DecamTranslator

class astro_metadata_translator.DecamTranslator(header, filename=None)

Bases: astro_metadata_translator.FitsTranslator

Metadata translator for DECam standard headers.

Attributes Summary

name	Name of this translation class
supported_instrument	Supports the DECam instrument.
translators

Methods Summary

can_translate(header[, filename])	Indicate whether this translation class can translate the supplied header.
can_translate_with_options(header, options)	Helper method for can_translate allowing options.
cards_used()	Cards used during metadata extraction.
determine_translator(header[, filename])	Determine a translation class by examining the header
quantity_from_card(keywords, unit[, …])	Calculate a Astropy Quantity from a header card and a unit.
to_altaz_begin()
to_boresight_airmass()	Airmass of the boresight of the telescope.
to_boresight_rotation_angle()	Angle of the instrument in boresight_rotation_coord frame.
to_boresight_rotation_coord()	Coordinate frame of the instrument rotation angle (options: sky, unknown).
to_dark_time()	Duration of the exposure with shutter closed (seconds).
to_datetime_begin()	Calculate start time of observation.
to_datetime_end()
to_detector_exposure_id()
to_detector_group()	Collection name of which this detector is a part.
to_detector_name()	Name of the detector within the instrument (might not be unique).
to_detector_num()	Unique (for instrument) integer identifier for the sensor.
to_detector_serial()	Serial number/string associated with this detector.
to_exposure_id()	Calculate exposure ID solely for science observations.
to_exposure_time()	Duration of the exposure with shutter open (seconds).
to_instrument()	The instrument used to observe the exposure.
to_location()	Calculate the observatory location.
to_object()	Object of interest or field name.
to_observation_id()	Label uniquely identifying this observation (can be related to ‘exposure_id’).
to_observation_type()	Calculate the observation type.
to_physical_filter()	Calculate physical filter.
to_pressure()	Atmospheric pressure outside the dome.
to_relative_humidity()	Relative humidity outside the dome.
to_science_program()	Observing program (survey or proposal) identifier.
to_telescope()	Full name of the telescope.
to_temperature()	Temperature outside the dome.
to_tracking_radec()
to_visit_id()
validate_value(value, default[, minimum, …])	Validate the supplied value, returning a new value if out of range

Attributes Documentation

name = 'DECam'

Name of this translation class

supported_instrument = 'DECam'

Supports the DECam instrument.

translators = {'DECam': <class 'astro_metadata_translator.translators.decam.DecamTranslator'>, 'HSC': <class 'astro_metadata_translator.translators.hsc.HscTranslator'>, 'MegaPrime': <class 'astro_metadata_translator.translators.megaprime.MegaPrimeTranslator'>, 'SuprimeCam': <class 'astro_metadata_translator.translators.suprimecam.SuprimeCamTranslator'>}

Methods Documentation

classmethod can_translate(header, filename=None)

Indicate whether this translation class can translate the supplied header.

Checks the INSTRUME and FILTER headers.

Parameters:

header : dict-like

Header to convert to standardized form.

filename : str, optional

Name of file being translated.

Returns:

can : bool

True if the header is recognized by this class. False otherwise.

classmethod can_translate_with_options(header, options, filename=None)

Helper method for can_translate allowing options.

Parameters:

header : dict-like

Header to convert to standardized form.

options : dict

Headers to try to determine whether this header can be translated by this class. If a card is found it will be compared with the expected value and will return that comparison. Each card will be tried in turn until one is found.

filename : str, optional

Name of file being translated.

Returns:

can : bool

True if the header is recognized by this class. False otherwise.

Notes

Intended to be used from within can_translate implementations for specific translators. Is not intended to be called directly from determine_translator.

cards_used()

Cards used during metadata extraction.

Returns:

used : frozenset of str

Cards used when extracting metadata.

classmethod determine_translator(header, filename=None)

Determine a translation class by examining the header

Parameters:

header : dict-like

Representation of a header.

filename : str, optional

Name of file being translated.

Returns:

translator : MetadataTranslator

Translation class that knows how to extract metadata from the supplied header.

Raises:

ValueError

None of the registered translation classes understood the supplied header.

quantity_from_card(keywords, unit, default=None, minimum=None, maximum=None, checker=None)

Calculate a Astropy Quantity from a header card and a unit.

