measures

class measures[source]

measures tool

Methods Summary

addxvalue

get some additional measure information

asbaseline

define a baseline from a position measure

baseline

define a baseline measure

cometangdiam

get the angular diameter of the current comet in the current frame

cometdist

get the distance of the current comet in the current frame

cometname

get the current comet name

comettopo

get the current comet table coordinates

comettype

get the current comet table type

direction

define a direction measure

dirshow

Show direction measure as a string.

doframe

save a measure as frame reference

done

free resources used by tool.

doppler

define a doppler measure

earthmagnetic

define an earthmagnetic measure

epoch

define an epoch measure

expand

expand n positions to n*(n-1)/2 baselines

framecomet

set the current comet table

framenow

set the active frame time at now

frequency

define a frequency measure

getoffset

get the offset of a measure

getref

get the reference code of a measure

gettype

get the type of a measure

getvalue

get the value of a measure

ismeasure

Check if measure

linelist

get a list of known spectral lines

listcodes

get known reference code names (list indices do not necessarily correspond to enumeration indices)

measure

convert a measure to another reference

measures

Construct measures tool

observatory

get position of an observatory

obslist

get a list of known observatories

posangle

get position angle of two directions

position

define a position measure

radialvelocity

define a radialvelocity measure

rise

get rise and set sidereal time

riseset

get rise and set times

separation

get separation angle between two directions

shift

Shift a direction measure by an offset angle at a position angle.

show

Show a measure as a string

showframe

show the currently active frame reference

source

get direction of a source

sourcelist

get a list of known sources

spectralline

get frequency of a spectral line

todoppler

convert a frequency or radialvelocity measure to a doppler measure

tofrequency

convert a doppler type value to a frequency

toradialvelocity

convert a doppler type value to a real radial velocity

torestfrequency

convert a frequency and doppler measure to a rest frequency

touvw

calculate a uvw measure from a baseline

type

type of tool

uvw

define a uvw measure

addxvalue(a='')[source]

get some additional measure information

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

asbaseline(pos='')[source]

define a baseline from a position measure

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

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

define a baseline measure

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 casawith:

print ” —- baseline Ex 1 —-” 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

cometangdiam()[source]

get the angular diameter of the current comet in the current frame

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]

get the distance of the current comet in the current frame

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]

get the current comet name

cometname gets the name of the current comet (if any).

comettopo()[source]

get the current comet table coordinates

comettopo gets the comet table’s topographic coordinates used.

comettype()[source]

get the current comet table type

comettype gets the comet table type (apparent or topocentric)

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

define a direction measure

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: {em 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 casawith:

egin{verbatim} print ” —- direction Ex 1 —-” 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’]} end{verbatim}

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

dirshow(v='')[source]

Show direction measure as a string.

dirshow will convert a direction measure to a string

Parameters

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

doframe(v='')[source]

save a measure as frame reference

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.{em Epoch}

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

{em 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]

{em Position}

WGS84 ITRF

{em Radial Velocity}

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

{em Doppler}

RADIO OPTICAL Z RATIO RELATIVISTIC BETA GAMMA

{em 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

done()[source]

free resources used by tool.

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]

define a doppler measure

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: {em RADIO Z RATIO BETA GAMMA OPTICAL TRUE RELATIVISTIC}.Note that additional ones may become available. Check in casawith:

egin{verbatim} print ” —- doppler Ex 1 —-” print me.listcodes(me.doppler()) #{‘normal’: [‘RADIO’, ‘Z’, ‘RATIO’, ‘BETA’, ‘GAMMA’, ‘OPTICAL’, # ‘TRUE’, ‘RELATIVISTIC’], ‘extra’: []} end{verbatim}

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

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

define an earthmagnetic measure

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

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

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

define an epoch measure

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: {em UTC TAI LAST LMST GMST1 GAST UT1 UT2 TDT TCG TDB TCB}.Note that additional ones may become available. Check in casawith:

egin{verbatim} print ” —- epoch Ex 1 —-” print me.listcodes(me.epoch()) #{‘normal’: [‘LAST’, ‘LMST’, ‘GMST1’, ‘GAST’, ‘UT1’, ‘UT2’, ‘UTC’, ‘TAI’, # ‘TDT’, ‘TCG’, ‘TDB’, ‘TCB’, ‘IAT’, ‘GMST’, ‘TT’, ‘ET’, ‘UT’], ‘extra’: []} # end{verbatim}

See quantity for possible time formats.

Parameters

  • rf (string='UTC') - reference code

  • v0 (variant='') - epoch value

  • off (record='') - optional offset epoch measure

expand(v='')[source]

expand n positions to n*(n-1)/2 baselines

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 {em xyz} will be set to an array of values.

