`nifits.io.oifits`¶

A module for reading/writing NIFITS files and handling the data.

To open an existing NIFITS file, use nifits.from_nifits constructor.

To save an NIFITS object to a file, use nifits.to_nifits method.

A summary of the information in the oifits object can be obtained by using the info() method:

> import oifits > oifitsobj = oifits.open(‘foo.fits’) > oifitsobj.info()

For further information, contact R. Laugier

Module Contents¶

Classes¶

`OI_STATION`	This class corresponds to a single row (i.e. single
`NI_CATM`	Contains the complex amplitude transfer matrix CATM of the instrument.
`NI_EXTENSION`	`NI_EXTENSION` Generic class for NIFITS extensions
`NI_EXTENSION_ARRAY`	Generic class for NIFITS array extensions
`NI_EXTENSION_CPX_ARRAY`	Generic class for NIFITS array extensions.
`OI_ARRAY`	`NI_EXTENSION` Generic class for NIFITS extensions
`OI_WAVELENGTH`	`NI_EXTENSION` Generic class for NIFITS extensions
`NI_OSWAVELENGTH`	`NI_EXTENSION` Generic class for NIFITS extensions
`OI_TARGET`	`OI_TARGET` definition.
`NI_CATM`	Contains the complex amplitude transfer matrix CATM of the instrument.
`NI_IOUT`	`NI_EXTENSION` Generic class for NIFITS extensions
`NI_KIOUT`	`NI_EXTENSION` Generic class for NIFITS extensions
`NI_KCOV`	Generic class for NIFITS array extensions
`NI_KMAT`	Generic class for NIFITS array extensions
`NI_DSAMP`	Generic class for NIFITS array extensions
`NI_IOTAGS`	Contains information on the inputs and outputs.
`NI_MOD`	Contains input modulation vector for the given observation. The format
`NI_FOV`	`NI_EXTENSION` Generic class for NIFITS extensions
`nifits`	Class representation of the nifits object.

Functions¶

`check_item`(func)	A decorator for the fits.Header.__getitem__.
`_plurals`(count)
`array_eq`(a, b)	Test whether all the elements of two arrays are equal.
`_isnone`(x)	Convenience hack for checking if x is none; needed because numpy
`_notnone`(x)	Convenience hack for checking if x is not none; needed because numpy
`nulfunc`(self, args, *kwargs)
`create_basic_fov_data`(D, offset, lamb, n)	A convenience function to help define the FOV function and data model
`getclass`(classname)

Attributes¶

`Table`
`ArrayLike`
`__version__`
`__standard_version__`
`_mjdzero`
`matchtargetbyname`
`matchstationbyname`
`refdate`
`NI_OITAG_DEFAULT_HEADER`
`NI_MOD_DEFAULT_HEADER`
`NI_FOV_DEFAULT_HEADER`	Obtaining the goecentric location of observatories. (unchecked)
`OI_ARRAY_DEFAULT_VLTI_HEADER`
`OI_ARRAY_DEFAULT_CHARA_HEADER`
`TEST_BACKUP`
`NIFITS_EXTENSIONS`
`NIFITS_KEYWORDS`
`STATIC_EXTENSIONS`
`H_PREFIX`

nifits.io.oifits.Table[source]¶

nifits.io.oifits.ArrayLike¶

nifits.io.oifits.__version__ = '0.0.6'¶

nifits.io.oifits.__standard_version__ = '0.4'¶

nifits.io.oifits._mjdzero¶

nifits.io.oifits.matchtargetbyname = False¶

nifits.io.oifits.matchstationbyname = False¶

nifits.io.oifits.refdate¶

nifits.io.oifits.check_item(func)[source]¶: A decorator for the fits.Header.__getitem__. This is here to save from compatibility issues with files of standard version <= 0.2 while warning that that this version will

nifits.io.oifits._plurals(count)[source]¶

nifits.io.oifits.array_eq(a: ArrayLike, b: ArrayLike)[source]¶

Test whether all the elements of two arrays are equal.

Parameters:

a – one input.
b – another input.

nifits.io.oifits._isnone(x)[source]¶: Convenience hack for checking if x is none; needed because numpy arrays will, at some point, return arrays for x == None.

nifits.io.oifits._notnone(x)[source]¶: Convenience hack for checking if x is not none; needed because numpy arrays will, at some point, return arrays for x != None.

class nifits.io.oifits.OI_STATION(tel_name=None, sta_name=None, diameter=None, staxyz=[None, None, None], fov=None, fovtype=None, revision=1)[source]¶

Bases: object

This class corresponds to a single row (i.e. single station/telescope) of an OI_ARRAY table.

