1.4.1.0 measures.todoppler

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measures.todoppler - Function

1.4.1 convert a frequency or radialvelocity measure to a doppler 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.

Arguments


Inputs
rf	doppler reference type
	allowed:	string
	Default:
v0	radial velocity or frequency measure
	allowed:	record
	Default:
rfq	rest frequency (frequency measure or frequency quantity)
	allowed:	any
	Default:	variant

Returns
record

Example

print "\t----\t todoppler Ex 1 \t----"
f = me.frequency(’lsrk’,’1410MHz’) # specify a frequency
print f
#{’m0’: {’value’: 1410000000.0, ’unit’: ’Hz’},
# ’refer’: ’LSRK’,
# ’type’: ’frequency’}
print me.todoppler(’radio’, f, qa.constants(’HI’)) # give doppler, using HI rest
#{’m0’: {’value’: 2196249.8401180855, ’unit’: ’m/s’},
# ’refer’: ’RADIO’,
# ’type’: ’doppler’}

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