Adjuster Tests May - August 2002

Joint Astronomy Centre

JAC Home
JCMT
UKIRT
Contact info
JAC Divisions
OMP
Outreach
Seminars
Staff-only Wiki
Weather
Web Cameras

____________________


JCMT home

Telescope
Surface

RxH3 maps
RxH3 History
RxH2 Maps

Some Beam Maps
Ruze Efficiencies
RxH3 Receiver
OOF Maps
ASCS (old)
Movies (old)

Adjuster Tests May - August 2002

On 12 May 2002 we made a hardware test of the sectors 1 to 6, by moving up (by 33 steps/ 100 micron) in six panels
(one in each sectors) all three motors that are known (thought) to be good.
80 GHz RxH3 maps were made after the moves and after moving the panels back. The figure below shows the difference
of both maps (eliminating large scale errors and stuck panels).
The motors seemed to have moved indeed with the expected amount (a positive move results in a negative phase offset).
The blue dashed lines drawn on the telescope separate the different sectors.
The location of the panels was obtained from a drawing of the dish, assuming that the diameter is exactly 15 meters,
and that the observed dish is centered at (0,0); however this drawing does not seem to be very accurate.

Tests of flagged motors

On 27 May, 2 June, and 15 June 2002 we have investigated motors which had in their status a wheel error, but no wheel reference
and no phase error. Of these motors it was not known whether they are moving or not
(these are the blue motors in the figure below; the red ones do not move or move erratically).

We moved these motors (and other motors in the same panel, unless they were flagged) up (in one case down) by 33 steps (100 micron),
and back again, in groups of up to 12 panels. After each move an 80 GHz RxH3 map was made.
First results are shown in the figures below (again as difference maps).
The drawing below each map shows the motors that we tried to move (those with a wheel error as red dots).
A comparison of the figures shows that most of the motors with wheel errors did move, but there are motors
which did not move (even among the panels that are thought to be ok).
The third map shows stripes (probably originating in the reduction program for unknown reasons -
this is being investigated). Most of the motors in this map are retested in maps 5 to 7 (maps 6 and 7 will be obtained soon).
Upon completion of the tests we shall have an overview of which adjusters need repair and make a list of priorities,
based on location, error in panel position and other criteria.