.help aimpars Mar00 astcat
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NAME
aimpars -- Edit the standard image header keyword set
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USAGE
aimpars
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PARAMETERS
.ls 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. 
.le
.ls 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.
.le
.ls 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.
.le
.ls 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.
.le
.ls 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.
.le
.ls 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.
.le
.ls 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.
.le
.ls 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.
.le
.ls 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.
.le
.ls 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.
.le

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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 \fIedatamin\fR, \fIedatamax\fR,
\fIegain\fR, and \fIerdnoise\fR, and parameters required to transform
from mean to observed place \fIobservat\fR, \fIesiteng\fR,
\fIesitelat\fR, \fIesitealt\fR, \fIesitetz\fR, \fIewavlen\fR,
\fIetem\fR, \fIepress\fR. 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.

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EXAMPLES

1. List the default image header parameters.

.nf
cl> lpar aimpars
.fi

2. Edit the default image header parameters.

.nf
cl> aimpars
... edit the parameters in the usual way
... type :wq to quit and save the edits
.fi

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

.nf
cl> epar agetim
... edit the agetim parameters
... move to the agetim parameter line and type :e
... edit the aimpars parameters
... type :wq to quit and save the aimpars edits
... continue editing the remaining aimpars parameters
... type :go to execute the task
.fi

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.

.nf
cl> epar aimpars
... edit some parameters in the usual way
... type :w aimhdr1.par
... type :q to quit
cl> agetim ... aimpars=aimhdr1.par ...

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TIME REQUIREMENTS
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BUGS
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SEE ALSO
agetim
.endhelp
