Two new tasks for computing aperture corrections using the growth-curve method, mkapfile and apfile, have been added to the photcal package. See the accompanying article in this Newsletter for a more detailed description of these tasks.
The new Landolt UBVRI (Landolt, A. U. 1992, AJ, 104, 340) and Elias JHKL (Elias et al. 1982, AJ, 87, 1029) standard star catalogs have been added to the photcal standard star catalog library. Assuming that the catalog directory is set to its default value of photcal$catalogs/, the user can access these new catalogs by inputting "nlandolt" or "elias" opposite the ``catalogs'' parameter in the mkconfig, fitparams, invertfit and evalfit tasks.
Support for reading the time of the observations from the input apphot or daophot photometry files and writing it to the output observations files has been added to the mkimsets, mknobsfile/mkobsfile/obsfile, and mkphotcors tasks. The change was made to more easily enable users to check for zero point discontinuities / shifts in their fitted transformations during the course of the night, and to add a UT term to their transformation equations if appropriate. However, as a result of this change the output observations contain a new column not present in observations files created prior to V2.10.3BETA. As a result old configuration files will not work with new observations files, and vice versa, without modification. Old configuration files will still work with old observations files.
A new parameter ``minmagerr'' has been added to the mknobsfile/mkobsfile/obsfile tasks. Non-INDEF valued magnitude measurements with errors less than the current values of ``minmagerr'' are assigned the current value of ``minmagerr''. The new parameter is used to assign a reasonable error to a magnitude measurement when the error is too small to fit in the assigned space in the apphot/daophot database file, and to help prevent the dynamic range of the error measurements from seriously unbalancing the weighting scheme.
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 photcal by retrieving and installing the external layered package digiphotx from our FTP archive.
Lindsey Davis
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