RMARK: Interactively Set Maximum Radius for EMAG

RMARK enables the user to interactively set the maximum radius for the photometry routine EMAG. The image on which photometry is to be performed must be displayed, and an AXES computation must have been previously performed, in order for RMARK to work.

RMARK will prompt the user to move the cursor to a point at the distance from the object center to which the photometry is to be performed. The user then strikes the key "P". A cross will be displayed at this point and the user will be given the option of choosing another position. Once the user is satisfied with the position chosen, RMARK will compute the distance of this point from the object center. This distance is then loaded into the VISTA variable RMAX.

When RMAX is given as a command line keyword in EMAG, the value of this variable is retrieved and the photometry proceeds out to this radius.