[Comm2011] test plate system in Hercules

[Jeffrey Bout]

Hi all,

I've been looking at the overlaps between generated coadds for
Hercules, which is at a DEC of 17 degrees (much bigger than KIDS).
Coadds with the same declination overlap in RA. Although Hercules is
at DEC=17 degrees, the overlap in RA still does not depend on DEC
within the coadds. The overlap in RA is 2.34 arcmin, slightly less
than the 2.35 arcmin I measured on the equator before (these values
are corrected by cos(DEC)).
For coadds that overlap in DEC, the overlap depends on RA, so whether
you are looking on the left hand side, ride hand side, or the middle
of the overlap. I measered values of 7.25 arcmin (left and right hand
side) to 7.20 arcmin (the middle). These values are also lower than
the 7.45 arcmin I measured before on the equator.
Are these values enough: at least I can say for now: they are still
bigger than the dither spacial variations (1.7arcmin in RA and
5.7arcmin in DEC). So that's nice: the total exposure times at the
overlaps never gets below 'normal' values. But are the overlaps for
example big enough to get good relative photometry between coadds: to
be continued...

Jeffrey