[fitsbits] Spectral FITS -- encoding extraction area

[Doug Tody]

Hi Tom -

> or something comparable.  I'd like to see just how it is done
> with FITS (e.g., can you mix within one file a binary table and
> a 2-D image array?  not sure I've seen this before ...)

You certainly can.  This is a multi-extension FITS file.  One would use
an image extension or the PDU for an image plane, and a binary table
extension for the encoded pixel mask.  Hopefully someone reading this
will have an actual example of such a file they can point to.

Note there is no real standard for compressed "images" like a pixel
mask.  The paper I referred to earlier (White, Greenfield, Pence, Tody)
was an attempt to define one.  Nonetheless you will find a fair amount
of data around which includes pixel masks of some form or another.

 	- Doug