measures¶

class measures[source]¶

measures tool

Methods Summary

`addxvalue`	addxvalue will give some additional information about some measures as a vector of quantities.
`asbaseline`	asbaseline converts a position measure into a baseline measure.
`baseline`	baseline defines a baseline measure from the CLI.
`cometangdiam`	cometdist returns the angular diameter (as seen from Earth) in AU of the current comet in the current frame, as a quantity.
`cometdist`	cometdist returns the distance in AU of the current comet in the current frame, as a quantity.
`cometname`	cometname gets the name of the current comet (if any).
`comettopo`	comettopo gets the comet table’s topographic coordinates used.
`comettype`	comettype gets the comet table type (apparent or topocentric)
`direction`	direction defines a direction measure from the CLI.
`dirshow`	dirshow will convert a direction measure to a string
`doframe`	doframe will set the measure specified as part of a frame.
`done`	In general you will not want to call this method.
`doppler`	doppler defines a doppler measure from the CLI.
`earthmagnetic`	earthmagnetic defines an earthmagnetic measure from the CLI.
`epoch`	epoch defines an epoch measure from the CLI.
`expand`	expand calculates the differences between a series of given measure values: it calculates baseline values from position values.
`framecomet`	framecomet will put the specified comet table in the frame.
`framenow`	framenow will fill the active frame time with the current date and time.
`frequency`	frequency defines a frequency measure from the CLI.
`getoffset`	getoff gets the actual offset of the measure (as a measure) or F if no offset given.
`getref`	gettype gets the actual reference code of the measure.
`gettype`	gettype gets the actual type of the measure.
`getvalue`	getvalue gets the actual implementation value of the measure.
`ismeasure`	Checks if the operand is a correct measure
`linelist`	linelist will give you a string with a space separated list of spectral lines known in the Lines table.
`listcodes`	listcodes will produce the known reference codes for a specified measure type.
`measure`	measure converts measures (epoch, direction etc.) from one reference to another.
`measures`	Create a measures tool on the specified host (or by default the host you are running on).
`observatory`	observatory will give you the position of an observatory as given in the system. At the time of writing the following observatories are recognised (but check e.g. the position GUI for currently known ones, or the me.obslist() tool function)::.
`obslist`	obslist will give you an array of strings of the observatories known in the Observatories table.
`posangle`	posangle will give the position angle from a direction to another.
`position`	position defines a position measure from the CLI.
`radialvelocity`	radialvelocity defines a radialvelocity measure from the CLI.
`rise`	rise will give the rise/set hour-angles of a source.
`riseset`	rise will give the rise/set times of a source.
`separation`	separation will give the separation of a direction from another as an angle.
`shift`	This method calculates the direction measure located at the specified offset angular amount along the specified position angle from the specified direction measure.
`show`	show will convert a measure to a string.
`showframe`	showframe will display the currently active reference frame values on the terminal.
`source`	source will give you the direction of a source.
`sourcelist`	sourcelist will give you a string with the space separated list of sources known in the Sources table.
`spectralline`	spectralline will give you the frequency of a spectral line.
`todoppler`	todoppler will convert a radialvelocity measure or a frequency measure to a doppler measure.
`tofrequency`	tofrequency will convert a Doppler type value (e.g.
`toradialvelocity`	toradialvelocity will convert a Doppler type value (e.g.
`torestfrequency`	torestfrequency will convert a frequency measure and a doppler measure (e.g.
`touvw`	touvw calculates a uvw measure from a baseline.
`type`	type will return the tool name.
`uvw`	uvw defines a uvw measure from the CLI.

addxvalue(a='')[source]¶

addxvalue will give some additional information about some measures as a vector of quantities. It is used internally to get the rectangular coordinates of measures that are normally given in angles. The casual user will probably in general not interested in this function.

Parameters

a (record='') - measures for which extra information is to be gotten

Returns

record

Examples

print "\t----\t addxvalue Ex 1 \t----"
a=me.observatory('atca')
print a
#{'m0': {'value': 2.6101423190348916, 'unit': 'rad'},
# 'm1': {'value': -0.5261379196128062, 'unit': 'rad'},
# 'm2': {'value': 6372960.2577234386, 'unit': 'm'},
# 'refer': 'ITRF',
# 'type': 'position'}
print me.addxvalue(a)
#{'value': [-4750915.8370000012, 2792906.1819999996, -3200483.747], 'unit': 'm'}
print me.addxvalue(me.epoch('utc','today'))
#{}

asbaseline(pos='')[source]¶

asbaseline converts a position measure into a baseline measure. No actual baseline is calculated, since operations can be done on positions, with subtractions to obtain baselines at a later stage.

Parameters

pos (record='') - position measure

Returns

record

Examples

print "\t----\t asbaseline Ex 1 \t----"

####An example of getting baselines with 3 antenna positions
#### Define the frame ; where, which-direction and when
me.doframe(me.observatory('VLA'))
me.doframe(me.direction('J2000', '19h20m00', '20d10m00'))
me.doframe(me.epoch('utc', '2007/07/08/20:30:00'))

##antenna position
ants=me.position('itrf',qa.quantity([3828763.11,3828746.55, 3828727.43],'m'), qa.quantity([442449.106,442592.14, 442580.12],'m'), qa.quantity([5064923.01, 5064923.01, 5064923.51],'m')) 
print ants
#{'type': 'position', 'refer': 'ITRF', 'm1': {'value': array([ 0.92031276,  0.92031276,  0.92031535]), 'unit': 'rad'}, 
#'m0': {'value': array([ 0.11504897,  0.11508633,  0.1150838 ]), 'unit': 'rad'}, 
#'m2': {'value': array([ 6364639.28758924,  6364639.27051283,  6364627.33064587]), 'unit': 'm'}}

bl=me.asbaseline(ants)
print bl
#{'type': 'baseline', 'refer': 'J2000', 'm1': {'value': array([ 0.92068328,  0.92068326,  0.92068585]), 'unit': 'rad'}, 
#'m0': {'value': array([-2.08658811, -2.08655073, -2.08655326]), 'unit': 'rad'}, 
#'m2': {'value': array([ 6364639.28758924,  6364639.27051283,  6364627.33064587]), 'unit': 'm'}}

me.expand(bl)

#{'return': {'m0': {'unit': 'rad',
#                  'value': array([-0.51637894, -0.36575235,  1.50036599])},
#            'm1': {'unit': 'rad',
#                   'value': array([-0.00060966,  0.00302388,  0.02206414])},
#            'm2': {'unit': 'm',
#                   'value': array([ 143.98943974,  135.78652583,   22.58992696])},
#            'refer': 'J2000',
#            'type': 'baseline'},
# 'xyz': {'unit': 'm',
#         'value': array([  1.25215025e+02,  -7.10925354e+01,  -8.77850493e-02,
#         1.26804339e+02,  -4.85640980e+01,   4.10601842e-01,
#         1.58931410e+00,   2.25284374e+01,   4.98386892e-01])}}

baseline(rf='ITRF', v0='', v1='', v2='', off='')[source]¶

baseline defines a baseline measure from the CLI. It has to specify a reference code, baseline quantity values (see introduction for the action on a scalar quantity with either a vector or scalar value, and when a vector of quantities is given), and optionally it can specify an offset, which in itself has to be a baseline. Allowable reference codes are ITRF and the direction ones.

