Subject: World Coordinate Systems standard for All-sky data

From: jjb at beta.lanl.gov (Jeffrey J Bloch)
Date: Sun, 8 Nov 1992 14:11:49 GMT

Newsgroups: sci.fits.astro
Subject: World Coordinate Systems standard for All-sky data
Summary: 
Followup-To: 
Distribution: world
Organization: Los Alamos National Laboratory
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At the ADASS BOF session on World Coordinate Systems, I volunteered to
gather input for Bob Hanisch on the problem of dealing with all-sky data
in the WCS context, namely things such as Hammer-Aitoff maps, Quad Cube
maps, Equal Area Polar (Lambert) maps. For those of us dealing with
generating and distributing all-sky data of moderate resolution and having
existing packages treat these data properly is a real problem. ROSAT, COBE,
GRO, EUVE, and in our case ALEXIS, will all be generating maps covering large
sections of the sky with moderate resolution and demanding some type of
equal area projections. The diffuse X-ray all sky maps from ROSAT will
be generated in equal area polar projections according to Steve Snowden
at MPE. The COBE folks seem to be going with Quad Cube maps. For the
EUV maps generated with the ALEXIS experiment, we are experimenting also
with Quad Cube, and EUVE is using Quad Cube. Neither Lambert or Quad cube
is in the current WCS stanard, and the hooks for dealing with these types
of data may not be there either, or may need some re-interpretation when
dealing with maps of these types. I will be pulsing the people I know on
these projects about their preferences and try to put a proposal for dealing
with these all-sky maps onto this newsgroup in the comming weeks. Please
send me any of your own thoughts on the subject as well.

						Cheers,
						Jeff Bloch
						Astrophysics and Radiation
							Measurement Group
						Los Alamos National Laboratory
						(505)665-2568
						SPAN: ESSDP2::103283
						Internet: 103283 at sstdp2.lanl.gov
						      or: jbloch at alexis.lanl.gov