Parameters:

keywords : str or list of str

Keyword to use from header. If a list each keyword will be tried in turn until one matches.

unit : astropy.units.UnitBase

Unit of the item in the header.

default : float, optional

Default value to use if the header value is invalid. Assumed to be in the same units as the value expected in the header. If None, no default value is used.

minimum : float, optional

Minimum possible valid value, optional. If the calculated value is below this value, the default value will be used.

maximum : float, optional

Maximum possible valid value, optional. If the calculated value is above this value, the default value will be used.

checker : function, optional

Callback function to be used by the translator method in case the keyword is not present. Function will be executed as if it is a method of the translator class. Running without raising an exception will allow the default to be used. Should usually raise KeyError.

Returns:

q : astropy.units.Quantity

Quantity representing the header value.

Raises:

KeyError

The supplied header key is not present.

to_altaz_begin()

to_boresight_airmass()

Airmass of the boresight of the telescope.

Returns:

translation : float

Translated value derived from the header.

to_boresight_rotation_angle()

Angle of the instrument in boresight_rotation_coord frame.

Returns:

translation : astropy.coordinates.Angle

Translated property.

to_boresight_rotation_coord()

Coordinate frame of the instrument rotation angle (options: sky, unknown).

Returns:

translation : str

Translated property.

to_dark_time()

Duration of the exposure with shutter closed (seconds).

Returns:

translation : astropy.units.Quantity

Translated value derived from the header.

to_datetime_begin()

Calculate start time of observation.

Uses FITS standard DATE-OBS and TIMESYS headers.

Returns:

start_time : astropy.time.Time

Time corresponding to the start of the observation.

to_datetime_end()

to_detector_exposure_id()

to_detector_group()

Collection name of which this detector is a part. Can be None if there are no detector groupings.

Returns:

translation : str

Translated property.

to_detector_name()

Name of the detector within the instrument (might not be unique).

Returns:

translation : str

Translated value derived from the header.

to_detector_num()

Unique (for instrument) integer identifier for the sensor.

Returns:

translation : int

Translated value derived from the header.

to_detector_serial()

Serial number/string associated with this detector.

Returns:

translation : str

Translated value derived from the header.

to_exposure_id()

Calculate exposure ID solely for science observations.

Returns:

id : int

ID of exposure.

to_exposure_time()

Duration of the exposure with shutter open (seconds).

Returns:

translation : astropy.units.Quantity

Translated value derived from the header.

to_instrument()

The instrument used to observe the exposure.

Returns:

translation : str

Translated value derived from the header.

to_location()

Calculate the observatory location.

Returns:

location : astropy.coordinates.EarthLocation

An object representing the location of the telescope.

to_object()

Object of interest or field name.

Returns:

translation : str

Translated value derived from the header.

to_observation_id()

Label uniquely identifying this observation (can be related to ‘exposure_id’).

Returns:

translation : str

Translated value derived from the header.

to_observation_type()

Calculate the observation type.

Returns:

typ : str

Observation type. Normalized to standard set.

to_physical_filter()

Calculate physical filter.

Return None if the keyword FILTER does not exist in the header, which can happen for some valid Community Pipeline products.

Returns:

filter : str

The full filter name.

to_pressure()

Atmospheric pressure outside the dome.

Returns:

translation : astropy.units.Quantity

Translated value derived from the header.

to_relative_humidity()

Relative humidity outside the dome.

Returns:

translation : float

Translated value derived from the header.

to_science_program()

Observing program (survey or proposal) identifier.

Returns:

translation : str

Translated value derived from the header.

to_telescope()

Full name of the telescope.

Returns:

translation : str

Translated value derived from the header.

to_temperature()

Temperature outside the dome.

Returns:

translation : astropy.units.Quantity

Translated value derived from the header.

to_tracking_radec()

to_visit_id()

static validate_value(value, default, minimum=None, maximum=None)

Validate the supplied value, returning a new value if out of range

Parameters:

value : float

Value to be validated.

default : float

Default value to use if supplied value is invalid or out of range. Assumed to be in the same units as the value expected in the header.

minimum : float

Minimum possible valid value, optional. If the calculated value is below this value, the default value will be used.

maximum : float

Maximum possible valid value, optional. If the calculated value is above this value, the default value will be used.

Returns:

value : float

Either the supplied value, or a default value.