Note that additional ones may become available. Check in casa with:

print "\t----\t baseline Ex 1 \t----"
print me.listcodes(me.baseline())
# {'normal': array(['J2000', 'JMEAN', 'JTRUE', 'APP', 'B1950', 'B1950_VLA', 'BMEAN',
#       'BTRUE', 'GALACTIC', 'HADEC', 'AZEL', 'AZELSW', 'AZELNE', 'AZELGEO',
#       'AZELSWGEO', 'AZELNEGEO', 'JNAT', 'ECLIPTIC', 'MECLIPTIC',
#       'TECLIPTIC', 'SUPERGAL', 'ITRF', 'TOPO', 'ICRS'], 
#      dtype='|S10'), 'extra': array([], 
#      dtype='|S1')}

The baseline quantity values should be either longitude (angle), latitude(angle) and height(length); or x,y,z (length). See quantity for possible angle formats.

Parameters

rf (string='ITRF') - reference code
v0 (variant='') - longitude or x
v1 (variant='') - latitude or y
v2 (variant='') - height or z
off (record='') - optional offset baseline measure

Returns

record

Examples

print "\t----\t Ex 2 \t----"
print me.baseline('itrf','30deg','40deg','10m')
#{'m0': {'value': 0.52359877559829882, 'unit': 'rad'},
# 'm1': {'value': 0.6981317007977319, 'unit': 'rad'},
# 'm2': {'value': 9.9999999999999982, 'unit': 'm'},
# 'refer': 'ITRF',
# 'type': 'baseline'}
print me.doframe(me.observatory('atca'))
print me.doframe(me.source('1934-638'))
print me.doframe(me.epoch('utc',qa.unit('today')))
print me.measure(me.baseline('itrf','30deg','40deg','10m'), 'J2000')
#{'m0': {'value': 0.58375325605991979, 'unit': 'rad'},
# 'm1': {'value': 0.69758519780286155, 'unit': 'rad'},
# 'm2': {'value': 9.9999999999999964, 'unit': 'm'},
# 'refer': 'J2000',
# 'type': 'baseline'}

cometangdiam()[source]¶: cometdist returns the angular diameter (as seen from Earth) in AU of the current comet in the current frame, as a quantity. It will return -1 radians on failure!

cometdist()[source]¶: cometdist returns the distance in AU of the current comet in the current frame, as a quantity. It will return -1 AU on failure!

cometname()[source]¶: cometname gets the name of the current comet (if any).

comettopo()[source]¶: comettopo gets the comet table’s topographic coordinates used.

comettype()[source]¶: comettype gets the comet table type (apparent or topocentric)

direction(rf='J2000', v0='', v1='', off='')[source]¶

direction defines a direction measure from the CLI. It has to specify a reference code, direction quantity values (see introduction for the action on a scalar quantity with either a vector or scalar value),

and optionally it can specify an offset, which in itself has to be a direction. Allowable reference codes are: J2000 JMEAN JTRUE APP B1950 BMEAN BTRUE GALACTIC HADEC AZEL SUPERGAL ECLIPTIC MECLIPTIC TECLIPTIC MERCURY VENUS MARS JUPITER SATURN URANUS NEPTUNE PLUTO MOON SUN COMET. Note that additional ones may become available. Check in with:

print "\t----\t direction Ex 1 \t----"
print me.listcodes(me.direction())
#{'normal': ['J2000', 'JMEAN', 'JTRUE', 'APP', 'B1950', 'BMEAN',
#'BTRUE', 'GALACTIC', 'HADEC', 'AZEL', 'AZELSW', 'AZELNE', 'AZELGEO',
#'AZELSWGEO', 'AZELNEGEO', 'JNAT', 'ECLIPTIC', 'MECLIPTIC',
#'TECLIPTIC', 'SUPERGAL', 'ITRF', 'TOPO', 'ICRS'], 'extra': ['MERCURY',
#'VENUS', 'MARS', 'JUPITER', 'SATURN', 'URANUS', 'NEPTUNE', 'PLUTO',
#'SUN', 'MOON', 'COMET']}

The direction quantity values should be longitude(angle) and latitude(angle) (none needed for planets: the frame epoch defines coordinates). See quantity for possible angle formats.

Parameters

rf (string='J2000') - reference code
v0 (variant='') - longitude
v1 (variant='') - latitude
off (record='') - optional offset direction measure

Returns

record

Examples

print "\t----\t direction Ex 2 \t----"
print me.direction('j2000','30deg','40deg')
#{'m0': {'value': 0.52359877559829882, 'unit': 'rad'},
# 'm1': {'value': 0.69813170079773168, 'unit': 'rad'},
# 'refer': 'J2000',
# 'type': 'direction'}
#
print me.direction('mars')
#{'m0': {'value': 0.0, 'unit': 'rad'},
# 'm1': {'value': 1.5707963267948966, 'unit': 'rad'},
# 'refer': 'MARS',
# 'type': 'direction'}

dirshow(v='')[source]¶

dirshow will convert a direction measure to a string

Parameters

v (record='') - a direction measure value to be converted to string

Returns

string

Examples

print "\t----\t dirshow Ex 1 \t----"
print me.dirshow(me.direction('venus'))
#[0, 90] deg  VENUS

doframe(v='')[source]¶

doframe will set the measure specified as part of a frame.