__eq__(other)[source]¶: Return self==value.

__ne__(other)[source]¶: Return self!=value.

__repr__()[source]¶: Return repr(self).

class nifits.io.oifits.NI_CATM[source]¶

Bases: object

Contains the complex amplitude transfer matrix CATM of the instrument. The CATM is a complex matrix representing the transformation from the each of the complex amplitude of electric field from the inputs to the outputs of the instrument. The dimensions are (n_ch, n_out, n_in) where n_ch represents the spectral channels.

It is expected that

\(\textbf{n}_{out} = \textbf{M}_{CATM}.\textbf{m}_{mod} \circ \textbf{x}_{in}\) with \(\textbf{m}_{mod}\) containded in NI_MOD.

Mcatm: ArrayLike¶

header: astropy.io.fits.Header¶

classmethod from_hdu(hdu: type(fits.hdu.ImageHDU))[source]¶: Create the NI_CATM object from the HDU extension of an opened fits file.

to_hdu()[source]¶: Returns and hdu object to save into fits

nifits.io.oifits.nulfunc(self, *args, **kwargs)[source]¶

nifits.io.oifits.NI_OITAG_DEFAULT_HEADER¶

nifits.io.oifits.NI_MOD_DEFAULT_HEADER¶

nifits.io.oifits.NI_FOV_DEFAULT_HEADER¶: Obtaining the goecentric location of observatories. (unchecked) `python from astroplan import Observer import astropy.coordinates as coords myobs = Observer.at_site("CHARA") print([acoord.value for acoord in myobs.location.to_geocentric()]) ` VLTI: 1946404.3410388362, -5467644.290798524, -2642728.2014442487 CHARA: -2484228.6029109913, -4660044.467216573, 3567867.961141405

nifits.io.oifits.OI_ARRAY_DEFAULT_VLTI_HEADER¶

nifits.io.oifits.OI_ARRAY_DEFAULT_CHARA_HEADER¶

class nifits.io.oifits.NI_EXTENSION[source]¶

Bases: object

NI_EXTENSION Generic class for NIFITS extensions

Inherited methods:

from_hdu: Creates the object from an astropy.io.fits.TableHDU object
to_hdu : Returns the TableHDU from itself.

Parameters:

data_table – [ArrayLike] The data to stored
header – [fits.Header] A fits header (optional)
unit – [astropy.units.Unit] Units of the data stored (mandatory of NI_IOUT, NI_KIOUT and NI_KCOV)

data_table: Table¶

header: astropy.io.fits.Header¶

unit: astropy.units.Unit¶

classmethod from_hdu(hdu: type(fits.hdu.TableHDU))[source]¶

Create the data object from the HDU extension of an opened fits file.

Parameters:: hdu – TableHDU object containing the relevant data

to_hdu()[source]¶: Returns and hdu object to save into fits

__len__()[source]¶

class nifits.io.oifits.NI_EXTENSION_ARRAY[source]¶

Bases: NI_EXTENSION

Generic class for NIFITS array extensions

Parameters:

data_array – [ArrayLike] The data to stored
header – [fits.Header] A fits header (optional)
unit – [astropy.units.Unit] Units of the data stored (mandatory of NI_IOUT, NI_KIOUT and NI_KCOV)

property shape¶

data_array: ArrayLike¶

header: astropy.io.fits.Header¶

unit: astropy.units.Unit¶

classmethod from_hdu(hdu: type(fits.hdu.ImageHDU))[source]¶: Create the data object from the HDU extension of an opened fits file.

to_hdu()[source]¶: Returns and hdu object to save into fits

Note

This also updates the header if dimension changes

__len__()[source]¶

class nifits.io.oifits.NI_EXTENSION_CPX_ARRAY[source]¶

Bases: NI_EXTENSION

Generic class for NIFITS array extensions.

