In the fake stage we inject synthetic objects into real images, then run photometry on the images to test the detection efficiency and photometric accuracy. Fake is initiated after the camera processing, before the warp stage. The core of the fake processing is handled by ppSim.


(source code)


Edit the ppSim.config file in the recipes configuration directory. The principal recipes are:

ADDFAKES : just insert the fake objects, don't do any photometry.

FAKEPHOT : insert fake objects and perform photometry.


When injecting fake objects, ppSim can use two types of stars:

  1. fake stars at known positions, based on a lookup with getstar to a DVO database defined by PSASTRO.CATDIR
  2. fake stars at fake positions, generated randomly with luminosity distribution based on the recipe -- at the moment, it is tied to the density of stars above, but needs to be adjusted to handle a flat distribution (see ppSimMakeStars.c:106)

In addition, ppSim is performing photometry in two possible ways:

  1. at the locations of the injected fake stars (PHOTOM = true)
  2. at a collection of pre-specified locations (not at the location of fake sources), selected from a DVO database defined by FORCED.CATDIR (FORCED.PHOT = true)

it seems that ppSimLoadSpots.c does not handle the case that FORCED.PHOT = true, but the FORCED.CATDIR does not exist. (or maybe the error is the right thing: if you ask for it, you should at least have an empty dvo db there).


ppSim outfile -seeing 1.00 -input SIMTEST/work/simtest.005.002.75/ -cmf SIMTEST/work/simtest.005.002.75/ -psf SIMTEST/work/simtest.005.002.75/ -recipe PPSIM FAKEPHOT