- Last modification date:
- Fri Feb 27 13:46:53 2015
computes the projected velocity of the telescope wrt
six coordinate systems: geo, helio, bary, lsrk, lsrd, gal
negative velocities mean approach
The standard LSR is defined as follows: the sun moves at 20.0 km/s
toward ra=18.0h, dec=30.0 deg in 1900 epoch coords
Fully vectorized. All three arguments must have the same dimensions.
This code came via e-mail from Carl Heiles via Tom Bania on 11/04/2004.
Updated using code found via google from same source on 11/30/2009.
Previous revision history: carlh 29oct04
- modify this documentation for use by idldoc.
- removed path argument and related code, replaced by obspos
- default position is the GBT.
- Observatory longitude was not being passed to juldaytolmst.
- LSRD added
- Galactocentric added
- Checked against aips++ Measures. Differences were less then 20 m/s in
one test case (less then 10m/s for geo, bary, and lsrk).
- Double precision throughout.
- Relativistic addition of velocities.
- from idpppler_chl; changed calculation epoch to 2000.
- 19nov04: correct bad earth spin calculation
- 7 jun 2005: vectorize to make faster for quantity calculations
- 20 Mar 2007: CH updated documentation
- 08 Feb 2015: CH fixed doppler additions for array inputs. See
annotated statements at end of program.
The velocity in km/s, or as a faction of c if
the keyword /light is specified. the result is a 6-element
vector whose elements are [geo, helio, bary, lsrk, lsrd, gal].
$Id: chdoppler.pro,v 1.7 2009/12/01 17:33:37 bgarwood Exp $
The source ra in decimal hours, equinox 2000
The source dec in decimal hours, equinox 2000
The julian day
[East longitude, latitude] in degrees.
Uses the GBT position if not specified.
When set, returns the
velocity as a fraction of c
Produced by IDLdoc 1.6 on Fri Feb 27 13:47:00 2015