This attribute identifies the standard of rest to which the spectral
axis values of a SpecFrame refer, and may take any of the values
listed in the ``Standards of Rest'' section (below).
The default StdOfRest value is "Helio".
Type:
String.
Standards of Rest
:
The SpecFrame class supports the following
StdOfRest values (all are case-insensitive).
"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, 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.
"LSR", "LSRK": 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.
