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measures.todoppler - Function

	Package	general
	Module	measures
	Tool	measures

convert a frequency or radialvelocity measure to a doppler measure

Synopsis
todoppler(rf, v0, rfq)

Arguments

rf	in	doppler reference type
		Allowed:	string
v0	in	radial velocity or frequency
		Allowed:	radialvelocity or frequency measure
rfq	in	rest frequency
		Allowed:	frequency measure or frequency quantity
		Default:	F

Returns
frequency measure

Description
todoppler will convert a radialvelocity measure or a frequency measure to a doppler measure. In the case of a frequency, a rest frequency has to be specified. The type of doppler wanted (e.g. RADIO) has to be specified.

Example

- print f := dm.frequency('lsrk','1410MHz')     # specify a frequency
[type=frequency, refer=lsrk, m0=[value=1.41e+09, unit=Hz]]
- dm.todoppler('radio', f, dm.constants('HI')) # give doppler, using HI rest
[type=doppler, refer=radio, m0=[value=2196249.84, unit=m/s]]