Grab chip zeropoints and correctly scale flux

[sweverett]

Currently injections are all (incorrectly) assuming zeropoints of 30, which is consistent with the input catalog. See Brian's slack comment:

For example for tile DES0347-5540, there's a list file here: /data/des71.a/data/kuropat/balrog_test/y3v02/DES0347-5540/lists/DES0347-5540_r_nullwt-flist-y3v02.dat The first line of this file is: /data/des71.a/data/kuropat/balrog_test/y3v02/DES0347-5540/nullwt-r/D00253910_r_c54_r2366p01_immasked_nullwt.fits 31.70017433166504 So for any r-band flux laid down on expnum 253910 ccnum=54, that flux should be multiplied by pow(10,(31.70017-30)/2.5) = 4.787 and so forth.

This means we need the following changes:

• [ ] Pass data version in bal_config : image
• [ ] New chip method to grab the zeropoint from the .dat file
• [ ] Either scale flux explicitly, or tell galsim to do so (which I prefer) All of this is making me think about how to make Balrog IO more general (see #7), but for now we can assume that the current Balrog image class will really become a Balrog_DES class, or something similar.

[sweverett]

Progress has been made but doesn't align with the above check-boxes. Instead we have:

• Constructed a zeropoint dictionary that has the structure of config.zeropoints[band] = {chip_file : zp}
• Added zeropoint as an optional Chip argument (default of 30.0), and passed the relevant zp

Now the easiest path moving forward will likely be to use the scale_flux parameter in the gal field, as outlined in GalSim demo 11. scale_flux can be calculated and set in the chip init.