PhoSim Tutorial 18: How to Simulate a Scene through the Human Eye

PhoSim can simulate any optical system including biological optical systems like the human eye. This can be used to simulate astronomical objects like those described in the previous tutorials with just "-i eye" applied at the command line. In addition, entire scenes that may not even have an astronomical purpose can be also simulated. This can be done primarily through the fits image format. We made a fits image of the mona lisa image by converting a publicly available jpeg image as shown below (You can convert jpeg to fits images by either using a few lines of IDL or python code or using tools like imagemagick).

PhoSim Mona Lisa Input

To do this, you can use a catalog like the one described below. Here we set the brightness of the overall image to be 0th magnitude, and a 100 second exposure.

rightascension 0.0

declination 0.0

camskyangle 0.0

obstime 100.0

object 0 0.0 0.0 0.0 ../sky/sed_flat.txt 0 0 0 0 0 0 ../../mona-lisa.fits 50.0 0.0 none none

We then used the command line like that shown below

phosim catalog -i eye -c examples/nobackground --ds9

The corresponding simulate image is below. Note there is some photon noise, some aberration near the edges, and an overall flip of the image.

PhoSim Mona Lisa Output