PhoSim Instance Catalog Definition

This is the main input file to PhoSim. There are two parts to the instance catalog: the observation parameters and the astrophysical inputs. Neither has any required inputs! PhoSim is fully capable of choosing realistic and self-consistent values, so only use the commands below to specify what is important to your particular simulation.

Observation Parameters

The observation parameters have no required inputs. The values will either be calculated self-consistently from other parameters or chosen from a distribution. 

Standard inputs

The standard inputs are listed below which specify pointing, observation time, camera rotation, filter configuration, and exposure information.  A common method is to choose to either specify ra/dec or alt/az, but not both. However you can choose both as well for certain applications and PhoSim will still function with inconsistent parameters with the MJD/latitude/longitude. Unspecified parameters that cannot be calculated self-consistently are chosen from a distribution.

*Note: For CCD devices this includes read out times between exposures but not the read out time for the last exposure. For CMOS devices, the number of reads is simply X divided by the frame rate that is specific for each device.

Advanced inputs to override self-consistent calculations and distributions

The following sun/moon parameters or environmental parameters listed below would most likely not be used because they can be self-consistently calculated by PhoSim. However, they can be specified and do not have to be consistent for certain studies. For example, you could move the Moon below the horizon even if its not there for a given date/time. Or you could pretend you are an observer waiting for a particular good seeing value or cloud cover by specifying the seeing or cloud cover.

Advanced inputs for detailed instrument configuration

The following bookkeeping and configuration parameters listed below are also optional, but useful for simulation of calibration data (see the walkthrough), naming files, or setting the random number seed.

Astrophysical inputs

The astrophysical inputs have no required inputs, but you will have to do at least one object or catalog command to produce any photons.

Automatic Catalog Generation

There are a series of catalog generating commands that will automatically make a set of stars and galaxies.

Individual Object Specification

For every object you wish to add, put the following line at the end of the instance catalog file. Note: an astrophysical object could be composed of more than one line (e.g. a bulge and disk of a galaxy). This enables complex wavelength-dependent morphologies.