If conversion from one type to another is necessary, with the measure function, the following frames should be set if one of the reference types involved in the conversion is as in the following lists. Epoch

UTC TAI LAST position LMST position GMST1 GAST UT1 UT2 TDT TCG TDB TCD

Direction

J2000 JMEAN epoch JTRUE epoch APP epoch B1950 BMEAN epoch BTRUE epoch GALACTIC HADEC epoch position AZEL epoch position SUPERGALACTIC ECLIPTIC MECLIPTIC epoch TECLIPTIC epoch PLANET epoch [position]

Position

WGS84 ITRF

Radial Velocity

LSRK direction LSRD direction BARY direction GEO direction epoch TOPO direction epoch position GALACTO direction

Doppler

RADIO OPTICAL Z RATIO RELATIVISTIC BETA GAMMA

Frequency

REST direction radialvelocity LSRK direction LSRD direction BARY direction GEO direction epoch TOPO direction epoch position GALACTO

Parameters

v (record='') - measure to be set in frame

Returns

bool

Examples

print "\t----\t doframe Ex 1 \t----"
a = me.epoch('utc', 'today')                         # a time
print a
#{'m0': {'value': 54054.91671484954, 'unit': 'd'},
# 'refer': 'UTC',
# 'type': 'epoch'}
print me.doframe(a)                                  # set time in frame
#True

done()[source]¶: In general you will not want to call this method. It removes and then recreates the default measures tool.

doppler(rf='RADIO', v0='', off='')[source]¶

doppler defines a doppler measure from the CLI. It has to specify a reference code, doppler quantity value (see introduction for the action on a scalar quantity with either a vector or scalar value),

and optionally it can specify an offset, which in itself has to be a doppler. Allowable reference codes are: RADIO Z RATIO BETA GAMMA OPTICAL TRUE RELATIVISTIC. Note that additional ones may become available. Check in with:

print "\t----\t doppler Ex 1 \t----"
print me.listcodes(me.doppler())
#{'normal': ['RADIO', 'Z', 'RATIO', 'BETA', 'GAMMA', 'OPTICAL',
# 'TRUE', 'RELATIVISTIC'], 'extra': []}

The doppler quantity values should be either non-dimensioned to specify a ratio of the light velocity, or in velocity.

Parameters

rf (string='RADIO') - reference code
v0 (variant='') - doppler ratio/velocity
off (record='') - optional offset doppler measure

Returns

record

Examples

Examples both give same doppler:

print "\t----\t doppler Ex 2 \t----"
print me.doppler('radio','0.4')
#{'m0': {'value': 119916983.2, 'unit': 'm/s'},
# 'refer': 'RADIO',
# 'type': 'doppler'}
print me.doppler('radio',qa.mul(qa.quantity('0.4'),qa.constants('c')))
#{'m0': {'value': 119916983.2, 'unit': 'm/s'},
# 'refer': 'RADIO',
# 'type': 'doppler'}

earthmagnetic(rf='IGRF', v0='', v1='', v2='', off='')[source]¶

earthmagnetic defines an earthmagnetic measure from the CLI. It needs a reference code, earthmagnetic quantity values (see introduction for the action on a scalar quantity with either a vector or scalar value) if the reference code is not for a model, and optionally it can specify an offset, which in itself has to be a earthmagnetic. In general you specify a model (IGRF is the default and the only one known) and convert it to an explicit field. (See

http://fdd.gsfc.nasa.gov/IGRF.html

for information on the International Geomagnetic Reference Field). The earthmagnetic quantity values should be either longitude (angle), latitude(angle) and length(field strength); or x,y,z (field). See quantity for possible angle formats.

Parameters

rf (string='IGRF') - reference code
v0 (variant='') - Field strength
v1 (variant='') - longitude
v2 (variant='') - latitude
off (record='') - optional offset earthmagnetic measure

Returns

record

Examples

print "\t----\t earthmagnetic Ex 1 \t----"
print me.earthmagnetic('igrf')
#{'type': 'earthmagnetic', 'refer': 'IGRF', 'm1': {'value': 0.0, 'unit': 'nT'},
# 'm0': {'value': 6.1230317691118855e-23, 'unit': 'nT'},
# 'm2': {'value': 9.9999999999999995e-07, 'unit': 'nT'}}
print me.doframe(me.observatory('atca'))
print me.doframe(me.source('1934-638'))
print me.doframe(me.epoch('utc',qa.unit('today')))
print me.measure(me.earthmagnetic('igrf'), 'j2000')
#{'type': 'earthmagnetic', 'refer': 'J2000',
# 'm1': {'value': -8664.8767628222304, 'unit': 'nT'},
# 'm0': {'value': 50544.054410564473, 'unit': 'nT'},
# 'm2': {'value': 1799.5131920958615, 'unit': 'nT'}}

epoch(rf='UTC', v0='', off='')[source]¶

epoch defines an epoch measure from the CLI. It has to specify a reference code, an epoch quantity value (see introduction for the action on a scalar quantity with either a vector or scalar value),

and optionally it can specify an offset, which in itself has to be an epoch. Allowable reference codes are: UTC TAI LAST LMST GMST1 GAST UT1 UT2 TDT TCG TDB TCB. Note that additional ones may become available. Check in with:

print "\t----\t epoch Ex 1 \t----"
print me.listcodes(me.epoch())
#{'normal': ['LAST', 'LMST', 'GMST1', 'GAST', 'UT1', 'UT2', 'UTC', 'TAI',
# 'TDT', 'TCG', 'TDB', 'TCB', 'IAT', 'GMST', 'TT', 'ET', 'UT'], 'extra': []}
#

See quantity for possible time formats.

Parameters

rf (string='UTC') - reference code
v0 (variant='') - epoch value
off (record='') - optional offset epoch measure

Returns

record

Examples

print "\t----\t epoch Ex 2 \t----"
print me.epoch('utc','today') 
#{'m0': {'value': 54048.861237743055, 'unit': 'd'},
# 'refer': 'UTC',
# 'type': 'epoch'}

expand(v='')[source]¶

expand calculates the differences between a series of given measure values: it calculates baseline values from position values. The returned value is a measure, but the value of the optional output variable xyz will be set to an array of values.

Parameters

v (record='') - measure (baseline, position or uvw measure)

Returns

record

Examples

print "\t----\t expand Ex 1 \t----"
b=me.baseline('itrf', qa.quantity([10, 20, 30], 'm'), qa.quantity([10, 20, 30], 'm'), qa.quantity([0, 0, 0], 'm'))
print me.expand(b)
me.expand(b)

#{'return': {'m0': {'unit': 'rad',
#                   'value': array([ 0.78539816,  0.78539816,  0.78539816])},
#            'm1': {'unit': 'rad', 'value': array([ 0.,  0.,  0.])},
#            'm2': {'unit': 'm',
#                   'value': array([ 14.14213562,  28.28427125,  14.14213562])},
#            'refer': 'ITRF',
#            'type': 'baseline'},
# 'xyz': {'unit': 'm',
#         'value': array([ 10.,  10.,   0.,  20.,  20.,   0.,  10.,  10.,   0.])}}

print me.expand(b)['xyz']['value']

#[ 10.  10.   0.  20.  20.   0.  10.  10.   0.]

framecomet(v='')[source]¶

framecomet will put the specified comet table in the frame.

