The following strings (which are case-insensitive) may be supplied
via the CVT argument to indicate which spectral coordinate
conversion is to be added to the SpecMap. Where arguments are needed by
the conversion, they are listed in parentheses. Values for
these arguments should be given, via the ARGS array, in the
order indicated. Units and argument names are described at the end of
the list of conversions.
-
"FRTOVL" (RF): Convert frequency to relativistic velocity.
-
"VLTOFR" (RF): Convert relativistic velocity to Frequency.
-
"ENTOFR": Convert energy to frequency.
-
"FRTOEN": Convert frequency to energy.
-
"WNTOFR": Convert wave number to frequency.
-
"FRTOWN": Convert frequency to wave number.
-
"WVTOFR": Convert wavelength (vacuum) to frequency.
-
"FRTOWV": Convert fFrequency to wavelength (vacuum).
-
"AWTOFR": Convert wavelength (air) to frequency.
-
"FRTOAW": Convert frequency to wavelength (air).
-
"VRTOVL": Convert radio to relativistic velocity.
-
"VLTOVR": Convert relativistic to radio velocity.
-
"VOTOVL": Convert optical to relativistic velocity.
-
"VLTOVO": Convert relativistic to optical velocity.
-
"ZOTOVL": Convert redshift to relativistic velocity.
-
"VLTOZO": Convert relativistic velocity to redshift.
-
"BTTOVL": Convert beta factor to relativistic velocity.
-
"VLTOBT": Convert relativistic velocity to beta factor.
-
"USF2HL" (VOFF,RA,DEC): Convert frequency from a user-defined
reference frame to heliocentric.
-
"HLF2US" (VOFF,RA,DEC): Convert frequency from heliocentric
reference frame to user-defined.
-
"TPF2HL" (GLON,GLAT,EPOCH,RA,DEC): Convert frequency from
topocentric reference frame to heliocentric.
-
"HLF2TP" (GLON,GLAT,EPOCH,RA,DEC): Convert frequency from
heliocentric reference frame to topocentric.
-
"GEF2HL" (EPOCH,RA,DEC): Convert frequency from geocentric
reference frame to heliocentric.
-
"HLF2GE" (EPOCH,RA,DEC): Convert frequency from
heliocentric reference frame to geocentric.
-
"BYF2HL" (EPOCH,RA,DEC): Convert frequency from
barycentric reference frame to heliocentric.
-
"HLF2BY" (EPOCH,RA,DEC): Convert frequency from
heliocentric reference frame to barycentric.
-
"LKF2HL" (RA,DEC): Convert frequency from kinematic LSR
reference frame to heliocentric.
-
"HLF2LK" (RA,DEC): Convert frequency from heliocentric
reference frame to kinematic LSR.
-
"LDF2HL" (RA,DEC): Convert frequency from dynamical LSR
reference frame to heliocentric.
-
"HLF2LD" (RA,DEC): Convert frequency from heliocentric
reference frame to dynamical LSR.
-
"LGF2HL" (RA,DEC): Convert frequency from local group
reference frame to heliocentric.
-
"HLF2LG" (RA,DEC): Convert frequency from heliocentric
reference frame to local group.
-
"GLF2HL" (RA,DEC): Convert frequency from galactic
reference frame to heliocentric.
-
"HLF2GL" (RA,DEC): Convert frequency from heliocentric
reference frame to galactic.
The units for the values processed by the above conversions are as
follows:
-
all velocities: metres per second (positive if the source receeds from
the observer).
-
frequency: Hertz.
-
all wavelengths: metres.
-
energy: Joules.
-
wave number: cycles per metre.
The arguments used in the above conversions are as follows:
-
RF: Rest frequency (Hz).
-
GLAT: Geodetic latitude of observer (radians).
-
GLON: Geodetic longitude of observer (radians - positive eastwards).
-
EPOCH: Epoch of observation (UT1 expressed as a Modified Julian Date).
-
RA: Right Ascension of source (radians, FK5 J2000).
-
DEC: Declination of source (radians, FK5 J2000).
-
VOFF: Velocity of the user-defined reference frame, towards the
position given by RA and DEC, measured in the heliocentric
reference frame.
If the SpecMap is 3-dimensional, source positions are provided by the
values supplied to inputs 2 and 3 of the SpecMap (which are simply
copied to outputs 2 and 3). Note, usable values are still required
for the RA and DEC arguments in order to define the "user-defined"
reference frame used by USF2HL and HLF2US. However, AST__BAD can be
supplied for RA and DEC if the user-defined reference frame is not
required.