PhoSim Output

PhoSim produces a stream of FITS files as its output in an identical fashion to a real telescope. 

The files use the following conventions:

• The files follow the standard astronomical FITS convention for images.  The FITS header contains basic FITS information, standard astronomical header information (e.g. WCS), and substantial simulation state information.

• PhoSim produces two types of files:  1) one file is produced for each readout amplifier (amplifier images) and 2) a single image is produced with the electrons prior to readout (electron image).

  1. For the amplifier images:   The pixels are always organized in readout order (not necessarily related to the geometric orientation) and the values are given as unsigned integers or signed long integers (depending on the A/D system).  The amplifier files have the naming convention: {instrumentName}_a_{visitID}_{instrumentConfiguration}_{amplifierID}_{exposureID}.fits.gz

  2. For the electron image:   This is the image of the electrons prior to readout, and is often more useful than amplifier images due to its simplicity. This is not possible with real telescopes, but lets the user to avoid routine bias/gain correction and amplifier reconstruction. This file has the naming convention: {instrumentName}_e_{visitID}_{instrumentConfiguration}_{sensorID}_{exposureID}.fits.gz

• The naming convention entries are:  instrumentName is the name of the instrument being simulated (e.g. LSST), visitID is a number to name the exposure sequence, instrumentConfiguration (is a string containing essential information (most likely a filter configuration) (e.g. f2), amplifierID or sensorID is the name of the amplifier or sensor (e.g. R22_S11_C13), and exposureID is the number of exposure in the sequence (e.g. E002)

• FITS files can also be converted into more common formats, such as tiff, jpg, and gif.   See Image Magick, FITS liberator, Astropy, or various online conversion tools.