Parameters

v (string='') - name of a table

Returns

bool

Examples

print "\t----\t framecomet Ex 1 \t----"
print me.framecomet('VGEO')
#True
print me.showframe()
#'Frame: VENUS comet between MJD 50802.7 and 50803.1'
print me.cometname()
#'VENUS'
print me.comettype()
#'APP'
print me.doframe(me.epoch('et',qa.quantity('1997/12/20/17:30:0')))
#True
print me.measure(me.direction('comet'),'app')
#{'m0': {'value': -0.94936485919663083, 'unit': 'rad'},
# 'm1': {'value': -0.34710256485894436, 'unit': 'rad'},
# 'refer': 'APP',
# 'type': 'direction'}

framenow()[source]¶: framenow will fill the active frame time with the current date and time. The different frame values necessary are described in the doframe function

frequency(rf='LSRK', v0='', off='')[source]¶

frequency defines a frequency measure from the CLI. It has to specify a reference code, frequency quantity value (see introduction for the action on a scalar quantity with either a vector or scalar value),

and optionally it can specify an offset, which in itself has to be a frequency. Allowable reference codes are: REST LSRK LSRD BARY GEO TOPO GALACTO LGROUP CMB. Note that additional ones may become available. Check in with:

print "\t----\t frequency Ex 1 \t----"
print me.listcodes(me.frequency())
#{'normal': ['REST', 'LSRK', 'LSRD', 'BARY', 'GEO', 'TOPO',
# 'GALACTO', 'LGROUP', 'CMB'], 'extra': []}

The frequency quantity values should be in one of the recognised units (examples all give same frequency):

value with time units: a period (0.5s)
value as frequency: 2Hz
value in angular frequency: 720deg/s
value as length: 149896km
value as wave number: 4.19169e-8m-1
value as energy (h.nu): 8.27134e-9ueV
value as momentum: 4.42044e-42kg.m

Parameters

rf (string='LSRK') - reference code
v0 (variant='') - frequency/wavelength/ldots
off (record='') - optional offset frequency measure

Returns

record

Examples

print "\t----\t frequency Ex 2 \t----"
print me.frequency('lsrk','5GHz')
#{'m0': {'value': 5000000000.0, 'unit': 'Hz'},
# 'refer': 'LSRK',
# 'type': 'frequency'}
print me.frequency('lsrk','21cm')
#{'m0': {'value': 1427583133.3333333, 'unit': 'Hz'},
# 'refer': 'LSRK',
# 'type': 'frequency'}

getoffset(v='')[source]¶

getoff gets the actual offset of the measure (as a measure) or F if no offset given.

Parameters

v (record='') - measure (array of measures)

Returns

record

Examples

print "\t----\t getoffset Ex 1 \t----"
b=me.direction('j2000','0deg','80deg')
print me.getvalue(b)
#{'m0': {'value': 0.0, 'unit': 'rad'},
# 'm1': {'value': 1.3962634015954634, 'unit': 'rad'}}
print me.gettype(b)
#'Direction'
print me.getref(b)
#'J2000'
print me.getoffset(b)
#{}

getref(v='')[source]¶

gettype gets the actual reference code of the measure.

Parameters

v (record='') - measure (array of measures)

Returns

string

Examples

print "\t----\t getref Ex 1 \t----"
b=me.direction('j2000','0deg','80deg')
print me.getvalue(b)
#{'m0': {'value': 0.0, 'unit': 'rad'},
# 'm1': {'value': 1.3962634015954634, 'unit': 'rad'}}
print me.gettype(b)
#'Direction'
print me.getref(b)
#'J2000'

gettype(v='')[source]¶

gettype gets the actual type of the measure.

Parameters

v (record='') - measure (array of measures)

Returns

string

Examples

print "\t----\t gettype Ex 1 \t----"
b=me.direction('j2000','0deg','80deg')
print me.getvalue(b)
#{'m0': {'value': 0.0, 'unit': 'rad'},
# 'm1': {'value': 1.3962634015954634, 'unit': 'rad'}}
print me.gettype(b)
#'Direction'

getvalue(v='')[source]¶

getvalue gets the actual implementation value of the measure.

Parameters

v (record='') - measure (array of measures)

Returns

record

Examples

print "\t----\t getvalue Ex 1 \t----"
b=me.direction('j2000','0deg','80deg')
print me.getvalue(b)
#{'m0': {'value': 0.0, 'unit': 'rad'},
# 'm1': {'value': 1.3962634015954634, 'unit': 'rad'}}

ismeasure(v='')[source]¶

Checks if the operand is a correct measure

Parameters

v (record='') - value to be tested

Returns

bool

Examples

print "\t----\t ismeasure Ex 1 \t----"
x=me.epoch('utc','today')
print x
#{'m0': {'value': 54056.043754386577, 'unit': 'd'},
# 'refer': 'UTC',
# 'type': 'epoch'}
print me.ismeasure(x)
#True
y=me.getvalue(x)
print y
#{'m0': {'value': 54056.043754386577, 'unit': 'd'}}
print me.ismeasure(y)
#False
print "Last example, exiting!"
exit()

linelist()[source]¶

linelist will give you a string with a space separated list of spectral lines known in the Lines table.

A number of lines are available now, but tables with many lines are already online, and will be interfaced once a nomenclature can be defined for the tens of thousands of lines.

listcodes(ms='')[source]¶

listcodes will produce the known reference codes for a specified measure type. It will return a record with two entries. The first is a string vector of all normal codes; the second a string vector (maybe empty) with all extra codes (like planets). NOTE: Synonyms and different code groups may be present in the code name lists. The indices in these lists therefore do not necessarily correspond to the internal CASA enumeration indices.

