MDM Observatory 1.3m Telescope Observing Report for 2011 Jul 08

Observer(s): Gaidos 
Institution(s): University of Hawaii

Instrument: Mark III

Worked for 7 hours (most of the night)
Conditions were Mixed most of the night.
Problems were encountered, see the separate trouble report for details.

Seeing and Weather:
   Clouds from 0400 until sunri.
   Beg: Seeing 2 arcsec, Patchy Clouds, Winds Calm
   Mid: Seeing 1.5 arcsec, Clear, Winds Light & Variable
   End: Seeing 1.5 arcsec, Overcast, Winds Moderate

Observing Summary:

Preamble:  an apology for not submitting observing reports for the three previous nights. I am still becoming acquainted with the system.

Weather: Last night (local July 8) was a significant improvement over
the previous three nights which had the usual monsoonal conditions.
Instead, it was drier and prevailing flow was from the
south-southwest, which kept the major storms to the east, with one
notable exception: around 3 AM an isolated storm with intense
cloud-to-ground lightning moved north to the west of Kitt Peak,
crossing over Sells.  Higher clouds associated with this cell obscured
the target, and along with twilight, forced shutdown around 0430.  The
night started with broken clouds that dissipated after 2100.  Wind was
light to moderate with variable direction.

Seeing: The slit image suggested poor (>1.5 ) seeing early in the
night to the northeast.  This seemed to improve with time, although
part of this was probably meridional transit of the target.

Technical issues:  

The largest issue is the previously documented  jitter  in
declination.  This problem was rampant during the first half of the
night, but then almost completely went away.  Importantly, there was
little or light wind the first part of the night, and the telescope
was oriented away from the wind, so I am not convinced that it is just
wind-triggered.  Many times, the telescope seemed to cycle through
multiple, specific positions in declination, with almost periodic
regularity.  A complete cycle would take about a minute.  Fortunately
this direction is along the direction of the slit, but nevertheless,
this reduces the effetive SNR of the spectrum and to compensate I
doubled my total exposure times.  Another important observation: this
jitter did not occur, or at least was not siginficant, during
observations on the previous 3 nights (albeit those periods were
brief).  The amplitude of the jitter was about 10-20 arc-seconds.

I also noticed that the response of the telescope to declination move
commands (either by the real or virtual paddle) was poorer on this
night compared to previous nights.  The telescope seemed to be
 sticky , i.e., multiple commands would be ignored, then the telescope
would suddenly move a comparatively large distance in declination.
Its performance in RA was much smoother.

The other issue, also previously documented, was the tendency for the
telescope to suddenly stop tracking after completing a slew.  Note: on
at least one occasion there was no dome motion involved.  Sometimes,
mutliple refresh and slew commands were required to get to a target.
In many instances, the telescope would successfuully move to the
target, track it for a couple of seconds, and then declare an error
about calculating slew and tracking would stop.  In other cases, the
telescope would never start the slew, declare an error, and stop
tracking.

Every time I tried the  RA and Dec  (telescope) home commands, I got
error messages and the telescope stopped slewing and accepting
commands.  I had to issue stop and start telescope commands and
restart and reinitialize the gui to get it to work again.  The dome
home command works, though.


The Fandub-ian warning  Mirror mirror neither open nor closed 
did not appear as it did the previous night.

Commercial power dropped out around 0300 and the generator kicked in.
As of the afternoon of July 9 the power was still out but the
generator and UPS at the 1.3m appear to be working normally.

On the positive side, I am impressed how well the telescope tracks.
For many exposures <5 minutes, no guiding was needed to keep the
target on the slit.  Also, absolute pointing accuracy in RA was
impressive.  Slews of many degrees would place the target directly on
the slit!

The dome seems water-tight.  After a horrendous rainstorm (3  total)
with heavy wind, I noticed no leaks.

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

Submitted on 2011 Jul 9 [16:05:28]
NOTE: This report replaces the previous 1.3m telescope
      observing report for 2011 Jul 08