helplog.10: DS9, display, WCS, coordinate display

Frank Valdes wrote on Jan 19, 2005

NUMBER:	10
KEYWORDS:	DS9, display, WCS, coordinate display
DATE:	Wed Jan 19 09:02:12 MST 2005
FROM:	valdes

Q:	When I load a fits image (say, a 2Mass image) from within DS9 (with
	file->open), the cursor on the DS9 display provides the x,y and
	RA,DEC position on the image.

	If instead I use the IRAF/display command to load the same image on
	DS9, then I only get x,y from the cursor, no RA-DEC. Why can't DS9
	read the world coordinates of the image when displayed from IRAF cl?

	Is there a parameter I should update somewhere? 

A:	 When IRAF sends the image WCS to the display server it includes the
	pathname to the image, however DS9 doesn't currently do anything
	with this filename and so only displays the x,y coords and
	approximate pixel value based on the z1/z2 scaling.  When DS9 loads
	the image standalone it's able to read the image pixels/wcs
	directly and makes use of them.  There is no parameter you can set,
	this is a change that needs to be made in DS9 to have it access the
	image when displayed from IRAF.

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Last post on Jan 19, 2005