Parameters

ms (record='') - the measure type for which to list

Returns

record

Examples

print "\t----\t listcodes Ex 1 \t----"
# Generate some direction
# Note that an empty or non-specified reference code will produce the
# measure with the default code for that measure type
a=me.direction()
print me.getref(a)
#'J2000'
print me.ismeasure(a)
#True
# Get the known reference codes for direction
print me.listcodes(a)
# {'normal': array(['J2000', 'JMEAN', 'JTRUE', 'APP', 'B1950', 'B1950_VLA', 'BMEAN',
#       'BTRUE', 'GALACTIC', 'HADEC', 'AZEL', 'AZELSW', 'AZELNE', 'AZELGEO',
#       'AZELSWGEO', 'AZELNEGEO', 'JNAT', 'ECLIPTIC', 'MECLIPTIC',
#       'TECLIPTIC', 'SUPERGAL', 'ITRF', 'TOPO', 'ICRS'], 
#      dtype='|S10'), 'extra': array(['MERCURY', 'VENUS', 'MARS', 'JUPITER', 'SATURN', 'URANUS',
#       'NEPTUNE', 'PLUTO', 'SUN', 'MOON', 'COMET'], 
#      dtype='|S8')}

measure(v='', rf='', off='')[source]¶

measure converts measures (epoch, direction etc.) from one reference to another. It will, for instance, convert a direction from J2000 to AZEL representation. Its arguments are a measure, an output reference code (see the individual measures for the allowable codes (direction, position, epoch, frequency, doppler, radialvelocity, baseline, uvw, earthmagnetic)), and an optional offset of the same type as the main measure. The offset will be subtracted from the result before it is returned. In some cases (see the individual measures for when), more information than just a reference code is necessary. E.g. the above example of a conversion to AZEL, needs to know for when, and where on Earth we want it. This information is stored in a reference frame. Measures are set in the reference frame with the doframe function. The frame is tool wide.

IMPORTANT NOTE: To get an accurate conversion of solar system objects direction to a celestial frame, one should convert to AZEL or HADEC before to get parallax accounted for. Thus if you want to get the moon’s position in J2000..one would do it in 2 stages i.e (after setting the appropriate frames)

moonazel=me.measure(me.direction(’moon’), ’AZELGEO’) moonJ2000=me.measure(moonazel, ’J2000’)

Parameters

v (record='') - measure to be converted
rf (string='') - output reference code
off (record='') - optional output offset measure

Returns

record

Examples

print "\t----\t measure Ex 1 \t----"
a = me.epoch('utc','today')                          # a time
print a
#{'m0': {'value': 54054.872957673608, 'unit': 'd'},
# 'refer': 'UTC',
# 'type': 'epoch'}
print me.doframe(me.source('1934-638'))
print me.measure(a, 'tai')                                   # convert to IAT
#{'m0': {'value': 54054.873339618054, 'unit': 'd'},
# 'refer': 'TAI',
# 'type': 'epoch'}
print me.doframe(a)                                          # set time in frame
#True
print me.doframe(me.observatory('ALMA'))                     # set position in frame
#True
b=me.direction('j2000', qa.toangle('0h'), '-30deg')  # a direction
print b
#{'m0': {'value': 0.0, 'unit': 'rad'},
# 'm1': {'value': -0.52359877559829882, 'unit': 'rad'},
# 'refer': 'J2000',
# 'type': 'direction'}
print me.measure(b, 'azel')                                  # convert to AZEL
#{'m0': {'value': 1.9244096810822324, 'unit': 'rad'},
# 'm1': {'value': 0.76465385681363052, 'unit': 'rad'},
# 'refer': 'AZEL',
# 'type': 'direction'}
print qa.angle(me.getvalue(me.measure(b,'azel'))['m0'])     # show as angles
#['+110.15.38']
print qa.angle(me.getvalue(me.measure(b,'azel'))['m1'])
#['+043.48.41']


Another example:

print "\t----\t measure Ex 2 \t----"
# Fill the frame with necessary information
print me.doframe(me.epoch('utc','today'))
#True
print me.doframe(me.observatory('ALMA'))
#True
print me.doframe(me.direction('mars'))
#True
a=qa.unit('1GHz')
print a
#{'value': 1.0, 'unit': 'GHz'}
m=me.frequency('lsrk',qa.quantity(qa.getvalue(a),qa.getunit(a)))
print m
#{'m0': {'value': 1000000000.0, 'unit': 'Hz'},
# 'refer': 'LSRK',
# 'type': 'frequency'}
print me.measure(m,'lsrd')
#{'m0': {'value': 1000001766.3928765, 'unit': 'Hz'},
# 'refer': 'LSRD',
# 'type': 'frequency'}

measures()[source]¶: Create a measures tool on the specified host (or by default the host you are running on).

observatory(name='ALMA')[source]¶

observatory will give you the position of an observatory as given in the system. At the time of writing the following observatories are recognised (but check e.g. the position GUI for currently known ones, or the me.obslist() tool function):

{'ALMA' 'ARECIBO' 'ATCA' 'BIMA' 'CLRO' 'DRAO' 'DWL' 'GB' 'GBT' 'GMRT'
 'IRAM PDB' 'IRAM_PDB' 'JCMT' 'MOPRA' 'MOST' 'NRAO12M' 'NRAO_GBT' 'PKS'
 'SAO SMA' 'SMA' 'VLA' 'VLBA' 'WSRT' 'ATF' 'ATA' 'CARMA' 'ACA' 'OSF'
 'OVRO_MMA' 'EVLA' 'ASKAP' 'APEX' 'SMT' 'NRO' 'ASTE' 'LOFAR' 'MeerKAT'
 'KAT-7' 'EVN' 'LWA1' 'PAPER_SA' 'PAPER_GB' 'e-MERLIN' 'MERLIN2'
 'Effelsberg' 'MWA32T' }.

Parameters

name (string='ALMA') - observatory name - case insensitive

Returns

record

Examples

print "\t----\t observatory Ex 1 \t----"
print me.observatory('ATCA')
#{'m0': {'value': 2.6101423190348916, 'unit': 'rad'},
# 'm1': {'value': -0.5261379196128062, 'unit': 'rad'},
# 'm2': {'value': 6372960.2577234386, 'unit': 'm'},
# 'refer': 'ITRF',
# 'type': 'position'}

obslist()[source]¶: obslist will give you an array of strings of the observatories known in the Observatories table.

posangle(m1='', m2='')[source]¶

posangle will give the position angle from a direction to another. I.e. the angle in a direction between the direction to the North pole and the other direction. The posiation angle is calculated in the frame of the first argument. m2 is thus converted to the frame of m1 before calculating the position angle.

Parameters

m1 (record='') - direction of source (direction measure)
m2 (record='') - direction of other source (direction measure)

Returns

record

Examples

print "\t----\t posangle Ex 1 \t----"
a=me.direction('j2000','0deg','70deg')
b=me.direction('j2000','0deg','80deg')
print me.posangle(a,b)
#{'value': -0.0, 'unit': 'deg'}
print me.separation(a,b)
#{'value': 9.9999999999999893, 'unit': 'deg'}
tim=me.epoch('utc','today')
print me.doframe(tim)
#True
pos=me.observatory('ATCA')
print me.doframe(pos)
#True
print me.posangle(a,b)
#{'value': -0.0, 'unit': 'deg'}

###Example of how to calculate the parallactic angle of a given direction on thesky.

