The PEST pipeline


This set of pages describes the PEST ‘pipeline’, the set of programs I use for photometry and to produce all the other plots and files needed for planet hunting.  The pipeline is especially tailored for TESS, but I use it for all my other projects as well.


NOTE: 8th October 2020:  The pipeline described here is now superseded.  I have not had time to document the new versions so have not yet made them available.  If you would like to use the new pipeline, please contact me and I will do my best to help.


TESS is more demanding of observers in that;

  • transits are generally shallower, so require better precision
  • the area around the target has to be checked for other stars that could have caused the TESS signal, i.e. Nearby Eclipsing Binaries (NEBs).
  • even stars undetected in the observation (i.e. too dim) may be bright enough to have caused the small TESS signal, so these have to be identified
  • the TESS team requests a sample image file in FITS format with objects mapped to sky coordinates

TESS officially supports another tool, AstroImageJ (AIJ).  Most people on the TESS team use this, but I went a different way because my telescope pointing and guiding is too poor for AIJ to work efficiently.  Also I had already written a tool to quickly optimise the selection of ensemble stars which I want to continue to use.  The PEST pipeline does most of what AIJ does, with several exceptions.  It does not do:

  • transit model fitting
  • de-trending that takes into account the predicted transit (this is a feature that is next on my list of to-dos)

I use the PEST pipeline because:

  • my images tend to be poorly aligned
  • it does auto selection/ optimisation of ensemble stars, and
  • multi-aperture photometry in a single run
  • single-step check for NEBs (rather than needing to be fed coordinates of surrounding stars)
  • observing reports are pre-populated for quick completion
  • there’s less manual intervention so overall it’s quicker

But the pipeline runs only on Linux (but why would you use anything else!) and you need to be comfortable using the command line.  It may be possible to adapt the scripts for Windows but I have not done so.

These pages cover:

  1. Pipeline overview
  2. Preliminaries and Download
  3. C-Munipack
  4. PESTphot
  5. MagPy
  6. The config file
  7. Tips and tricks

You are free to use the pipeline for non-commercial purposes.  If use results in any papers or other publications, please acknowledge me, e.g.  “This research made use of the PEST photometry pipeline by Thiam-Guan Tan;

Obviously I cannot warrant that it will work for you, but if you contact me I will try to help.