# Setup

Munipack reads many important data needed for processing from FITS headers. The data are coded in the form KEYWORD=VALUE like a dictionary. Both the keywords and values are standardized, but there is many local conventions and differences and specificatiions in naming KEYWORD conventions. Therefore, there are a list of keywords recognized by Munipack together with default values.

How to set the values for command `munipack` is described in Environment variables document.

A file mostly comply with FITS Standard will not need redefine none of the keywords (except some local conventions).

Just for instance. Many software keeps the exposure time in FITS header in the keyword EXPOSURE. Munipack expects the same quantity in the keyword EXPTIME (see table below). Using of the command

      export FITS_KEY_EXPTIME="EXPOSURE"

replaces the default value. Similar way can be used in all other cases.

## Keywords Affecting Preprocessing

Preprocessing variables
Variable | Default | Description
--- | --- | ---
`MUNIPACK_TEMPERATURE_TOLERANCE` | 1°C | maximal temperature difference between frames in Celsius degrees
`MUNIPACK_EXPTIME_TOLERANCE` | 1 μs | maximal difference between exposure times of frames in seconds

The variables are used by bias, dark and phcorr.

## Keywords Affecting Photometry Calibration

## General Usage Keywords

## FITS environment variables

FITS environment keywords
Variable | Default | Identifies of
--- | --- | ---
`FITS_KEY_FILTER` | `FILTER` | the photometric filter
`FITS_KEY_EXPTIME` | `EXPTIME` | the exposure time
`FITS_KEY_TEMPERATURE` | `TEMPERAT` | the temperature of camera
`FITS_KEY_AIRMASS` | `AIRMASS` | airmass
`FITS_KEY_DATEOBS` | `DATE-OBS` | the start of exposure
`FITS_KEY_TIMEOBS` | `TIME-OBS` | the start of exposure (legacy)
`FITS_KEY_OBJECT` | `OBJECT` | the object identifier
`FITS_KEY_IMAGETYP` | `IMAGETYP` | imagetyp: light, flat, dark
`FITS_KEY_SATURATE` | `SATURATE` | detector saturation (full well capacity) on ADU
`FITS_KEY_READNOISE` | `READNS` | read noise in ADU
`FITS_KEY_GAIN` | `GAIN` | amplifier gain in electrons per ADU
`FITS_KEY_AREA` | `AREA` | area of detector in square meters
`FITS_KEY_EPOCH` | `EPOCH` | reference time epoch
`FITS_KEY_LATITUDE` | `LATITUDE` | geographical latitude of station in degrees, north positive (+north)
`FITS_KEY_LONGITUDE` | `LONGITUD` | geographical longitude of station in degrees, east positive (-west)