LsstCamImSimTranslator

class lsst.obs.lsst.translators.LsstCamImSimTranslator(header, filename=None)

Bases: lsst.obs.lsst.translators.lsstsim.LsstSimTranslator

Metadata translation class for LSSTCam imSim headers

Attributes Summary

DETECTOR_MAX
cameraPolicyFile
default_resource_package
default_resource_root
default_search_path
detectorMapping
detectorSerials
name	Name of this translation class
supported_instrument
translators

Methods Summary

are_keys_ok(keywords)	Are the supplied keys all present and defined?
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.
compute_detector_exposure_id(exposure_id, …)	Compute the detector exposure ID from detector number and exposure ID.
compute_detector_info_from_serial(…)	Helper method to return the detector information from the serial.
compute_detector_num_from_name(…)	Helper method to return the detector number from the name.
compute_exposure_id(dayobs, seqnum[, controller])	Helper method to calculate the exposure_id.
defined_in_this_class(name)	Report if the specified class attribute is defined specifically in this class.
detector_mapping()	Returns the mapping of full name to detector ID and serial.
detector_serials()	Obtain the mapping of detector serial to detector group, name, and number.
determine_translatable_headers(filename[, …])	Given a file return all the headers usable for metadata translation.
determine_translator(header[, filename])	Determine a translation class by examining the header
fix_header(header, instrument, obsid[, filename])	Apply global fixes to a supplied header.
is_key_ok(keyword)	Return True if the value associated with the named keyword is present in this header and defined.
is_keyword_defined(header, keyword)	Return True if the value associated with the named keyword is present in the supplied header and defined.
is_on_sky()	Determine if this is an on-sky observation.
max_detector_exposure_id()	The maximum detector exposure ID expected to be generated by this instrument.
max_exposure_id()	The maximum exposure ID expected from this instrument.
quantity_from_card(keywords, unit[, …])	Calculate a Astropy Quantity from a header card and a unit.
resource_root()	Package resource to use to locate correction resources within an installed package.
search_paths()	Search paths to use for LSST data when looking for header correction files.
to_altaz_begin()
to_boresight_airmass()
to_boresight_rotation_angle()
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()
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 if there are detector groups).
to_detector_num()
to_detector_serial()	Serial number/string associated with this detector.
to_detector_unique_name()	Return a unique name for the detector.
to_exposure_group()	Calculate the exposure group string.
to_exposure_id()	Unique (with instrument) integer identifier for this observation.
to_exposure_time()	Duration of the exposure with shutter open (seconds).
to_instrument()	The instrument used to observe the exposure.
to_location()
to_object()	Object of interest or field name.
to_observation_counter()	Counter of this observation.
to_observation_id()	Label uniquely identifying this observation (can be related to ‘exposure_id’).
to_observation_reason()
to_observation_type()
to_observing_day()	Return the day of observation as YYYYMMDD integer.
to_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()
to_temperature()	Temperature outside the dome.
to_tracking_radec()
to_visit_id()	ID of the Visit this Exposure is associated with.
translator_version()	Return the version string for this translator class.
validate_value(value, default[, minimum, …])	Validate the supplied value, returning a new value if out of range

Attributes Documentation

DETECTOR_MAX = 1000

cameraPolicyFile = 'policy/imsim.yaml'

default_resource_package = 'astro_metadata_translator'

default_resource_root = None

default_search_path = None

detectorMapping = None

detectorSerials = None

name = 'LSSTCam-imSim'

Name of this translation class

supported_instrument = None

translators = {'DECam': <class 'astro_metadata_translator.translators.decam.DecamTranslator'>, 'HSC': <class 'astro_metadata_translator.translators.hsc.HscTranslator'>, 'LSST-TS3': <class 'lsst.obs.lsst.translators.ts3.LsstTS3Translator'>, 'LSST-TS8': <class 'lsst.obs.lsst.translators.ts8.LsstTS8Translator'>, 'LSST-UCDCam': <class 'lsst.obs.lsst.translators.lsst_ucdcam.LsstUCDCamTranslator'>, 'LSSTCam': <class 'lsst.obs.lsst.translators.lsstCam.LsstCamTranslator'>, 'LSSTCam-PhoSim': <class 'lsst.obs.lsst.translators.phosim.LsstCamPhoSimTranslator'>, 'LSSTCam-imSim': <class 'lsst.obs.lsst.translators.imsim.LsstCamImSimTranslator'>, 'LSSTComCam': <class 'lsst.obs.lsst.translators.comCam.LsstComCamTranslator'>, 'LSST_LATISS': <class 'lsst.obs.lsst.translators.latiss.LatissTranslator'>, 'MegaPrime': <class 'astro_metadata_translator.translators.megaprime.MegaPrimeTranslator'>, 'SDSS': <class 'astro_metadata_translator.translators.sdss.SdssTranslator'>, 'SuprimeCam': <class 'astro_metadata_translator.translators.suprimecam.SuprimeCamTranslator'>}

Methods Documentation

are_keys_ok(keywords)

Are the supplied keys all present and defined?