###set the frames and epoch

position(rf='WGS84', v0='', v1='', v2='', off='')[source]¶

position defines a position measure from the CLI. It has to specify a reference code, position quantity values (see introduction for the action on a scalar quantity with either a vector or scalar value),

and optionally it can specify an offset, which in itself has to be a position. Allowable reference codes are: WGS84 ITRF (World Geodetic System and International Terrestrial Reference Frame). Note that additional ones may become available. Check in with:

print "\t----\t position Ex 1 \t----"
print me.listcodes(me.position())
#{'normal': ['ITRF', 'WGS84'], 'extra': []}

The position quantity values should be either longitude (angle), latitude(angle) and height(length); or x,y,z (length). See quantity for possible angle formats.

Parameters

rf (string='WGS84') - reference code
v0 (variant='') - longitude or x
v1 (variant='') - latitude or y
v2 (variant='') - height or z
off (record='') - optional offset position measure

Returns

record

Examples

print "\t----\t position Ex 2 \t----"
print me.position('wgs84','30deg','40deg','10m')
#{'m0': {'value': 0.52359877559829882, 'unit': 'rad'},
# 'm1': {'value': 0.6981317007977319, 'unit': 'rad'},
# 'm2': {'value': 9.9999999999999982, 'unit': 'm'},
# 'refer': 'WGS84',
# 'type': 'position'}
print me.observatory('ATCA')
#{'m0': {'value': 2.6101423190348916, 'unit': 'rad'},
# 'm1': {'value': -0.5261379196128062, 'unit': 'rad'},
# 'm2': {'value': 6372960.2577234386, 'unit': 'm'},
# 'refer': 'ITRF',
# 'type': 'position'}

###One can use a quantity-vectors  especially when dealing with multiple antenna positions  for e.g for 3 positions

ants=me.position('itrf',qa.quantity([3828763.11,3828746.55, 3828727.43],'m'), qa.quantity([442449.106,442592.14, 442580.12],'m'), 
             qa.quantity([5064923.01, 5064923.01, 5064923.51],'m')) 

print ants

#{'m0': {'unit': 'rad',
#        'value': array([ 0.11504897,  0.11508633,  0.1150838 ])},
# 'm1': {'unit': 'rad',
#        'value': array([ 0.92031276,  0.92031276,  0.92031535])},
# 'm2': {'unit': 'm',
#        'value': array([ 6364639.28758924,  6364639.27051283,  6364627.33064587])},
# 'refer': 'ITRF',
# 'type': 'position'}

radialvelocity(rf='LSRK', v0='', off='')[source]¶

radialvelocity defines a radialvelocity measure from the CLI. It has to specify a reference code, radialvelocity quantity value (see introduction for the action on a scalar quantity with either a vector or scalar value),

and optionally it can specify an offset, which in itself has to be a radialvelocity. Allowable reference codes are: LSRK LSRD BARY GEO TOPO GALACTO LGROUP CMB. Note that additional ones may become available. Check in with:

print "\t----\t radialvelocity Ex 1 \t----"
print me.listcodes(me.radialvelocity())
#  Out[17]:
#{'extra': [],
# 'normal': ['LSRK', 'LSRD', 'BARY', 'GEO', 'TOPO', 'GALACTO',
# 'LGROUP', 'CMB']}

The radialvelocity quantity values should be given as velocity.

Parameters

rf (string='LSRK') - reference code
v0 (variant='') - radial velocity
off (record='') - optional offset radialvelocity measure

Returns

record

Examples

print "\t----\t radialvelocity Ex 2 \t----"
print me.radialvelocity('lsrk','20km/s')
#  Out[18]:
#{'m0': {'value': 20000.0, 'unit': 'm/s'},
# 'refer': 'LSRK',
# 'type': 'radialvelocity'}

rise(crd='', ev='0.0deg')[source]¶

rise will give the rise/set hour-angles of a source. It needs the position in the frame, and a time. If the latter is not set, the current time will be used.

Parameters

crd (variant='') - direction of source (direction measure)
ev (variant='0.0deg') - elevation angle limit

Returns

record

Examples

# NOT IMPLEMENTED
print "\t----\t rise Ex 1 \t----"
print me.rise(me.direction('sun'))
#[rise=[value=267.12445, unit=deg], set=[value=439.029964, unit=deg]] 
print qa.form.long(me.rise(me.direction('sun')).rise)
#17:48:29.868 
#

riseset(crd='', ev='0.0deg')[source]¶

rise will give the rise/set times of a source. It needs the position in the frame, and a time. If the latter is not set, the current time will be used. The returned value is a record with a ’solved’ field, which is F if the source is always below or above the horizon. In that case the rise and set fields will all have a string value. The record also returns a rise and set record, with ’last’ and ’utc’ fields showing the rise and set times as epochs.

Parameters

crd (variant='') - direction of source (direction measure)
ev (variant='0.0deg') - elevation limit

Returns

record

Examples

# NOT IMPLEMENTED
print "\t----\t riseset Ex 1 \t----"
print me.riseset(me.direction('sun'))                     
#[solved=T,
# rise=[last=[type=epoch, refer=LAST, m0=[value=0.0731388605, unit=d]],
#       utc=[type=epoch, refer=UTC, m0=[value=52085.8964, unit=d]]],
# set=[last=[type=epoch, refer=LAST, m0=[value=0.455732593, unit=d]],
#       utc=[type=epoch, refer=UTC, m0=[value=52086.2779, unit=d]]]] 
print me.riseset(me.direction('sun'), qa.unit('80deg'))                     
#[solved=F,
# rise=[last=below, utc=below],
# set=[last=below, utc=below]] 
print qa.form.long(me.riseset(me.direction('sun')).rise.utc.m0)  
#21:30:47.439 
#

separation(m1='', m2='')[source]¶

separation will give the separation of a direction from another as an angle.

