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superbit-collaboration / superbit-metacal

Contains a collection of routines used to perform gmix/metacalibration on simulated SuperBIT images
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Bright star masking in OBA #120

Closed sweverett closed 1 year ago

sweverett commented 1 year ago

The brightest stars in our target fields have lots of artifacts due to the optical components of the PSF. SExtractor cannot handle this very well and defines a large number of detections near the bright stars and their diffraction spikes. This will seriously impact our compression ratio unless we are able to predict the masking ahead of time

While we can select on known bright stars for each target & mask once we have a WCS solution, most simple/conservative masking will remove extremely large areas of the image, while aggressive masking will be difficult as we will have to be able to predict & model the extent of the diffraction spike w/o ahead of time

image
sweverett commented 1 year ago

This will now be handled by the new oba/starmask.py module, which requires a new GAIA reference catalog on the qcc (/data/bit/gaia/) with pre-computed SuperBIT filter fluxes in ADU/s

sweverett commented 1 year ago

As our GAIA cat is only a few hundred Megabytes (dec < 30 & mags < 15), we can just load the full thing into memory once and quickly make cuts to only compute the superbit fluxes for a few hundred or thousands stars on the fly