[fitsbits] HPX projection

Greetings,

A new draft of "Mapping on the HEALPix grid" by Calabretta & Roukema is
available from http://www.atnf.csiro.au/~mcalabre. Red text indicates
further development since the recent astro-ph preprint.

As this paper presents a new projection, HPX (implemented in
WCSLIB 4.0), for incorporation into the FITS WCS standard, it is
presented here for comment by the FITS community.

For those unfamiliar with the paper, the attached diagram based
on Fig. 2 of Roukema & Lew (astro-ph:200409533), summarises it
succinctly.

(Please note that the ATNF web and ftp servers have downtime scheduled
for 17:00 - 22:00 (+11:00) on 2005/02/11.)

Mark Calabretta
ATNF