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P66-502: Active Asteroids and Other Unusual Solar System Objects

P.I.: Jane Luu

This is a ToO and SoftToO program for non-sidereal targets (rates < 50''/hour). All observations will be triggered via the OB system.

ALFOSC instrument setup:

  • Gr #3
  • Slit_1.0''
  • B(#74), V(#75), R(#76), i(#12)

The corresponding commands to run the tcs.asteph for the different objects are:

  • tcs.asteph -n \"2017 K2\"
  • tcs.asteph -n \"2023 JN16\"
  • tcs.asteph -t comet -n 12P
In the case of spectroscopy, dont forget to set the parallactic angle, i.e. use tcs.asteph -m para -n \"NAME\"

Daytime calibrations:

The standard twilight flats are 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.

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/66-502/
    Do ls -lrt to see the scripts and run them as indicated in the trigger. Note the target "NAME" as given in the trigger for use below.

  2. When the OB generator asks you to do the pointing and differential tracking in another sequencer window , do it as follows:

    • Use tcs.asteph -n "NAME" for imaging OBs
    • Use tcs.asteph -m para -n "NAME" for spectroscopy OBs (parallactic angle)

    this calls up JPL Horizons to get position and RA/DEC rates at the current UT. Check that the output given in the terminal refers to the desired object.

  3. Cut and paste the sequencer commands output from tcs.asteph (the 4 last lines) one by one. The 4th line starts the actual differential tracking and guiding:
    tcs.reposition-guide-probe RA-rate DEC-rate
    and you can check that this is happening by noting that the star box is moved to one edge of the guide TV screen, and the guide star is entered.

  4. Now press return in the sequencer window where the OB was started in order to continue the OB script and start the observations.

    The star box is placed at the optimal position on the guide TV screen, 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.

  • 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.

  • In addition to comments in the OB queue, remember to fill the tracking log of this program.

P66 tracking P67 tracking P68 tracking

Program Tracking
Proposal 66-502
Semester P69: 20240401 - 20241001
Principal Investigator Jane Luu
Programme Active Asteroids and Other Unusual Solar System Objects
Instrument ALFOSC
Time Allocation 2 triggers, 3h per target
Total Nights 6.0h
Type ToO+SoftToO
Notes Override. Follow-up soft triggers during Nordic service or Technical nights
Total Time Spent (hh:mm)
Proposal Date Time Type Targets Files Comments Status
Empty table: no tracking data available (yet)


The above information is collected from the ToO/Mon reports that have been created by the observer.

Should any of the observations have been carried out using the OB system, you will find additional information HERE

Back to top Last modified: April 01 2024