"
Standards of Rest"
section (below).
The default StdOfRest value is "
Helio"
.
"
Topocentric"
, "
Topocent"
or "
Topo"
: The observers rest-frame (assumed to
be on the surface of the earth). Spectra recorded in this standard of rest
suffer a Doppler shift which varies over the course of a day because of the
rotation of the observer around the axis of the earth. This standard of rest
must be qualified using the ObsLat, ObsLon, ObsAlt, Epoch, RefRA and RefDec
attributes.
"
Geocentric"
, "
Geocentr"
or "
Geo"
: The rest-frame of the earth centre. Spectra
recorded in this standard of rest suffer a Doppler shift which varies over the course
of a year because of the rotation of the earth around the Sun. This standard of rest
must be qualified using the Epoch, RefRA and RefDec attributes.
"
Barycentric"
, "
Barycent"
or "
Bary"
: The rest-frame of the solar-system
barycentre. Spectra recorded in this standard of rest suffer a Doppler shift which
depends both on the velocity of the Sun through the Local Standard of Rest, and on the
movement of the planets through the solar system. This standard of rest must be
qualified using the Epoch, RefRA and RefDec attributes.
"
Heliocentric"
, "
Heliocen"
or "
Helio"
: The rest-frame of the Sun. Spectra recorded
in this standard of rest suffer a Doppler shift which depends on the velocity of the
Sun through the Local Standard of Rest. This standard of rest must be qualified using
the RefRA and RefDec attributes.
"
LSRK"
, "
LSR"
: The rest-frame of the kinematical Local Standard of Rest. Spectra
recorded in this standard of rest suffer a Doppler shift which depends on the velocity
of the kinematical Local Standard of Rest through the galaxy. This standard of rest
must be qualified using the RefRA and RefDec attributes.
"
LSRD"
: The rest-frame of the dynamical Local Standard of Rest. Spectra recorded in
this standard of rest suffer a Doppler shift which depends on the velocity of the
dynamical Local Standard of Rest through the galaxy. This standard of rest must be
qualified using the RefRA and RefDec attributes.
"
Galactic"
, "
Galactoc"
or "
Gal"
: The rest-frame of the galactic centre. Spectra
recorded in this standard of rest suffer a Doppler shift which depends on the velocity
of the galactic centre through the local group. This standard of rest must be qualified
using the RefRA and RefDec attributes.
"
Local_group"
, "
Localgrp"
or "
LG"
: The rest-frame of the local group. This
standard of rest must be qualified using the RefRA and RefDec attributes.
"
Source"
, or "
src"
: The rest-frame of the source. This standard of rest must be
qualified using the RefRA, RefDec and SourceVel attributes.
Where more than one alternative System value is shown above, the first of these will be returned when an enquiry is made.