Parameters

m1 (record='') - direction of source (direction measure)
m2 (record='') - direction of other source (direction measure)

Returns

record

Examples

print "\t----\t separation Ex 1 \t----"
a=me.direction('j2000','0deg','70deg')
b=me.direction('j2000','0deg','80deg')
print me.separation(a,b)
#{'value': 9.9999999999999893, 'unit': 'deg'}
tim = me.epoch('utc','today')              # set the time
print me.doframe(tim)
#True
pos = me.observatory('ATCA')               # set where
print me.doframe(pos)
#True
c=me.measure(b,'azel')                     # try with different type
print me.separation(a,c)
#{'value': 10.000000000062277, 'unit': 'deg'}

### the example below is how to calculate 
### the parallactic angle 
me.doframe(me.epoch('utc','2015/06/30/19:30:40')))
me.doframe(me.observatory('ALMA'))
mydir = me.direction('J2000','17h28m00','-28d00m00' )
#convert direction to AZEL
mydirazel=me.measure(mydir, 'AZEL')
hadecpol=me.direction('HADEC', '00h00m00', '90d00m00')
### no need to convert north pole direction to AZEL
### as it will coverted to the frame of mydirazel
parAngle=me.posangle(mydirazel, hadecpol)

shift(v='', offset='0deg', pa='0deg')[source]¶

This method calculates the direction measure located at the specified offset angular amount along the specified position angle from the specified direction measure.

Parameters

v (record='') - The direction measure to shift, represented as a record.
offset (variant='0deg') - The angular offset, represented as a quantity record or string.
pa (variant='0deg') - Position angle of the offset, measured from the positive latitude axis through the positive longitude axis.

Returns

record

Examples

v = me.direction("J2000", "13:22:44", "-50.20.20")
# shift along 4 arcminues at a pa of 30 degrees.
offset = me.shift(v, offset="4arcmin", pa="30deg")

show(v='', refcode=True)[source]¶

show will convert a measure to a string.

All measures are catered for (at this moment direction, position, epoch, radialvelocity, frequency, doppler, baseline, uvw, earthmagnetic ).

Parameters

v (record='') - measure value to be converted to string
refcode (bool=True) - add the reference code to output

Returns

string

Examples

print "\t----\t show Ex 1 \t----"
print me.show(me.frequency('lsrk', qa.constants('HI')))
#1.42041e+09 Hz LSRK
print me.show(me.frequency('lsrk', qa.constants('HI')), refcode=False)
#1.42041e+09 Hz

showframe()[source]¶: showframe will display the currently active reference frame values on the terminal. The different frame values necessary are described in the doframe function. The frame is displayed on the terminal using the formatting as done for the show function.

source(name='1934-638')[source]¶

source will give you the direction of a source. The known list can be obtained by me.sourcelist().

Parameters

name (variant='1934-638') - name

Returns

record

Examples

print "\t----\t source Ex 1 \t----"
print me.source()
print me.source('1934-638')
#  Out[19]:
#{'m0': {'value': -1.1370073467795063, 'unit': 'rad'},
# 'm1': {'value': -1.1119959323803881, 'unit': 'rad'},
# 'refer': 'ICRS',
# 'type': 'direction'}

sourcelist()[source]¶: sourcelist will give you a string with the space separated list of sources known in the Sources table.

spectralline(name='HI')[source]¶

spectralline will give you the frequency of a spectral line. The known list can be obtained by me.linelist().

Parameters

name (string='HI') - name

Returns

record

Examples

print "\t----\t spectralline Ex 1 \t----"
print me.spectralline('HI')
#{'m0': {'value': 1420405751.786, 'unit': 'Hz'},
# 'refer': 'REST',
# 'type': 'frequency'}

todoppler(rf='', v0='', rfq='')[source]¶

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.

Parameters

rf (string='') - doppler reference type
v0 (record='') - radial velocity or frequency measure
rfq (variant='') - rest frequency (frequency measure or frequency quantity)

Returns

record

Examples

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'}

tofrequency(rf='', v0='', rfq='')[source]¶

tofrequency will convert a Doppler type value (e.g. in radio mode) to a frequency. The type of frequency (e.g. LSRK) and a rest frequency (either as a frequency quantity (e.g. qa.constants(’HI’)) or a frequency measure (e.g. me.frequency(’rest’,’5100MHz’)) should be specified

Parameters

rf (string='') - frequency reference type
v0 (record='') - doppler measure value
rfq (record='') - rest frequency (frequency measure or freuency quantity)

Returns

record

Examples

print "\t----\t tofrequency Ex 1 \t----"
a=me.doppler('radio','0.4')
print a
#{'m0': {'value': 119916983.2, 'unit': 'm/s'},
# 'refer': 'RADIO',
# 'type': 'doppler'}
print me.tofrequency('lsrk',a,qa.constants('HI'))
#{'m0': {'value': 852243451.07159996, 'unit': 'Hz'},
# 'refer': 'LSRK',
# 'type': 'frequency'}

toradialvelocity(rf='', v0='')[source]¶

toradialvelocity will convert a Doppler type value (e.g. in radio mode) to a real radialvelocity. The type of velocity (e.g. LSRK) should be specified

Parameters

rf (string='') - radial velocity reference type
v0 (record='') - doppler value measure

Returns

record

Examples

print "\t----\t toradialvelocity Ex 1 \t----"
a = me.doppler('radio','0.4')
print a
#  Out[4]:
#{'m0': {'value': 119916983.2, 'unit': 'm/s'},
# 'refer': 'RADIO',
# 'type': 'doppler'}
print me.toradialvelocity('topo',a)
#{'m0': {'value': 141078803.7647059, 'unit': 'm/s'},
# 'refer': 'TOPO',
# 'type': 'radialvelocity'}

torestfrequency(v0='', d0='')[source]¶

torestfrequency will convert a frequency measure and a doppler measure (e.g. obtained from another spectral line with a known rest frequency) to a rest frequency.

Parameters

v0 (record='') - frequency reference type
d0 (record='') - doppler measure value

Returns

record

Examples

print "\t----\t torestfrequency Ex 1 \t----"
dp = me.doppler('radio', '2196.24984km/s')  # a measured doppler speed 
print dp
#{'m0': {'value': 2196249.8399999999, 'unit': 'm/s'},
# 'refer': 'RADIO',
# 'type': 'doppler'}
f = me.frequency('lsrk','1410MHz')    # a measured frequency
print f
#{'m0': {'value': 1410000000.0, 'unit': 'Hz'},
# 'refer': 'LSRK',
# 'type': 'frequency'}
print me.torestfrequency(f, dp)                   # the corresponding rest frequency
#{'m0': {'value': 1420405751.7854364, 'unit': 'Hz'},
# 'refer': 'REST',
# 'type': 'frequency'}

touvw(v='')[source]¶

touvw calculates a uvw measure from a baseline. Note that the baseline does not have to be a proper baseline, but can be a series of positions (to call positions baselines see asbaseline ) for speed reasons: operations are linear and can be done on positions, which are converted to baseline values at the end (with expand ).