Parameters

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

framecomet(v='')[source]

set the current comet table

framecomet will put the specified comet table in the frame.

Parameters

  • v (string='') - name of a table

framenow()[source]

set the active frame time at now

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]

define a frequency measure

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: {em REST LSRK LSRD BARY GEO TOPO GALACTO LGROUP CMB}.Note that additional ones may become available. Check in casawith: egin{verbatim} print ” —- frequency Ex 1 —-” print me.listcodes(me.frequency()) #{‘normal’: [‘REST’, ‘LSRK’, ‘LSRD’, ‘BARY’, ‘GEO’, ‘TOPO’, # ‘GALACTO’, ‘LGROUP’, ‘CMB’], ‘extra’: []} end{verbatim}

The frequency quantity values should be in one of the recognised units (examples all give same frequency): egin{itemize} item value with time units: a period (0.5s) item value as frequency: 2Hz item value in angular frequency: 720deg/s item value as length: 149896km item value as wave number: 4.19169e-8m-1 item value as energy (h.nu): 8.27134e-9ueV item value as momentum: 4.42044e-42kg.m end{itemize}

Parameters

  • rf (string='LSRK') - reference code

  • v0 (variant='') - frequency/wavelength/ldots

  • off (record='') - optional offset frequency measure

getoffset(v='')[source]

get the offset of a measure

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

Parameters

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

getref(v='')[source]

get the reference code of a measure

gettype gets the actual reference code of the measure.

Parameters

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

gettype(v='')[source]

get the type of a measure

gettype gets the actual type of the measure.

Parameters

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

getvalue(v='')[source]

get the value of a measure

getvalue gets the actual implementation value of the measure.

Parameters

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

ismeasure(v='')[source]

Check if measure

Checks if the operand is a correct measure

Parameters

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

linelist()[source]

get a list of known spectral lines

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]

get known reference code names (list indices do not necessarily correspond to enumeration indices)

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

measure(v='', rf='', off='')[source]

convert a measure to another reference

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.

{f 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 stagesi.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

measures()[source]

Construct measures tool

Create a measures tool on the specified host (or by default the host you are running on).

observatory(name='ALMA')[source]

get position of an 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): {em’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

obslist()[source]

get a list of known observatories

obslist will give you an array of strings of the observatories known in the Observatories table.

posangle(m1='', m2='')[source]

get position angle of two directions

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)

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

define a position measure

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: {em WGS84 ITRF} (World Geodetic System and International Terrestrial Reference Frame). Note that additional ones may become available. Check in casawith:

egin{verbatim} print ” —- position Ex 1 —-” print me.listcodes(me.position()) #{‘normal’: [‘ITRF’, ‘WGS84’], ‘extra’: []} end{verbatim}

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

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

define a radialvelocity measure

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: {em LSRK LSRD BARY GEO TOPO GALACTO LGROUP CMB}. Note that additional ones may become available. Check in casawith:

egin{verbatim} print ” —- radialvelocity Ex 1 —-” print me.listcodes(me.radialvelocity()) # Out[17]: #{‘extra’: [], # ‘normal’: [‘LSRK’, ‘LSRD’, ‘BARY’, ‘GEO’, ‘TOPO’, ‘GALACTO’, # ‘LGROUP’, ‘CMB’]} end{verbatim} 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

rise(crd='', ev='0.0deg')[source]

get rise and set sidereal time

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

riseset(crd='', ev='0.0deg')[source]

get rise and set times

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

separation(m1='', m2='')[source]

get separation angle between two directions

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)

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

Shift a direction measure by an offset angle at a position angle.

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.

show(v='', refcode=True)[source]

Show a measure as a string

show will convert a measure to a string.

All measures are catered for (at this moment {em 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

showframe()[source]

show the currently active frame reference

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]

get direction of a 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

sourcelist()[source]

get a list of known sources

sourcelist will give you a string with the space separated list of sources known in the Sources table.

spectralline(name='HI')[source]

get frequency of a spectral line

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

Parameters

  • name (string='HI') - name

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

convert a frequency or radialvelocity measure to a doppler measure

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)

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

convert a doppler type value to a frequency

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)

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

convert a doppler type value to a real radial velocity

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

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

convert a frequency and doppler measure to a rest frequency

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

touvw(v='')[source]

calculate a uvw measure from a baseline

touvw calculates a uvw measure from a baseline. Note that the baseline does not have to be a proper {em 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 {em uvw} will be given in J2000. If the {em 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 {em 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

type()[source]

type of tool

type will return the tool name.

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

define a uvw measure

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 casawith: print ” —- uvw Ex 1 —-” 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