PhoSim Tutorial 13: How to Make a 3 Color Image

Step 1: Creating Catalogs

You can make a three (or more) color image by simulating the same catalog through multiple filters. An example of this is by constructing 3 catalogs as:

Instance Catalog 1

Instance Catalog 2

Instance Catalog 3

The three catalogs just switch the filter, and will have the same stars and galaxies generated since they will have the default random number seed. The filters, in this case, for the default telescope (generic) correspond with B, V, R Johnson-Cousins filters.

Step 2: Running PhoSim

Running the commands:

This will output three images

Step 3: Opening in DS9

Now, combining these three images in DS9 will give us our three colored image:

The corresponding three color image where we have assigned the red/green/blue channels to the B/V/R filters is: