fastsolve.py / cfastsolve.py

This code uses a technique of phase dispersion minimisation to find the period of an asteroid.

On a CCD image the brightness of an asteroid is typically measured relative to two comparisons stars. From night-to-night as the asteroid moves different comparison stars must be used. fastsolve.py allows for night-to-night magnitude zero-point offsets using a very simple version of the phase dispersion minimisation technique. This assumes that the shape of the light curve does not change from night-to-night (run-to-run). Alternatively, if you are using calibrated photometry then cfastsolve.py should be used (does not allow for night-to-night magnitude zero-point offsets).

Program overview:

• Input a list of the summary.obs files (in file 'obs_list') from up to 20 runs.
  e.g. obslist --> 23_11_01/results.diff
                           23_11_02/results.diff
                           23_11_06/results.diff
  
• On the command line, run:
         fastsolve.py Period PeriodScanFraction NscanBins
  e.g.
         fastsolve.py 0.7 0.1 1000
  

  This will scan over +/- 10% of the period with 1000 increments.

The results are saved in new_model.dat, and various plots are produced:

• best_model.png: The best light curve
• best_phase.png: Plot of the dispersion as a function of phase, identifying the minimised dispersion.
• all_models.png: Plot of each of the individual datasets on top of the best lightcurve, corrected for their magnitude offsets.

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jrl

2020-Jun-17 12:41:02 UTC