Keyword |
Read |
Write |
CTYPEia |
All coordinate systems and projection types
listed in paper III are supported algorithm (the ``-LOG'' algorithm may
also be applied to non-spectral linear axes; the ``-TAB'' algorithm
requires the TabOKTabOK attribute to be set in the FitsChan). |
Determined by the SystemSystem attribute of the
SpecFrame and the nature of the pixel to SpecFrame
MappingMapping. |
CUNITia |
Used to set the Units attribute of
the SpecFrame (note, SpecFrames always have an ``active'' Units attribute
(see astSetActiveUnitastSetActiveUnit). |
Always written. |
PVi_ma |
Used to create the pixel to WCS Mapping (values
are stored as attributes of a GrismMapGrismMap). |
Set from the attributes of the GrismMap, if present, and if set explicitly. |
SPECSYSa |
Used to set the StdOfRestStdOfRest
attribute of the SpecFrame (all systems are supported except CMBDIPOL). |
Set from the StdOfRest attribute of the SpecFrame, but only if it has been
set explicitly. |
SSYSOBSa |
Ignored. |
Never written. |
OBSGEO-X/Y/Z |
Used to set the ObsLonObsLon and
ObsLatObsLat attributes of the Frame (the observers
height above sea level is ignored). |
Set from the ObsLon and ObsLat
attributes of the Frame, if they have been set explicitly (it is
assumed that the observer is at sea level). |
MJD-AVG |
Used to set the EpochEpoch attributes of
the SpecFrame. |
Set from the Epoch attribute of the SpecFrame, if it has
been set explicitly. |
SSYSSRCa |
Used to set the SourceVRFSourceVRF attribute of the
SpecFrame
(all systems are supported except CMBDIPOL). |
Set from the SourceVRF
attribute of the SpecFrame. |
ZSOURCEa |
Used to set the SourceVelSourceVel
attribute of the SpecFrame (the SourceVRF attribute
is first set to the system indicated by the SSYSSRC keyword, and the
ZSOURCE value is then converted to an apparent radial velocity and stored
as the SourceVel attribute). |
Set from the SourceVel attribute of
the SpecFrame, if it has been set explicitly (the SourceVel value is
first converted from apparent radial velocity to redshift). |
VELOSYSa |
Ignored. |
Set from the attributes of the
SpecFrame that define the standard of rest and the observers position. |
RESTFRQa |
Used to set the RestFreqRestFreq
attribute of the SpecFrame. |
Set from the RestFreq attribute of the
SpecFrame, but only if the System attribute is not set to
``WAVE'', ``VOPT'', ``ZOPT'' or ``AWAV'', and only if RestFreq has been set
explicitly. |
RESTWAVa |
Used to set the RestFreq
attribute of the SpecFrame (after conversion from wavelength to frequency). |
Set from the RestFreq attribute of the SpecFrame (after conversion), but only if the
System attribute is set to ``WAVE'', ``VOPT'', ``ZOPT'' or
``AWAV'', and only if RestFreq has been set explicitly. |
CNAMEia |
Used to set the Label attributes of
the WCS Frame keywords. |
Set from the Label attributes of the WCS Frame,
if they have been set explicitly. |