Whatever the reference code of the baseline, the returned uvw will be given in J2000. If the dot argument is given, that variable will be filled with a quantity array consisting of the time derivative of the uvw (note that only the sidereal rate is taken into account; not precession, earth tides and similar variations, which are much smaller). If the xyz variable is given, it will be filled with the quantity values of the uvw measure.

The values of the input baselines can be given as a quantity vector per x, y or z value.

uvw coordinates are calculated for a certain direction in the sky; hence the frame has to contain the direction for the calculation to work. Since the baseline and the sky rotate with respect of each other, the time should be specified as well.

Parameters

v (record='') - baseline measure

Returns

record

Examples

print "\t----\t touvw Ex 1 \t----"
print me.doframe(me.observatory('atca'))
#True
print me.doframe(me.source('1934-638'))
#True
print me.doframe(me.epoch('utc',qa.unit('today')))
#True
b=me.baseline('itrf','10m','20m','30m')
print me.touvw(b)
#{'dot': {'unit': 'm/s',
#         'value': [-0.0011912452908351659,
#                   -0.00098731747136827593,
#                   -0.00048769097314181744]},
# 'return': {'m0': {'value': -0.094777304811312649, 'unit': 'rad'},
#            'm1': {'value': -1.1509286139398101, 'unit': 'rad'},
#            'm2': {'value': 37.416573867739416, 'unit': 'm'},
#            'refer': 'J2000',
#            'type': 'uvw'},
# 'xyz': {'unit': 'm',
#         'value': [15.184026188402472,
#                   -1.4434256399579168,
#                   -34.166677788919138]}}
print me.getvalue(me.touvw(b))
#{'m0': {'value': -0.094777304811312649, 'unit': 'rad'},
# 'm1': {'value': -1.1509286139398101, 'unit': 'rad'},
# 'm2': {'value': 37.416573867739416, 'unit': 'm'}}
print me.getvalue(me.touvw(b))['m0']
#{'value': -0.094777304811312649, 'unit': 'rad'}

###Or when you are dealing with multiple antennas
####set the frame..i,e where, direction and when.
me.doframe(me.observatory('VLA'))
me.doframe(me.direction('J2000', '19h20m00', '20d10m00'))
me.doframe(me.epoch('utc', '2007/07/08/20:30:00'))
####antenna positions 
ants=me.position('itrf',qa.quantity([3828763.11,3828746.55, 3828727.43],'m'), qa.quantity([442449.106,442592.14, 442580.12],'m'), qa.quantity([5064923.01, 5064923.01, 5064923.51],'m')) 
###convert to baseline measures
bl=me.asbaseline(ants)
###convert to uvw
me.touvw(bl)

#{'dot': {'unit': 'm/s',
#         'value': array([ 181.25190155,  -73.29924893,  199.57974846,  181.25985238,
#        -73.29691498,  199.57339353,  181.2583565 ,  -73.29668498,
#        199.57276731])},
# 'return': {'m0': {'unit': 'rad',
#                   'value': array([ 2.21611194,  2.21610131,  2.21609887])},
#            'm1': {'unit': 'rad',
#                   'value': array([ 0.6984441 ,  0.69846521,  0.69846285])},
#            'm2': {'unit': 'm',
#                   'value': array([ 6364639.28758924,  6364639.27051283,  6364627.33064587])},
#            'refer': 'J2000',
#            'type': 'uvw'},
# 'xyz': {'unit': 'm',
#         'value': array([-2931661.69632123,  3894141.52172208,  4092634.20894752,
#       -2931568.34776551,  3894103.64373003,  4092737.08879791,
#       -2931559.14911939,  3894111.22249941,  4092717.89890567])}}


####print the (n-1)n/2 baselines(u,v,w)
me.expand(me.touvw(bl)['return'])['xyz']
#{'unit': 'm',
# 'value': array([  93.34855573,  -37.87799205,  102.8798504 ,  102.54720184,
#        -30.29922267,   83.68995815,    9.19864612,    7.57876938,
#        -19.18989224])}

type()[source]¶: type will return the tool name.

uvw(rf='ITRF', v0='', v1='', v2='', off='')[source]¶

uvw defines a uvw measure from the CLI. It has to specify a reference code, uvw quantity values (see introduction for the action on a scalar quantity with either a vector or scalar value), and optionally it can specify an offset, which in itself has to be a uvw. Allowable reference codes are ITRF and the direction ones.

Note that additional ones may become available. Check in casa with:

print "\t----\t uvw Ex 1 \t----"
print me.listcodes(me.uvw())

{
  'normal': array(['J2000', 'JMEAN', 'JTRUE', 'APP', 'B1950', 'B1950_VLA', 'BMEAN',
                   'BTRUE', 'GALACTIC', 'HADEC', 'AZEL', 'AZELSW', 'AZELNE', 'AZELGEO',
                   'AZELSWGEO', 'AZELNEGEO', 'JNAT', 'ECLIPTIC', 'MECLIPTIC',
                   'TECLIPTIC', 'SUPERGAL', 'ITRF', 'TOPO', 'ICRS'], dtype='|S10'),
  'extra': array([], dtype='|S1')
}

The uvw quantity values should be either longitude (angle), latitude(angle) and height(length); or x,y,z (length). See quantity for possible angle formats.

Parameters

rf (string='ITRF') - reference code
v0 (variant='') - longitude or x
v1 (variant='') - latitude or y
v2 (variant='') - height or z
off (record='') - optional offset uvw measure

Returns

record

Examples

print "\t----\t uvw Ex 2 \t----"
print me.uvw('itrf','30deg','40deg','10m')
#{'m0': {'value': 0.52359877559829882, 'unit': 'rad'},
# 'm1': {'value': 0.6981317007977319, 'unit': 'rad'},
# 'm2': {'value': 9.9999999999999982, 'unit': 'm'},
# 'refer': 'ITRF',
# 'type': 'uvw'}
print me.doframe(me.epoch('utc','today'))
#True
print me.doframe(me.observatory('ALMA'))
#True
print me.doframe(me.direction('mars'))
#True
print me.measure(me.uvw('itrf','30deg','40deg','10m'), 'j2000')
#{'m0': {'value': 0.52321924738347259, 'unit': 'rad'},
# 'm1': {'value': 0.69813169995801672, 'unit': 'rad'},
# 'm2': {'value': 10.0, 'unit': 'm'},
# 'refer': 'J2000',
# 'type': 'uvw'}