[AstroPy] Past Mention of Source Extractor Command in IRAF?

James Turner jturner at gemini.edu
Tue Apr 28 20:38:31 EDT 2009

> Probably not, but is what you mentioned source extraction? The idea is 
> that you take a picture of some part of the night sky, and then turn it 
> over to the source extractor. It twists, rescales, and turns your image 
> every which way until it matches 10 or more corresponding objects 
> (stars, etc.) in a photographic atlas of some sort. If it looks right,  
> you can then extract information about those objects and maybe others. 
> It's an astrometric tool.

It can identify stars in the image and do photometry (not sure whether
it's any good for extended sources -- I don't do a lot of imaging). I'm
not sure I'd describe source extraction and astrometry as the same thing;
maybe imcoords would be better if you want to do astrometry? Others
may have more expert recommendations.

Either way, "help apphot" and "help imcoords" will tell you more than
I can.


> James Turner wrote:
>>> I believe in some of my exchanges on this mailing list in the last 
>>> many works someone mentioned an IRAF facility akin to what is 
>>> popularly called source extract. Mention was made of what could be 
>>> considered a command name that somehow is used in connection with the 
>>> idea. Does anyone know what that single (command) word was or where I 
>>> would find the extractor topic discussed in IRAF?
>> Is it noao.digiphot.apphot (type "help apphot")?
>> James.

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