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Daophot - convert pixel values to ra and dec (ZPN system)

phy2j2s wrote on Apr 30, 2009

Hello,

I am not the most experienced user with iraf so sorry if this is very basic.

I have performed my own photometry on a fits file using Daophot (IRAF v2.14.1) following the IRAF/DAOPHOT package reference guide by Lindsey Davis.

I have reached the end of the manual and have created an allstar file (.als) with magnitudes, errors and x/y pixel values. The manual ends at this point with no further instructions.

These images are from the UKIDSS GPS and I need to convert to ra and dec in the ZPN system to make comparisons with the UKIDSS data.

IRAF can handle ZPN on some level as the display output, ximtool (mac), contains both pixels and correct ra and dec.

Thanks for any help

Mike Fitzpatrick wrote on Apr 30, 2009

The FIELDS task can be used to extract the columns of (x,y) positions, then use the WCSCTRAN task to convert those 'logical' coords to 'world' coords using the image. See the help page (esp. the examples) for details.

-Mike

Last post on Apr 30, 2009