The array is kept locally as complex valued, but it is stored to and loaded from a real-valued array with an extra first dimension of length 2 for (real, imaginary) parts.

property shape¶

data_array: ArrayLike¶

header: astropy.io.fits.Header¶

classmethod from_hdu(hdu: type(fits.hdu.ImageHDU))[source]¶: Create the data object from the HDU extension of an opened fits file.

to_hdu()[source]¶: Returns and hdu object to save into fits

Note

This also updates the header if dimension changes

__len__()[source]¶

class nifits.io.oifits.OI_ARRAY[source]¶

Bases: NI_EXTENSION

NI_EXTENSION Generic class for NIFITS extensions

Inherited methods:

from_hdu: Creates the object from an astropy.io.fits.TableHDU object
to_hdu : Returns the TableHDU from itself.

Parameters:

data_table – [ArrayLike] The data to stored
header – [fits.Header] A fits header (optional)
unit – [astropy.units.Unit] Units of the data stored (mandatory of NI_IOUT, NI_KIOUT and NI_KCOV)

__doc__¶

name = 'OI_ARRAY'¶

class nifits.io.oifits.OI_WAVELENGTH[source]¶

Bases: NI_EXTENSION

NI_EXTENSION Generic class for NIFITS extensions

Inherited methods:

from_hdu: Creates the object from an astropy.io.fits.TableHDU object
to_hdu : Returns the TableHDU from itself.

Parameters:

data_table – [ArrayLike] The data to stored
header – [fits.Header] A fits header (optional)
unit – [astropy.units.Unit] Units of the data stored (mandatory of NI_IOUT, NI_KIOUT and NI_KCOV)

property lambs¶

property dlambs¶

property nus¶

property dnus¶

__doc__¶

name = 'OI_WAVELENGTH'¶

class nifits.io.oifits.NI_OSWAVELENGTH[source]¶

Bases: NI_EXTENSION

NI_EXTENSION Generic class for NIFITS extensions

Inherited methods:

from_hdu: Creates the object from an astropy.io.fits.TableHDU object
to_hdu : Returns the TableHDU from itself.

Parameters:

data_table – [ArrayLike] The data to stored
header – [fits.Header] A fits header (optional)
unit – [astropy.units.Unit] Units of the data stored (mandatory of NI_IOUT, NI_KIOUT and NI_KCOV)

property lambs¶

property dlambs¶

property nus¶

property dnus¶

__doc__¶

name = 'OI_WAVELENGTH'¶

class nifits.io.oifits.OI_TARGET[source]¶

Bases: NI_EXTENSION

OI_TARGET definition.

name = 'OI_TARGET'¶

classmethod from_scratch()[source]¶

Creates the OI_TARGET object with an empty table.

**Returns:: OI_TARGET: object with an empty table.

Use add_target() to finish the job.

add_target(target_id=0, target='MyTarget', raep0=0.0, decep0=0.0, equinox=0.0, ra_err=0.0, dec_err=0.0, sysvel=0.0, veltyp='', veldef='', pmra=0.0, pmdec=0.0, pmra_err=0.0, pmdec_err=0.0, parallax=0.0, para_err=0.0, spectyp='', category='')[source]¶

Use this method to add a row to the table of targets

Parameters:

target_id (param) – (default: 0)
target – (default: “MyTarget”)
raep0 – (default: 0.)
decep0 – (default: 0.)
equinox – (default: 0.)
ra_err – (default: 0.)
dec_err – (default: 0.)
sysvel – (default: 0.)
veltyp – (default: “”)
veldef – (default: “”)
pmra – (default: 0.)
pmdec – (default: 0.)
pmra_err – (default: 0.)
pmdec_err – (default: 0.)
parallax – (default: 0.)
para_err – (default: 0.)
spectyp – (default: “”)
category – (default: “”)

class nifits.io.oifits.NI_CATM[source]¶

Bases: NI_EXTENSION_CPX_ARRAY

Generic class for NIFITS array extensions.

The array is kept locally as complex valued, but it is stored to and loaded from a real-valued array with an extra first dimension of length 2 for (real, imaginary) parts.

property M¶

__doc__¶

name = 'NI_CATM'¶

class nifits.io.oifits.NI_IOUT[source]¶

Bases: NI_EXTENSION

NI_EXTENSION Generic class for NIFITS extensions

Inherited methods:

from_hdu: Creates the object from an astropy.io.fits.TableHDU object
to_hdu : Returns the TableHDU from itself.

