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P60-506: Active Asteroids and Other Unusual Solar System Objects

P.I.: Jane Luu

This is a ToO program for non-sidereal targets. Can now (since Sep 2019) be triggered via the OB generator.

Spectroscopy setup:

  • Gr #3
  • Slit_1.0''
  • Blocking filter GG345 (#94) in FASU

Imaging setup:

  • B (#74), V (#75) and R (#76) filters

Daytime calibrations:

The standard twilight flats in BVR filters is sufficient.

Run alfosc.alfosc-calibs in the morning after observations. This provides biases for both modes with the window and/or binning used, as well as halogen flats and arc lamps for the spectroscopy mode used.

Remember to fill the tracking log of this program.

Observing instructions:

The OB comments will indicate the preferred order of the OBs whether standards should be taken before or after.
  1. Go to directory: cd ~/obs/scripts/60-506/
    Do ls -lrt to see the scripts and run them as indicated in the trigger.

  2. When the OB generator asks you to do the pointing and differential tracking in another sequencer window , you can get the target position and RA/DEC rates for the current UT in either of these ways:

    • Use tcs.asteph "NAME" which will look-up JPL Horizons to get position and RA/DEC rates at current UT. Information is output on the screen.

    • Alternatively, enter target coordinates from an ephemeris file directly on the TCS for the UT closest to the UT time of the observation.

  3. Point to the target and start differential tracking/guiding in either of two ways:

    • Cut and paste the 4 sequencer commands output from tcs.asteph to point and setup for differential tracking and guiding.

    • Alternatively, preset the telescope manually to the target entered in the TCS catalogue. Check that the RA-rate and DEC-rate given in the ephemeris file are in the format needed by the TCS, i.e. dRA/dt without the cos(DEC) correction, otherwise you need to divide the RA-rate by cos(DEC). As soon as the telescope is guiding after pointing to the target, do the following:
      tcs.reposition-guide-probe RA-rate DEC-rate
      and when the telescope is guiding at the differential rates, you can press return in the sequencer window where the OB was started and the observations will start.

    In both cases the star box is placed at the optimal position, the differential tracking and guiding is started. The autoguider box will move at the differential tracking rates and guiding will stop when the box reaches the edge of the monitor (size is 70''). These targets have expected rates below 50''/hour, and the rates typically do not change over the time of the observations. Most likely the whole observation is possible without having to reposition the star box on the autoguider screen, but if you have to reposition, just repeat the above command:
    tcs.reposition-guide-probe RA-rate DEC-rate
    Note that the TCS will give a warning beep when there is 120 sec left before the star box reaches the edge, then again at 90 and 60. Make sure you reposition before the edge is reached.

  4. In order to locate the target, which should be close to the centre of the CCD, you may need a finding chart, especially for spectroscopy. In a browser on the Florence computer to your right, open either of the links:

    Note that for the Lowell astfinder you can enter the target name, set observatory to "950 la Palma", FOV to 390'' for ALFOSC, and you have the possibility to set the time steps of the trajectory, while for AladinLite you have to enter the pointing coordinates.

  5. In addition to comments in the OB queue, remember to fill the ToO tracking log.

No tracking data available