Date: Thu, 22 Mar 2001 17:34:43 -0800
From: Russell E Owen
Subject: Re: SDSS 2.5m NightLog 21Mar01 51990
>Russell called just after we switched cartridges. He asked for some more
>details.  We were trying to track this up until about 22:40.
>stripeAxisRates said we should see a rotator tracking rate of about a few
>"/s; we were seeing something more like 1'(!)/s.  We issued the gotoField
>for this plate at 20:09:41 (thank you, SOPGUI, for that information.) We
>continued futzing back and forth between the field and an fk5 star until
>22:32:53.  (For more information, you can grep for SOPGUI in the murmur
>log, although we only used it for the first half of our futzing.)
You can get the TCC to tell you what velocity it is requesting by
doing: SHOW MOUNT. If this problem comes up again, please do that.
RotMount gives you requested position, velocity and time. TelMount
gives you similar information for az and alt. (Note: AXIS STATUS does
not give correct velocity; PR 2130 was filed about a week ago about
this.)
Looking through the log of data sent by the MCP to the TCC, the slew
to the plate ended at around 03:10:33 UT (subtract 7 hours to get
local time). Shortly after that the rotator velocity was 0.007
deg/sec = 25"/sec. Hence I am somewhat suspicious of your rotation
rate calculations. (Can stripeAxisRates calculate rotation rates for
spectroscopy? From the name, it sounds as if it's intended for drift
scanning, which will have very different rates.)
-- Russell
P.S.
Here's the extract from the MCP -> TCC log. The time tag is funny,
but it's the right time.
985230626.18 AZ  MOVE 151.8309351 0.0035023 11467.02900
985230626.18   OK
985230626.28 ALT MOVE 61.7020144 0.0016531 11467.02900
985230626.29   OK
985230626.45 ROT MOVE -45.0119864 0.0065444 11467.02900
Here's some data from around then from the TCC. This shows a rate of
approx. 0.006 deg/sec, so it all seems to hang together.
2001-03-22.03:10:23.483 0 0 I TCCStatus="TTT","NNN";
TCCPos=151.79,61.68,-45.09; AxePos=151.79,61.68,-45.09
2001-03-22.03:10:24.043 0 0 I TCCStatus="TTT","NNN";
TCCPos=151.79,61.68,-45.09; AxePos=151.79,61.68,-45.09
2001-03-22.03:10:33.963 0 0 I TCCStatus="TTT","NNN";
TCCPos=151.83,61.70,-45.02; AxePos=151.83,61.70,-45.02
2001-03-22.03:10:43.883 0 0 I TCCStatus="TTT","NNN";
TCCPos=151.86,61.72,-44.96; AxePos=151.86,61.72,-44.96