Parameters:

keywords : iterable of str

Keywords to test.

Returns:

all_ok : bool

True if all supplied keys are present and defined.

classmethod can_translate(header, filename=None)

Indicate whether this translation class can translate the supplied header.

There is no INSTRUME header in ImSim data. Instead we use the TESTTYPE header.

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 compute_detector_exposure_id(exposure_id, detector_num)

Compute the detector exposure ID from detector number and exposure ID.

This is a helper method to allow code working outside the translator infrastructure to use the same algorithm.

Parameters:

exposure_id : int

Unique exposure ID.

detector_num : int

Detector number.

Returns:

detector_exposure_id : int

The calculated ID.

classmethod compute_detector_info_from_serial(detector_serial)

Helper method to return the detector information from the serial.

Parameters:

detector_serial : str

Detector serial ID.

Returns:

info : tuple of (str, str, int)

Detector group, name, and number.

classmethod compute_detector_num_from_name(detector_group, detector_name)

Helper method to return the detector number from the name.

Parameters:

detector_group : str

Name of the detector grouping. This is generally the raft name.

detector_name : str

Detector name.

Returns:

num : int

Detector number.

static compute_exposure_id(dayobs, seqnum, controller=None)

Helper method to calculate the exposure_id.

Parameters:

dayobs : str

Day of observation in either YYYYMMDD or YYYY-MM-DD format. If the string looks like ISO format it will be truncated before the T before being handled.

seqnum : int or str

Sequence number.

controller : str, optional

Controller to use. If this is “O”, no change is made to the exposure ID. If it is “C” a 1000 is added to the year component of the exposure ID. If it is “H” a 2000 is added to the year component. None indicates that the controller is not relevant to the exposure ID calculation (generally this is the case for test stand data).

Returns:

exposure_id : int

Exposure ID in form YYYYMMDDnnnnn form.

classmethod defined_in_this_class(name)

Report if the specified class attribute is defined specifically in this class.

Parameters:

name : str

Name of the attribute to test.

Returns:

in_class : bool

True if there is a attribute of that name defined in this specific subclass. False if the method is not defined in this specific subclass but is defined in a parent class. Returns None if the attribute is not defined anywhere in the class hierarchy (which can happen if translators have typos in their mapping tables).

Notes

Retrieves the attribute associated with the given name. Then looks in all the parent classes to determine whether that attribute comes from a parent class or from the current class. Attributes are compared using id().

classmethod detector_mapping()

Returns the mapping of full name to detector ID and serial.

Returns:

mapping : dict of str:tuple

Returns the mapping of full detector name (group+detector) to detector number and serial.

Raises:

ValueError

Raised if no camera policy file has been registered with this translation class.

Notes

Will construct the mapping if none has previously been constructed.

classmethod detector_serials()

Obtain the mapping of detector serial to detector group, name, and number.

Returns:

info : dict of tuple of (str, str, int)

A dict with the serial numbers as keys and values of detector group, name, and number.

classmethod determine_translatable_headers(filename, primary=None)

Given a file return all the headers usable for metadata translation.

This method can optionally be given a header from the file. This header will generally be the primary header or a merge of the first two headers.

In the base class implementation it is assumed that this supplied header is the only useful header for metadata translation and it will be returned unchanged if given. This can avoid unnecesarily re-opening the file and re-reading the header when the content is already known.

If no header is supplied, a header will be read from the supplied file using read_basic_metadata_from_file, allowing it to merge the primary and secondary header of a multi-extension FITS file. Subclasses can read the header from the data file using whatever technique is best for that instrument.

Subclasses can return multiple headers and ignore the externally supplied header. They can also merge it with another header and return a new derived header if that is required by the particular data file. There is no requirement for the supplied header to be used.

Parameters:

filename : str

Path to a file in a format understood by this translator.

primary : dict-like, optional

The primary header obtained by the caller. This is sometimes already known, for example if a system is trying to bootstrap without already knowing what data is in the file. For many instruments where the primary header is the only relevant header, the primary header will be returned with no further action.

Yields:

headers : iterator of dict-like

A header usable for metadata translation. For this base implementation it will be either the supplied primary header or a header read from the file. This implementation will only ever yield a single header.

Notes

Each translator class can have code specifically tailored to its own file format. It is important not to call this method with an incorrect translator class. The normal paradigm is for the caller to have read the first header and then called determine_translator() on the result to work out which translator class to then call to obtain the real headers to be used for translation.

