pint.observatory package

Submodules

pint.observatory.clock_file module

class pint.observatory.clock_file.ClockFile

Bases: object

The ClockFile class provides a way to read various formats of clock files. It will provide the clock information from the file as arrays of times and clock correction values via the ClockFile.time and ClockFile.clock properties. The file should be initially read using the ClockFile.read() method, for example:

>>> cf = ClockFile.read(os.getenv('TEMPO')+'/clock/time_gbt.dat')
>>> print cf.time
[ 51909.5  51910.5  51911.5 ...,  57475.5  57476.5  57477.5]
>>> print cf.clock
[-3.14  -3.139 -3.152 ...,  0.179  0.185  0.188] us

Or:

>>> cf = ClockFile.read(os.getenv('TEMPO2')+'/clock/gbt2gps.clk',
                            format='tempo2')
>>> print cf.time
[ 51909.5  51910.5  51911.5 ...,  57411.5  57412.5  57413.5]
>>> print cf.clock
[ -3.14000000e-06  -3.13900000e-06  -3.15200000e-06 ...,   1.80000000e-08
   2.10000000e-08   2.30000000e-08] s

evaluate(t, limits='warn')

Evaluate the clock corrections at the times t (given as an array-valued Time object). By default, values are linearly interpolated but this could be overridden by derived classes if needed. The first/last values will be applied to times outside the data range. If limits==’warn’ this will also issue a warning. If limits==’error’ an exception will be raised.

classmethod read(filename, format='tempo', **kwargs)

clock

time

class pint.observatory.clock_file.ClockFileMeta(name, bases, members)

Bases: type

Metaclass that provides a registry for different clock file formats. ClockFile implementations should define a ‘format’ class member giving the name of the format.

class pint.observatory.clock_file.Tempo2ClockFile(filename, **kwargs)

Bases: pint.observatory.clock_file.ClockFile

static load_tempo2_clock_file(filename)

Reads a tempo2-format clock file. Returns three values: (mjd, clk, hdrline). The first two are float arrays of MJD and clock corrections (seconds). hdrline is the first line of the file that specifies the two clock scales connected by the file.

format = 'tempo2'

class pint.observatory.clock_file.TempoClockFile(filename, obscode=None, **kwargs)

Bases: pint.observatory.clock_file.ClockFile

static load_tempo1_clock_file(filename, site=None)

Given the specified full path to the tempo1-format clock file, will return two numpy arrays containing the MJDs and the clock corrections (us). All computations here are done as in tempo, with the exception of the ‘F’ flag (to disable interpolation), which is currently not implemented.

INCLUDE statments are processed.

If the ‘site’ argument is set to an appropriate one-character tempo site code, only values for that site will be returned, otherwise all values found in the file will be returned.

format = 'tempo'

pint.observatory.nicer_obs module

class pint.observatory.nicer_obs.NICERObs(name, FPorbname)

Bases: pint.observatory.special_locations.SpecialLocation

Observatory-derived class for the NICER photon data.

Note that this must be instantiated once to be put into the Observatory registry.

posvel(t, ephem)

Return position and velocity vectors of NICER.

t is an astropy.Time or array of astropy.Times

earth_location

tempo_code

timescale

pint.observatory.nicer_obs.load_FPorbit(orbit_filename)

Load data from an (RXTE or NICER) FPorbit file

Reads a FPorbit FITS file

orbit_filename : str

Name of file to load

astropy Table containing Time, x, y, z, v_x, v_y, v_z data

pint.observatory.observatories module

pint.observatory.observatory module

class pint.observatory.observatory.Observatory(name, aliases=None)

Bases: object

The Observatory class defines observatory locations and related site-dependent properties (eg, TOA time scales, clock corrections). Any new Observtory that is declared will be automatically added to a registry that is keyed on observatory name. Aside from their initial declaration (for examples, see pint/observatory/observatories.py), Observatory instances should generally be accessed only via the Observatory.get() function. This will query the registry based on observatory name (and any defined aliases). A list of all registered names can be returned via Observatory.names().

clock_corrections(t)

