Enable users to use different survey setups (pixel_scale, psf_fwhm)

LSSTDESC / descwl-shear-sims

simple simulations for testing weak lensing shear measurement

BSD 3-Clause "New" or "Revised" License

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Enable users to use different survey setups (pixel_scale, psf_fwhm) #202

Closed mr-superonion closed 8 months ago

mr-superonion commented 8 months ago

This PR enable users to use different survey setups. related to https://github.com/LSSTDESC/descwl-shear-sims/issues/188

mr-superonion commented 8 months ago

It is still a draft.

mr-superonion commented 8 months ago

@esheldon, @beckermr , can you please review this PR? It enable users to use different survey's pixel scales and magnitude zero points.

mr-superonion commented 8 months ago

Hmm, I think I need more tests before merging... now the code can make simulations for two observations (HSC: left; DES: right) with the same input galaxies. But it seems that there is a shift between the input galaxies on the sky for these two sims.

mr-superonion commented 8 months ago

Let me add a test running the ML detection code and check the centroids have the same sky coords or not..

mr-superonion commented 8 months ago

I think now the sky coordinate matched between the two sims: Right is HSC; left is DES. I would say (hmm...) this is probably ready to merge...

mr-superonion commented 8 months ago

make it easy to simulate CCDs where coadd_dims is not relevant.

Thanks! Hmm, currently, we are using coadd_dims and coadd_pixel_scale, sky_orgin (not implemented, now it is fixed to (WORLD_ORIGIN)) passed to Layout object to define the galaxy distribution (taking flat-sky approximation). At the same time we are using coadd_dims and pixel_scale to define the wcs of the coadd image.

Some possible changes are listed as follows:

use coadd_length in units of arcmin to define the Layout object and remove coadd_dims from the input.
change the make_coadd_dm_wcs(layout, coadd_pixel_scale, coadd_dims) to output a set of wcs for coadd pathches.
enable users to input wcs of single CCD.

esheldon commented 8 months ago

Sorry, I was just discussing these as future possibilities, not for this PR