Working with AUX

WORKING WITH AUXPORT and AG2 camera

revised 05/08/07

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:

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).

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:



        East
      ----------
      |        |
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 target.

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.