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Engineering
WORKING WITH SCAM
SCAM uses the 'new' UV derotator on GHRIL side. TCS version W23-1-4 and higher
allow for this configuration. The new UV derotator has an unvignetted field of
30" diameter and 3.5' full FOV with 1.5 mag. vignetting at the edge. The
vignetting 1.2' away from the centre is 0.7 mag.
Startup
TCS:
- USER> STATION GHRIL_UVDEROT
- USER> INSTRUMENT SCAM
- USER> AGSELECT STJ
- Zeroset AZ and ALT
to zeroset on the targets switch to computer control:
- USER> AZ 298
- USER> ALT 89
- USER> ENG
- USER> ZERO AZ TAR
- USER> ZERO ALT TAR
Drive AZ and ALT slowly in + direction over the zeroset target points,
then switch to computer control again
to zeroset absolute:
- USER> ZERO AZ ABS
- USER> ZERO ALT ABS
Zeroset absolute will go wrong in case an absolute encoder bulb is broken!
When slewing to the first object check azimuth and altitude incremental and
absolute encoders are in close agreement and updating.
- USER> ZERO ROT ABS
- USER> WAVELENGTH ...
- USER> TEMP ...
- USER> PRESS ...
- USER> HUMI ...
- USER> UT1UTC ...
- USER> CAL LAST
- USER> FOCUS 103.76
Autoguiding:
The light for the autoguider is reflected off a 45 degree flat mirror with a
50" hole in the middle to allow for light to reach the STJ camera.
Preparation
Rotator centre, 7 star calibrate and aperture offset: first night
only.
To acquire a guide star use a big window.
SYS> window AG2 1 "[21:1000,1:977]" was used covering the detector array
located at the pixel 909,846.
Once you have a guide star re-define the window to a box of e.g. 200x200
to speed up the guide loop.
Observing
SCAM does not use ICL or the observing system on taurus.
Acquisition is done on the top right corner of AG2 by putting
a mirror in the beam.
To observe, the mirror is moved to allow light go through a hole in it
to S-CAM. Autoguiding is possible only when a bright enough star is visible
in the rest of the AG2 field.
I've defined a "region file" which you can load onto SAOimage as stj.reg.
The circle is the rotator centre with no aperture offset and the "plus" marks
the centre pixel of S-CAM (approx).
Use AP 0 2.4 4.6 to make this point also the centre of rotation.
Leave telescope at AZ=222 in the morning, position to point GHRIL to AP3 floor
for access for Helium fill (they do).
XY HANDSET cursor keys, the arrows show how the object moves
on the detector:
PA=0: +------+
| N|
| ^ |
| / |
| / |
+------+------+------+
| \ | / |W |
| \ | / | ^ |
| v | v | \ |
| E|S | \ |
+------+------+------+
Data Handling
Done by observers on their own data acquisition system.