MDM Trouble Report for 2010 Jun 16

Telescope: 1.3m
Observer(s): Jules Halpern (Columbia U.)
Instrument: Templeton

Problem(s) Encountered:
I've been observing on the MDM 1.3m for three nights.  Here
are some more observations about the N-S guiding problem that
may provide additional clues:

In order to stop the telescope from oscillating, I have to
set the N-S guide rate in the guider to 5 or 6 pixels per second.
This is more than the default value of 2.

But when the telescope is not oscillating, it does not seem to be
able to guide at all in the N-S direction. The telescope will
slowly drift to the north, and the guider is unable to center it.
When the star finally reaches the the edge of the guide box,
the guider quits guiding and the tracking shuts off.  Why does
the tracking shut off? I've seen this behavior now four times.

Occasionally I see the N-S oscillation even when the guider
is turned off.  This implies that the telescope is trying
to make a guide motion on its own, as if it has programmed
in it a certain amount of tracking motion in the N-S direction.

The software hand paddle is not able to make small motions north
or south.  When I set the step to 10 arcseconds, it does nothing
no matter how many times I press N or S.  However, it is able to
make N or S motions of 60 arcseconds.  And it is able to make
any length motions E or W.

Almost nothing in the N-S guide function is right.
All of this behavior feels as though it could be explained if
there is a lot of backlash within the declination guide motor.

I've also sent this report to Richard Treffers.

-Jules-


------------------------------

Submitted on 2010 Jun 17 [2:15:17]