Hi,

I'm looking for a task that can do what 'hselect' does, but inversely. I.e.: I need to WRITE only to a certain column of an '.als' file (the 'MAG' column) a new value (which is the old value + the aperture correction) instead of reading only a certain column (which is what I can do with 'hselect')
I can't use 'mkobsfile' task to perform this aperture correction because I need the output file to be an '.als' file whit all it's columns and data (if there's a task to ONLY perform the aperture correction and end up with an '.als' file, much better!).

Is there a way to do this with an already existing task?

Thanks!

See tasks in the TTOOLS package of TABLES, specifically TCALC will let you create a new column by applying a correction to the MAG column. Tasks like TEDIT will let you do other edits, but .als files are just text tables. You might also check the photometry cookbooks, I seem to remember something about aperture correction but don't quite remember the details.

-Mike

Thanks Mike!

I was just about to post that I found what I was looking for on this post:

http://iraf.net/phpBB2/viewtopic.php?t=81017&start=0&postdays=0&postorder=asc&highlight=aperture+correction

This task does exactly what I needed:

pcalc - Do arithmetic on a list of apphot/daophot tables databases

Cheers!