PhoSim Tutorial 12: How to Create Custom Moving Objects

Objects that move on long timescales (hours/days/years/centuries) can be handled by simply making two catalogs and changing the right ascension and declination of the object in the second catalog. However, objects that move on short timescales (seconds/minutes) may move enough that its position changes during an exposure. This is particularly true for asteroids, comets, and satellites.

In PhoSim, this is handled by several spatial models. A simple example is a moving point source that is specified by a catalog as:

rightascension 0

declination 0

object 0 0.0 0.0 10 ../sky/sed_flat.txt 0 0 0 0 0 0 movingpoint 10.0 30.0 none none

Here the object will move 10 arcseconds every second in time. The position angle of the motion is 30 degrees. The resulting image is: