The task omsource allows the user to either create or modify an existing source list file by selecting sources on a displayed image. Interactive photometry can be done on the selected sources. The source list file is compatible for use as an input file to the SAS task omsrclistcomb.
omsource needs as input an OM image (IMAGE_) which has undergone the corrections explained in § 6.2.3 and eventually a source list (SWSRLI). A graphical interface and a ds9 type display will be presented to the user. Then, sources on the list can be analysed interactively. The photometry can be re-done and the new values will be incorporated into the source list. Sources can be deleted from the list, and new ones can be added. If no input source list is given, a new one will be created. If desired, then omdetect can be run on the image and the detected sources can be analysed.
Since SAS v7.1 there is a task omphotom intended also for interactive photometry. It does not have a graphical user interface, but it runs from the command line.
omphotom allows the user to recompute the photometry of one or several sources in a list previously obtained with omichain. The aperture and background regions definition can be modified. For crowded fields, a least squares fit to the PSF can be done. This can give better results than the standard mode used in omichain.
The task can accept as input a parameter file that allows specifying several input images and the corresponding source files. This allows batch processing of many exposures in the same observation.
Potential users are referred to the on-line documentation for these two interactive tasks omphotom and omsource.