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.

classmethod fix_header(header, instrument, obsid, filename=None)

Apply global fixes to a supplied header.

Parameters:

header : dict

The header to correct. Correction is in place.

instrument : str

The name of the instrument.

obsid : str

Unique observation identifier associated with this header. Will always be provided.

filename : str, optional

Filename associated with this header. May not be set since headers can be fixed independently of any filename being known.

Returns:

modified : bool

True if a correction was applied.

Notes

This method is intended to support major discrepancies in headers such as:

• Periods of time where headers are known to be incorrect in some way that can be fixed either by deriving the correct value from the existing value or understanding the that correction is static for the given time. This requires that the date header is known.
• The presence of a certain value is always wrong and should be corrected with a new static value regardless of date.

It is assumed that one off problems with headers have been applied before this method is called using the per-obsid correction system.

Usually called from astro_metadata_translator.fix_header.

For log messages, do not assume that the filename will be present. Always write log messages to fall back on using the obsid if filename is None.

is_key_ok(keyword)

Return True if the value associated with the named keyword is present in this header and defined.

Parameters:

keyword : str

Keyword to check against header.

Returns:

is_ok : bool

True if the header is present and not-None. False otherwise.

static is_keyword_defined(header, keyword)

Return True if the value associated with the named keyword is present in the supplied header and defined.

Parameters:

header : dict-lik

Header to use as reference.

keyword : str

Keyword to check against header.

Returns:

is_defined : bool

True if the header is present and not-None. False otherwise.

is_on_sky()

Determine if this is an on-sky observation.

Returns:

is_on_sky : bool

Returns True if this is a observation on sky on the summit.

classmethod max_detector_exposure_id()

The maximum detector exposure ID expected to be generated by this instrument.

Returns:

max_id : int

The maximum value.

classmethod max_exposure_id()

The maximum exposure ID expected from this instrument.

Returns:

max_exposure_id : int

The maximum value.

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.

resource_root()

Package resource to use to locate correction resources within an installed package.

Returns:

resource_package : str

Package resource name. None if no package resource are to be used.

resource_root : str

The name of the resource root. None if no package resources are to be used.

search_paths()

Search paths to use for LSST data when looking for header correction files.

Returns:

path : list

List with a single element containing the full path to the corrections directory within the obs_lsst package.

to_altaz_begin()

to_boresight_airmass()

to_boresight_rotation_angle()

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()

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 value derived from the header.

to_detector_name()

Name of the detector within the instrument (might not be unique if there are detector groups).

Returns:

translation : str

Translated value derived from the header.

to_detector_num()

to_detector_serial()

Serial number/string associated with this detector.

Returns:

translation : str

Translated value derived from the header.

to_detector_unique_name()

Return a unique name for the detector.

Base class implementation attempts to combine detector_name with detector_group. Group is only used if not None.

Can be over-ridden by specialist translator class.

Returns:

name : str

detector_group``_``detector_name if detector_group is defined, else the detector_name is assumed to be unique. If neither return a valid value an exception is raised.

Raises:

NotImplementedError

Raised if neither detector_name nor detector_group is defined.

to_exposure_group()

Calculate the exposure group string.

For LSSTCam and LATISS this is read from the GROUPID header. If that header is missing the exposure_id is returned instead as a string.

to_exposure_id()

Unique (with instrument) integer identifier for this observation.

Returns:

translation : int

Translated value derived from the header.

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 property.

to_location()

to_object()

Object of interest or field name.

Returns:

translation : str

Translated property.

to_observation_counter()

Counter of this observation. Can be counter within observing_day or a global counter. Likely to be observatory specific.

Returns:

translation : int

Translated property.

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_reason()

to_observation_type()

to_observing_day()

Return the day of observation as YYYYMMDD integer.

For LSSTCam and other compliant instruments this is the value of the DAYOBS header.

Returns:

obs_day : int

The day of observation.

to_physical_filter()

to_pressure()

Atmospheric pressure outside the dome.

Returns:

translation : astropy.units.Quantity

Translated property.

to_relative_humidity()

Relative humidity outside the dome.

Returns:

translation : float

Translated property.

to_science_program()

Observing program (survey or proposal) identifier.

Returns:

translation : str

Translated value derived from the header.

to_telescope()

to_temperature()

Temperature outside the dome.

Returns:

translation : astropy.units.Quantity

Translated property.

to_tracking_radec()

to_visit_id()

ID of the Visit this Exposure is associated with.

Science observations should essentially always be associated with a visit, but calibration observations may not be.

Returns:

translation : int

Translated value derived from the header.

classmethod translator_version()

Return the version string for this translator class.

Returns:

version : str

String identifying the version of this translator.

Notes

Assumes that the version is available from the __version__ variable in the parent module. If this is not the case a translator should subclass this method.

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.