GalSim-developers / GalSim-developers/GalSim
Updates to Shapelet.fitImage functionality
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- Dominant language
- Python
- Stars
- 272
- Forks
- 121
- PR merge metrics
- No merged PRs in 30d
Description
The ShapeletFitImage function currently still takes a pixel scale parameter for the WCS. It should be updated to take an arbitrary Jacobian matrix to describe the WCS. It's not a very hard change, but it was big enough that I didn't want to do it as part of #364, which had already grown enormous in its scope.
While I'm at it, I think it would be nice to flesh out the Shapelet stuff in GalSim a bit more to bring over some of the other shapelet code I have. Things like fitting the deconvolved shape given a shapelet vector for the effective PSF, and maybe even fitting one solution using multiple images.
It's all code I already have, so it would be nice to incorporate it into GalSim.
Contributor guide
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by locating ShapeletFitImage and the code that currently converts its pixel scale into a WCS description. Update the API and its callers so an arbitrary Jacobian matrix can describe the WCS, then run the relevant Shapelet and image-fitting tests. The later deconvolution and multi-image ideas are additional scope and need separate design decisions.
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Assessment
- Tech stack
- python
- Domain
- data
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100