Given an array-valued Time, return the clock corrections as a numpy array, with units. These values are to be added to the raw TOAs in order to refer them to the timescale specified by self.timescale.

classmethod get(name)

Returns the Observatory instance for the specified name/alias. If the name has not been defined, an error will be raised. Aside from the initial observatory definitions, this is in general the only way Observatory objects should be accessed. Name-matching is case-insensitive.

classmethod names()

posvel(t, ephem)

Returns observatory position and velocity relative to solar system barycenter for the given times (astropy array-valued Time objects).

aliases

earth_location

Returns observatory geocentric position as an astropy EarthLocation object. For observatories where this is not relevant, None can be returned.

name

timescale

Returns the timescale that TOAs from this observatory will be in, once any clock corrections have been applied. This should be a string suitable to be passed directly to the scale argument of astropy.time.Time().

pint.observatory.observatory.get_observatory(name, include_gps=True, include_bipm=True)

Conviencience function to get observatory object with options.

This function will simply call the Observatory.get method but will manually set options after the method is called.

Required arguments:

name = The name of the observatory

Optional Arguments

include_gps = Set False to disable UTC(GPS)->UTC clock

correction.

include_bipm = Set False to disable TAI TT(BIPM) clock

correction.

Note

This function can and should be expanded if more clock file switches/options are added at a public API level.

pint.observatory.special_locations module

class pint.observatory.special_locations.BarycenterObs(name, aliases=None)

Bases: pint.observatory.special_locations.SpecialLocation

Observatory-derived class for the solar system barycenter. Time scale is assumed to be tdb.

posvel(t, ephem)

tempo2_code

tempo_code

timescale

class pint.observatory.special_locations.GeocenterObs(name, aliases=None)

Bases: pint.observatory.special_locations.SpecialLocation

Observatory-derived class for the Earth geocenter.

posvel(t, ephem)

earth_location

tempo2_code

tempo_code

timescale

class pint.observatory.special_locations.SpecialLocation(name, aliases=None)

Bases: pint.observatory.observatory.Observatory

Observatory-derived class for special sites that are not really observatories but sometimes are used as TOA locations (eg, solar system barycenter). Currently the only feature of this class is that clock corrections are zero.

clock_corrections(t)

pint.observatory.topo_obs module

class pint.observatory.topo_obs.TopoObs(name, tempo_code=None, itoa_code=None, aliases=None, itrf_xyz=None, clock_file='time.dat', clock_dir='PINT', clock_fmt='tempo', include_gps=True, include_bipm=True)

Bases: pint.observatory.observatory.Observatory

Class for representing observatories that are at a fixed location on the surface of the Earth. This behaves very similarly to “standard” site definitions in tempo/tempo2. Clock correction files are read and computed, observatory coordinates are specified in ITRF XYZ, etc.

Required arguments:

name = The name of the observatory itrf_xyz = IRTF site coordinates (len-3 array). Can include

astropy units. If no units are given, meters are assumed.

Optional arguments:

tempo_code = 1-character tempo code for the site. Will be

automatically added to aliases. Note, this is REQUIRED only if using TEMPO time.dat clock file.

itoa_code = 2-character ITOA code. Will be added to aliases. aliases = List of other aliases for the observatory name. clock_file = Name of the clock correction file.

Default=’time.dat’

clock_dir = Location of the clock file. Special values

‘TEMPO’, ‘TEMPO2’, or ‘PINT’ mean to use the standard directory for the package. Otherwise can be set to a full path to the directory containing the clock_file. Default=’TEMPO’

clock_fmt = Format of clock file (see ClockFile class for allowed

values). Default=’tempo’

include_gps = Set False to disable UTC(GPS)->UTC clock

correction.

include_bipm = Set False to disable TAI TT(BIPM) clock

correction.

clock_corrections(t)

posvel(t, ephem)

bipm_fullpath

Returns full path to the TAI TT(BIPM) clock file. Will first try PINT data dirs, then fall back on $TEMPO2/clock.

clock_fullpath

Returns the full path to the clock file.

earth_location

gps_fullpath

Returns full path to the GPS-UTC clock file. Will first try PINT data dirs, then fall back on $TEMPO2/clock.

timescale