id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
1407	MD04 refstack/altstack skycells don't have pixel data in the overlap regions	Michael Wood-Vasey	eugene	"The MD04 reference stacks have blank/NAN regions on the edges.  Is this the disagreement between the tessellations chosen for the warps and for the stacks?  The skycells have 15-pixel boundaries on each side.  If you ask ds9 to line them up according to WCS, you get 30-pixel NaN boundaries between the skycells.

This is true in both the MD04 refstack (0.258""/pix) and the altstack (0.2""/pix).  This is true for both the unconv and conv images.  All have a 15 pixel buffer.  The 0.258""/pix version is this missing more sky.

Is an error in the tessellation specification or in the stacking?

See, e.g.,

skycell.054/MD04.skycell.054.stk.120969.unconv.fits
skycell.055/MD04.skycell.055.stk.120970.unconv.fits

Image attached.  This image looks the same in the refstack or altstack."	defect	new	normal		misc		normal