Retrieving image data (FWHM, SSTDEV, etc)

Gabriel wrote on May 28, 2009

Hi,

I'm looking for a task that will automatically search for the following image data: FWHM, sky mean value, sky standard deviation value (SSTDEV) and, if possible, radius of bigger PSF star in the frame.
The firts 3 values I get with 'imexa' + 'm' (sky mean value, SSTDEV) and 'r' (FWHM) key. The last value I usually approximate to 3*FWHM (I also approximate the aperture photometry radius value to FWHM +2).

Thanks!

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Francisco Valdes wrote on May 28, 2009

It sounds like you want to automatically characterize an image. This is usually done with a cataloging program such as SExtractor or ACE. Since you mention IMEXAM, there is a more automated version for characterizing the PSFs in an image call PSFMEASURE. However, the trick is to define the positions to use. A task like DAOFIND might be useful.

Frank Valdes

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Gabriel wrote on May 28, 2009

Thanks Frank,

I've already solved the issue by scripting an iterative process (which uses 'psfmeasure') to automatically get FWHM, SKY MEAN and SSTDEV values from an image frame.

Cheers!
Gabriel

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Last post on May 28, 2009