Galactic extinction coefficient for the medium-band filter

[dr-guangtou]

• Need the filter response curve.
• Integrating the filter against a 7000 K, log Z = -1 F dwarf and a Fitzpatrick (1999) extinction curve, and using the calibration of Schlafly & Finkbeiner (2011) to derive the coefficient.
• Could use the DECaLS results to test the code: https://desi.lbl.gov/trac/wiki/ImagingStandardBandpass [Need DESI login]

[dr-guangtou]

• Change the name of the Merian placeholder model filter response curves.
• Put together the code to estimate the extinction coefficient.
• Test the code using SDSS, DECam, and HSC filters
  • Still not perfect: don't know why there is an offset between the Schlafly & Finkbeiner 2011 calibration. But can use a calibration term to make the values consistent within 0.5%.
• Estimate the values for the Merian placeholder filters