkout  (it's cloudy =
now with radar in the county) and can report the values I find in the =
night log.  If we find the numbers to be grossly out, we can reset the =
counterweight values to the ones posted on the White Board of Powerful =
Info in the control room.
	Thanks!
	Karen and Audrey
On Mar 5, 2016, at 8:15 AM, Dan Long wrote:
> Hi Karen and Audrey,
>=20
>   That is definitely an indication that the altitude is out of balance =
and top heavy.  There is a test that once upon a time was part of =
afternoon checkout, where one used the mcp j and k incremental velocity =
keys to look at the motor voltages going up and down slowly (5000 =
cts/sec or so). =20
>=20
>   One should see a fairly symmetric reading of about 1000 units going =
up and -1000 units going down when monitoring over several seconds as =
seen in the mcpMenu.  My guess is the counterweights are around 20-30 =
ticks too high (the dewars between full and empty will change the =
balance on the order of 10-15 ticks).
>=20
> 		Cheers,
>=20
> 		   Dan
>=20
>=20
>> On Mar 5, 2016, at 6:01 AM, kinemuchi@apo.nmsu.edu wrote:
>>=20
>>=20
>>                      APACHE POINT OBSERVATORY SDSS 2.5M
>>=20
>>                                OBSERVING LOG
>>                         Friday March 04, 2016
>>=20
>>                                 (SJD 57452)
>>=20
>> ----  Observing Team ----
>>=20
>> Audrey Oravetz
>> Karen Kinemuchi
>>=20
>> kaike Pan (afternoon)
>>=20
>>=20
> .
> .
> .
>=20
>> When the telescope is slow to the stow position, 121, 30. It stopped =
at
>> 121, 30. But as soon as "axis stop" and a stop was engaged, it went =
dow
>> 0.5 degree to 29.5. When LN2 was connected, it started filling. It =
was a little
>> top-heavy.=20
>>=20
>> APO evening calibration was taken, checked.
>>=20
>> 00:15Z started ventilation.
>>=20
>> NIGHT:
>> =3D=3D=3D=3D=3D=3D
>> 01:08:55  encl25m : open; =20
>>=20
>> We noticed that after the telescope did the primary fill and moving =
from 5
>> degree to stow, after the issuing of tcc axis stop and stop button, =
the
>> telescope still slipped by 0.5 degree in altitude (30 degrees -> =
29.5).  We
>> think it may not be related to the dewars being empty or not.  We =
will continue
>> to monitor the telescope and see if more altitude slips happen around =
stow position.
>>=20
>=20
> .
> .
> .
>> ---- Telescope Status ----
>>=20
>> 00:15Z     Started ventilation
>> 01:08Z     encl25m : open
>> 12:44Z     encl25m : closed
>>=20
>> No interlocks bypassed
>>=20
>> Status at:   12:55:38=20
>> Telescope stowed at:    121.0, 29.6,   0.0  mount
>> Instrument mounted:     cartridge =3D 3
>> Counterweights at:      454, 455, 455, 455=20
>> LN2 autofill systems:   Connected and turned on
>> 180L LN2 dewar scales:  SP1    209.8 lbs, 16.2 psi
>>                       SP2    232.0 lbs, 20.2 psi
>=20