Comparison (with color cut) - Here we compare the photometry of the SDSS
catalog with CFHT calibrated DAOPHOT photometry (25px radius ap). We plot
the chip-to-chip offsets relative to the SDSS catalog for each set of
observations and with g'-r' < 1.0 and g'-r' > 1.0. This is roughly where
Milky Way thin disk stars separate from thick disk and halo stars. The
x-axis is the chip number running from 0 to 35, and the y-axis is the offset in
magnitudes (including the color transformation term). Note the small offset
between chip 8 and 9 (<0.03 mag) for the blue sample and the large offset
between the same chips (>0.05 mag) for the red sample. The explanation is that
the photometric superflat for MegaCam does not correct well for redder
stars.
g' (color cut) Plots
| g'-r' < 1.0 |  |
| g'-r' > 1.0 |  |