Introduction

This software is for

  1. determining and removing detector distortion
  2. finding a correct detector orientation relative to true North
  3. determining the detector plate scale

This was originally made for the LBTI LMIRcam detector, but is generalizable to any project with reference frames of ideal sources and/or an astrometric field paired with a .csv file of astrometric target locations.

The distortion removal is based on a mapping made from a distribution of empirical sources (like a pinhole grid) and an idealized distribution of point sources with a “perfect” distortion. This is them mapped to a perfect distribution without distortions.

The detector orientation and plate scale is determined by allowing the user to mark the identities of stars in a series of astrometric field frames. Following this, all lengths and angles of non-redundant baselines between pairs of stars is calculated to find both the plate scale and angle relative to true North.

Attribution

Please cite Dewarp Spalding and Stone (2019) if you used this code or distortion corrections generated from it. The BibTeX entry is:

@misc{dewarp,
  author = {{Spalding}, E. and J. {Stone}},
  title = {Dewarp},
  keywords = {Software},
  howpublished = {Astrophysics Source Code Library},
  year = 2019,
  archivePrefix = "ascl",
  eprint = {1907.008},
  adsurl = {https://ui.adsabs.harvard.edu/abs/2019ascl.soft07008S/abstract},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}