Parameters:

data_table – [ArrayLike] The data to stored
header – [fits.Header] A fits header (optional)
unit – [astropy.units.Unit] Units of the data stored (mandatory of NI_IOUT, NI_KIOUT and NI_KCOV)

property iout¶

__doc__¶

name = 'NI_IOUT'¶

set_unit(new_unit, comment=None)[source]¶

class nifits.io.oifits.NI_KIOUT[source]¶

Bases: NI_EXTENSION

NI_EXTENSION Generic class for NIFITS extensions

Inherited methods:

from_hdu: Creates the object from an astropy.io.fits.TableHDU object
to_hdu : Returns the TableHDU from itself.

Parameters:

data_table – [ArrayLike] The data to stored
header – [fits.Header] A fits header (optional)
unit – [astropy.units.Unit] Units of the data stored (mandatory of NI_IOUT, NI_KIOUT and NI_KCOV)

property kiout¶

property shape¶

__doc__¶

unit: astropy.units.Unit¶

name = 'NI_KIOUT'¶

set_unit(new_unit, comment=None)[source]¶

class nifits.io.oifits.NI_KCOV[source]¶

Bases: NI_EXTENSION_ARRAY

Generic class for NIFITS array extensions

Parameters:

data_array – [ArrayLike] The data to stored
header – [fits.Header] A fits header (optional)
unit – [astropy.units.Unit] Units of the data stored (mandatory of NI_IOUT, NI_KIOUT and NI_KCOV)

property kcov¶

__doc__¶

unit: astropy.units.Unit¶

name = 'NI_KCOV'¶

set_unit(new_unit, comment=None)[source]¶

class nifits.io.oifits.NI_KMAT[source]¶

Bases: NI_EXTENSION_ARRAY

Generic class for NIFITS array extensions

Parameters:

data_array – [ArrayLike] The data to stored
header – [fits.Header] A fits header (optional)
unit – [astropy.units.Unit] Units of the data stored (mandatory of NI_IOUT, NI_KIOUT and NI_KCOV)

property K¶

__doc__¶

name = 'NI_KMAT'¶

class nifits.io.oifits.NI_DSAMP[source]¶

Bases: NI_EXTENSION_ARRAY

Generic class for NIFITS array extensions

Parameters:

data_array – [ArrayLike] The data to stored
header – [fits.Header] A fits header (optional)
unit – [astropy.units.Unit] Units of the data stored (mandatory of NI_IOUT, NI_KIOUT and NI_KCOV)

property D¶

__doc__¶

name = 'NI_DSAMP'¶

class nifits.io.oifits.NI_IOTAGS[source]¶

Bases: NI_EXTENSION

Contains information on the inputs and outputs.

property outbright¶: The flags of bright outputs

property outdark¶: The flags of dark outputs

property outbright¶: The flags of photometric outputs

property outpola¶: The polarization of outputs.

property inpola¶: The polarization of inputs.

data_table: Table¶

header: astropy.io.fits.Header¶

name = 'NI_MOD'¶

class nifits.io.oifits.NI_MOD[source]¶

Bases: NI_EXTENSION

Contains input modulation vector for the given observation. The format is a complex phasor representing the alteration applied by the instrument to the light at its inputs. Either an intended modulation, or an estimated instrumental error. the dimenstions are (n_ch, n_in)

The effects modeled in NI_MOD must cumulate with some that may be modeled in NI_CATM. It is recommended to include in CATM the static effects and in NI_MOD any affect that may vary throughout the observµng run.

\(n_a \times \lambda\)

information.

Item

format

unit

comment

APP_INDEX

int

NA

Indices of subaperture (starts at 0)

TARGET_ID

int

d

Index of target in OI_TARGET

TIME

float

s

Backwards compatibility

MJD

float

day

INT_TIME

float

s

Exposure time

MOD_PHAS

n_{wl},n_a float

Complex phasor of modulation for all collectors

APPXY

n_a,2 float

m

Projected location of subapertures in the plane orthogonal to the line of sight and oriented as ( \alpha, \delta)

ARRCOL

n_a float

\mathrm{m}^2

Collecting area of the subaperture

FOV_INDEX

n_a int

NA

The entry of the NI_FOV to use for this subaperture.

