aimpars: Default image data parameters

Package: astcat

Usage

aimpars

Parameters

observat = "OBSERVAT"

The image header keyword defining the observatory at which the data was taken or the name of the observatory. If the observatory is defined then the keyword "OBSERVAT" is written to the image header if it does not already exist.

esitelng = "INDEF", esitelat = "INDEF"

The image header keywords defining the longitude and latitude of the observatory in degrees or the longitude and latitude values in degrees. If the longitude and latitude are defined the keywords "ESITELNG" and "ESITELAT" are written to the image header if they do not already exist.

esitealt = "INDEF"

The image header keyword defining the altitude of the observatory in meters or the altitude itself in meters. If the altitude is defined the keyword "ESITEALT" is written to the image header if it does not already exist.

esitetz = "INDEF"

The image header keyword defining the timezone of the observatory in hours from the Greenwich meridian or the timezone value in hours from the Greenwich meridian. Positive values correspond to time zones west of the meridian. If the time zone is defined the keyword "ESITETZ" is written to the image header if it does not already exist.

emjdobs = "MJD-OBS"

The image header keyword defining the effective MJD of the observation or the MJD. MJD-OBS normally defines the time of the beginning of the observation. Users may wish to change this value to represent the MJD at mid-exposure. If the effective MJD is defined the keyword "EMJDOBS" is written to the image header if it does not already exist.

edatamin = "INDEF", edatamax = "INDEF"

The image header keywords defining the minimum and maximum good data limits in ADU or the minimum and maximum good data values in ADU. If these limits are defined the keywords "EDATAMIN" and "EDATAMAX" are written to the image header if they do not already exist.

egain = "GAIN", erdnoise = "RDNOISE"

The image header keywords defining the effective gain in electrons per ADU and readout noise in electrons or the gain and readout noise values in electrons per ADU and electrons. If the gain and readout noise are defined the keywords "EGAIN" and "ERDNOISE" are written to the image header if they do not already exist.

ewavlen = "INDEF"

The image header keyword defining the effective wavelength in microns or the effective wavelength value in microns. If the effective wavelength is defined the keyword "EWAVLEN" is written to the image header if it does not already exist.

etemp = "INDEF"

The image header keyword defining the effective temperature in degrees or the effective temperature values in degrees. If the effective wavelength is defined the keyword "ETEMP" is written to the image header it does not already exist.

epress = "INDEF"

The image header keyword defining the effective pressure in millibars or the effective pressure values in millibars. If the effective pressure is defined the keyword "EPRESS" is written to the image header if it does not already exist.

Description

The standard image parameter set is used to encode quantities in the image headers that may be required by the astrometric analysis tasks. The current parameter set divides into two parameter groups: parameters concerned with locating stars in an image and computing accurate pixel coordinates and instrumental magnitudes edatamin, edatamax, egain, and erdnoise, and parameters required to transform from mean to observed place observat, esiteng, esitelat, esitealt, esitetz, ewavlen, etem, epress. The latter group of parameter is required for astrometric analyses carried out in observed place rather than mean place.

If the quantity defined by the aimpars parameter is defined, i.e. the parameter value is an image header keyword which defines a valid value, or the parameter value is itself a valid value, then a keyword with the same name as the parameter name is inserted into the image header, if one with that name does not already exist.

Examples

1. List the default image header parameters.

cl> lpar aimpars

2. Edit the default image header parameters.

cl> aimpars

3. Edit the default image header parameters from the agetim task.

cl> epar agetim

4. Save the current awcspars parameter values in a text file called aimhdr1.par. Use the saved parameter set in the next call to the agetim task.

cl> epar aimpars
cl> agetim ... aimpars=aimhdr1.par ...

Time requirements

Bugs

See also

agetim