./toolbox
frame_velocity.pro

Last modification date:

Thu Jun 2 23:56:08 2005

frame_velocity

function frame_velocity(data, toframe[, fromframe], [/bootstrap])

Toolbox front-end to chdoppler. Get the velocity of a given frame relative to another frame.

Recognized frames:

• TOPO - topocentric. The observed (sky) frame.
• GEO - geocentric.
• HEL - heliocentric.
• BAR - barycentric.
• LSR - Local standard of rest (kinematic).
• LSD - Dynamic LSR.
• GAL - galactocentric.

Returns

Velocity difference between fromframe and toframe along the line of sight implied by the data header.

Uses

chdoppler decode_veldef

Version

$Id: frame_velocity.pro,v 1.4 2005/04/22 15:14:21 bgarwood Exp $

Parameters
data in, required spectrum	Data container to get pointing direction, time, and telescope location from.
toframe in, required string	The desired frame.
fromframe in, optional string	The originating frame. Defaults to "TOPO".

Keywords
bootstrap in, optional boolean	If set, the data.frame_velocity will be used to get to the frame given in data.velocity_definition. The other data header information will only be used to get to other frames. Bootstraping is desirable because the sdfits tool may not be getting the correct times and positions for each integration - early versions didn't. However, the frame_velocity is correct and can be relied on.