corrects for ISO velocity towards target:
velcor corrects the wavelengths for the ISO velocity component V
in the line of sight towards the target, due to the combined motions of the
spacecraft and the earth (c is the speed of light):
- the ISO velocity towards target at the beginning, middle and end
of an observation is given in the SPD header
- the middle value TREFDOP2 at the 2nd reference time
TREFCOR2
is used for correction
- typical velocities are in the order of +/-10 [km/sec]
- the resulting wavelengths are heliocentric
Cal-files: none
Help text: IA auto analysis
Example:
IA3 TEST> spd_v = velcor(spd_u)
Message(M): Velocity components: -15.020000 -15.010000 -14.990000 [km/sec]
Message(M): Velocity correction of: -15.010000 [km/sec]
Warning:
The headers of SPD structures derived currently in IA with the DSPD command are
corrupt (TREFDOP2 is equal 0). To correct properly for the
ISO velocity towards target, SPD headers have be overwritten by the headers
of the original pipeline SPDs from CD-ROM:
spd = dspd( erd )
spd_orig = read_fspd(
<spd-filename> )
spd.header = spd_orig.header
Whenever velcor reports a velocity correction of 0.0 [km/sec], check the SPD
header carefully. If necessary, overwrite the SPD header before calling velcor.
