A new task pcalc, and associated tasks txcalc and tbcalc, have been added to the ptools package. pcalc replaces the value of a numerical field in an apphot or daophot database with the value of a numerical expression composed of field names and constants supplied by the user. Typical applications of pcalc include adding an offset to stellar id fields, shifting the computed stellar coordinates, and correcting the zeropoint of the computed stellar magnitudes.
A new parameter ``expr'' has been added to the pdump and tbdump tasks in order to make the functionality of these tasks for the ST binary tables apphot/daophot database the same as the existing functionality of the txdump task for text apphot and daophot databases. The new parameter permits pdump to select and print records from a database by evaluating a user supplied boolean expression.
A new parameter ``idoffset'' has been added to the prenumber task, and to the associated tasks txrenumber and tbrenumber, in order to permit the renumbering to begin at an arbitrary offset rather then always beginning at one. The new parameter permits groups of stars, for example, artificial stars that have been added to an image, to be easily identified after apphot or daophot databases have been merged and subsequently sorted.
The tasks pappend, txappend, and tbappend have been renamed to pconcat, txconcat, and tbconcat, respectively, but are otherwise unchanged.
Users who have not yet upgraded to IRAF 2.10.3BETA, or who are running IRAF on platforms for which IRAF 2.10.3BETA is not yet available, can acquire the updated version of ptools by retrieving and installing the external layered package digiphotx from our FTP archive.
Lindsey Davis
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