Putting circles around objects with WCS

will.flanagan wrote on May 11, 2009

Hi IRAFers,

I was wondering if anyone knew of a way to put circles around objects in an image that has WCS coordinates by feeding it a list of coordinates.

I'm an IRAF newbie, so links or examples of what to write in the terminal are extremely helpful.

I'm also familiar with SExtractor and WCStools if anyone knows of a way to do it with these tools instead.

Cheers and much thanks for any suggestions!,
Will
CTIO/University of Colorado

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Mike Fitzpatrick wrote on May 11, 2009

The WCSCTRAN task can be used to convert (ra,dec) world coords to (x,y) image coords, you can feed that list then to the TVMARK task to draw circles at those coords in the image display. The FIELDS task is useful for pulling columns out of a text table. You can make all of this a single command using a script, see the script programmer's guide at http://iraf.net/irafdocs/script/ for more information.

-Mike

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will.flanagan wrote on May 11, 2009

Thanks Mike!

That's exactly the sort of thing I was looking for and I noticed that you're the same person that answered my other post - so thanks.

That script programmer's guide should be good because I'm fairly clueless when it come to IRAF scripts.

Cheers,
Will

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Francisco Valdes wrote on May 11, 2009

By the way, there is a script task in the external mscred package that does the two basic steps Mike noted. The task is msctvmark. A layer above that is msczero which loads images, lets you interact in various ways, get a coordinate list from USNO (or possibly other catalog) or a user supplied file, and draw circles. While the package was written for mosaic images it works on single images too.

Frank Valdes

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Last post on May 11, 2009