Item	format	unit	comment
`APP_INDEX`	`int`	NA	Indices of subaperture (starts at 0)
`TARGET_ID`	`int`	d	Index of target in `OI_TARGET`
`TIME`	`float`	s	Backwards compatibility
`MJD`	`float`	day
`INT_TIME`	`float`	s	Exposure time
`MOD_PHAS`	`n_{wl},n_a` `float`		Complex phasor of modulation for all collectors
`APPXY`	`n_a,2` `float`	m	Projected location of subapertures in the plane orthogonal to the line of sight and oriented as `( \alpha, \delta)`
`ARRCOL`	`n_a` `float`	`\mathrm{m}^2`	Collecting area of the subaperture
`FOV_INDEX`	`n_a` `int`	NA	The entry of the `NI_FOV` to use for this subaperture.

property n_series¶

property all_phasors¶

property appxy¶: Shape n_frames x n_a x 2

abstract property dateobs¶: Get the dateobs from the weighted mean of the observation time from each of the observation times given in the rows of NI_MOD table.

property arrcol¶: The collecting area of the telescopes

property int_time¶: Conveniently retrieve the integration time.

data_table: Table¶

header: astropy.io.fits.Header¶

name = 'NI_MOD'¶

nifits.io.oifits.create_basic_fov_data(D, offset, lamb, n)[source]¶: A convenience function to help define the FOV function and data model

class nifits.io.oifits.NI_FOV[source]¶

Bases: NI_EXTENSION

NI_EXTENSION Generic class for NIFITS extensions

Inherited methods:

from_hdu: Creates the object from an astropy.io.fits.TableHDU object
to_hdu : Returns the TableHDU from itself.

Parameters:

data_table – [ArrayLike] The data to stored
header – [fits.Header] A fits header (optional)
unit – [astropy.units.Unit] Units of the data stored (mandatory of NI_IOUT, NI_KIOUT and NI_KCOV)

__doc__¶

name = 'NI_FOV'¶

classmethod simple_from_header(header=None, lamb=None, n=0)[source]¶

Constructor for a simple NIFITS NI_FOV object with chromatic gaussian profile and no offset.

Parameters:: header – (astropy.io.fits.Header) Header containing the required information such as NIFITS FOV_TELDIAM and NIFITS FOV_TELDIAM_UNIT which are used to create the gaussian profiles of radius \(\lambda/D\)

get_fov_function(lamb: ArrayLike, n: int)[source]¶

Returns the function to get the chromatic phasor given by injection for a the index n of the time series

This method will move to the backend

Parameters:

lamb – The array of wavelength bins [m]
n – The index of the time series to compute for

nifits.io.oifits.TEST_BACKUP = True¶

nifits.io.oifits.NIFITS_EXTENSIONS¶

nifits.io.oifits.NIFITS_KEYWORDS = []¶

nifits.io.oifits.STATIC_EXTENSIONS = [True, True, True, True, False, False, False, False, False, True, True, False]¶

nifits.io.oifits.getclass(classname)[source]¶

nifits.io.oifits.H_PREFIX = 'HIERARCH NIFITS '¶

class nifits.io.oifits.nifits[source]¶

Bases: object

Class representation of the nifits object.

header: astropy.io.fits.Header¶

oi_array: OI_ARRAY¶

ni_catm: NI_CATM¶

ni_fov: NI_FOV¶

ni_kmat: NI_KMAT¶

oi_wavelength: OI_WAVELENGTH¶

oi_target: OI_TARGET¶

ni_mod: NI_MOD¶

ni_iout: NI_IOUT¶

ni_kiout: NI_KIOUT¶

ni_kcov: NI_KCOV¶

ni_dsamp: NI_DSAMP¶

ni_oswavelength: NI_OSWAVELENGTH¶

ni_iotags: NI_IOTAGS¶

classmethod from_nifits(filename: str)[source]¶: Create the nifits object from the HDU extension of an opened fits file.

to_nifits(filename: str = '', static_only: bool = False, dynamic_only: bool = False, static_hash: str = '', writefile: bool = True, overwrite: bool = False)[source]¶

Write the extension objects to a nifits file.

Parameters:

static_only – (bool) only save the extensions corresponding to static parameters of the model (NI_CATM and NI_FOV). Default: False
dynamic_only – (bool) only save the dynamic extensions. If true, the hash of the static file should be passed as static_hash. Defaultult: False
static_hash – (str) The hash of the static file. Default: “”

check_unit_coherence()[source]¶

Check the coherence of the units of and prints the result

NI_IOUT, NI_KCOV, and NI_KIOUT if they exist.

Otherwise, does nothing.

nifits.io.oifits¶

Module Contents¶

Classes¶

Functions¶

Attributes¶

`nifits.io.oifits`¶