UNSWIRF: hardware setup

The hardware components of UNSWIRF

UNSWIRF consists of the following pieces of hardware:

Setting up the hardware

Some of the setup is done by the AAO staff, and some is done by the user before observing.

AAO staff tasks

Prior to the observer arriving, the AAO staff will have set up the instrument as follows:

Observer tasks

  1. The following items need to be located (they are usually in the Plate Room on the 6th floor, but may be in the 4th floor instrument room):
  2. Ensure that the Hatfield polarimeter slides are out of the way. This means that the two screw threads with attached butterfly nuts must be fully out. This is necessary even if the polarimeter modules are not in place. You may need to remove cables connected to the modules.
  3. Install the Fabry-Perot in the slide:
  4. Install the slide in the UNSWIRF box:
  5. Boot the PC computer:
  6. Cabling the F-P and slide:
  7. Verifying the slide operation:
  8. Setting up the CS-100 controller: If the above sequence fails, you will need to read the CS-100 manual for further advice.
  9. Remove the perspex cover from the top of the Fabry-Perot, taking great care not to drop the screws onto the etalon.

    Setting the parallelism

    The F-P and its controller appear to be stable enough that the plate parallelism can be dialed-up and forgotten about as long as the temperature and humidity do not change dramatically. Nevertheless, it is good practice to check the parallelism, since if wrong it will make your data very hard to analyse. The parallelism can be checked most easily during the daytime using an argon comparison lamp.

    1. Recheck the resistive balance of the CS-100.
    2. Place an A4 sheet of white paper above the F-P on the aluminium mounting flange to cover the 200mm hole (use sticky tape to hold the paper in place). The purpose of the paper is to act as a diffuse reflector for the comparison lamp.
    3. Place an argon comparison lamp in the UNSWIRF box. The lamp itself should rest on the black aluminium cover into which the F-P retracts when moved out of the beam. Use some sticky tape to stop the lamp from moving around (and possibly falling onto the F-P).
    4. Plug the lamp power supply into one socket of the mains outlet that is controllable from the console (ensure that the UNSWIRF rack is not plugged into this socket).
    5. Turn off the lights (incandescents and fluoros) in the cass cage. It is not necessary to turn off the dome lights.
    6. On the IRIS VAX terminal select METHOD 1, CYCLES 2, PERIOD 1, TIME 1.5, IME 1, ITIME 1.5, LF open, UF 1.65. These parameters are suitable for the 1.6519 micron argon line.
    7. On UNSWIRF do ``x -490 y 499 z -30''. If necessary, put the F-P in the beam with the command ``slide in slide 150''.
    8. With the lamp off, take an exposure and use it as a dark (i.e., ``use nnn dark'').
    9. Turn the lamp on. You should see an obvious increase in flux, hopefully in a circularly symmetric pattern.
    10. Now tweak the ``z'' setting (using commands such as ``dz 5'' or ``dz -5'') and note the affect on the display. As you go to more negative z, you should see a donut of light steadily moving out towards the edges of the plates. Make a note of the ``z'' setting at which the donut is at the periphery (or 90% of the way there).
    11. Use the Perl script cube.pl to set up a run file (use ``./cube.pl > /vaxdata/obsred/unswirf/yourfilename.dat'') of 16 or so images at delta-z of 2 about the line centre, and execute this file using ``unsw yourfilename.dat''.
    12. Convert the data to FITS format by running docube on the output files, then read the FITS cube into IRAF with rfits.
    13. Run the unswslope.cl script.
    14. Take the dX and dY values output by unswslope.cl, and append them to the lines $xx=... and $yy=... in BOTH arc.pl and cube.pl.
    15. Repeat the comparison lamp cube, rerun ``unswslope'', and iterate the correction if necessary. The absolute values of the X and Y slopes should both be less than about 0.01 (corresponding to a precision in the X and Y settings of about 2).

    Problems that have occurred with UNSWIRF in the past:

    Existing problems:

    Planned enhancements:

    Last updated 19-Apr-1997

    UNSWIRF: hardware / Michael Ashley / mcba@newt.phys.unsw.edu.au