WORKING WITH AUXPORT and AG2 camera
Auxport imaging facilities at WHT.
TEK2 is the CCD offered, 0.11 arcsec per pixel, UBVRI filters.
Telescope focus 97.92 in R, or about 0.1mm higher than ISIS (5/8/07)
Using instrument AUX will report a rotator position 90
degrees offset with respect to ISIS. However, GSS
does NOT take this into account even when
specifying AUX as station. Therefore, for guiding there are two options:
If using INSTRUMENT ISIS while observing with AUX, it generally best to
use an angle of 45 degrees (or -45, 135, 225, etc) in order to align the CCD
with the cardinal directions.
With Rot Sky 0, INSTR ISIS, the orientations with TEK2 will be:
- Use ISIS setup and forget the rest.
- Use AUX setup but subtract 90 degrees from sky PA
when searching guidestars. (Add 90,000 to theta output).
North | AUX |
| TEK2 |
| Gen 3 |
Working with AG2
AG2 is a fast-readout frame-transfer science CCD, that works the same way as
an autoguider, Gen III udas, to allow ultra-fast photometry.
It has a number
of operating peculiarities that need to be recorded:
Observing out of focus to prevent saturation of bright stars, even with <10s
exposures. Typically Telescope Focus 99.0mm.
This requires Autoguider focus to be adjusted near its limit: 6500 for the
above telescope focus (17-Sep-2007)
They require very precise and reproducible positioning on the detector.
This means recording Autoguider Probe positions and pixel x,y for each
Since they follow an object for many hours, you have to make sure it will not
be interrupted by rotator limits. Wind off rotator if necessary.
Watch out for dome stopping tracking if object is in the south.