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# This file is currently part of obs_lsst but is written to allow it 

# to be migrated to the astro_metadata_translator package at a later date. 

# 

# This product includes software developed by the LSST Project 

# (http://www.lsst.org). 

# See the LICENSE file in this directory for details of code ownership. 

# 

# Use of this source code is governed by a 3-clause BSD-style 

# license that can be found in the LICENSE file. 

 

"""Metadata translation code for LSST UCDavis Test Stand headers""" 

 

__all__ = ("LsstUCDCamTranslator", ) 

 

import logging 

import re 

import os.path 

 

import astropy.units as u 

from astropy.time import Time 

 

from astro_metadata_translator import cache_translation, StubTranslator 

 

from .lsst import compute_detector_exposure_id_generic 

 

log = logging.getLogger(__name__) 

 

# There is only one detector name used 

_DETECTOR_NAME = "S00" 

 

 

class LsstUCDCamTranslator(StubTranslator): 

"""Metadata translator for LSST UC Davis test camera data. 

 

This instrument is a test system for individual LSST CCDs. 

To fit this instrument into the standard naming convention for LSST 

instruments we use a fixed detector name (S00) and assign a different 

raft name to each detector. The detector number changes for each CCD. 

""" 

 

name = "LSST-UCDCam" 

"""Name of this translation class""" 

 

_const_map = { 

# TS8 is not attached to a telescope so many translations are null. 

"telescope": "LSST", 

"location": None, 

"boresight_rotation_coord": None, 

"boresight_rotation_angle": None, 

"boresight_airmass": None, 

"tracking_radec": None, 

"altaz_begin": None, 

"object": "UNKNOWN", 

"relative_humidity": None, 

"temperature": None, 

"pressure": None, 

"detector_name": _DETECTOR_NAME, 

} 

 

_trivial_map = { 

"exposure_time": ("EXPTIME", dict(unit=u.s)), 

} 

 

DETECTOR_NAME = _DETECTOR_NAME 

"""Fixed name of single sensor in raft.""" 

 

_detector_map = { 

"E2V-CCD250-112-04": (0, "R00"), 

"ITL-3800C-029": (1, "R01"), 

"ITL-3800C-002": (2, "R02"), 

} 

"""Map detector serial to raft and detector number. Eventually the 

detector number will come out of the policy camera definition.""" 

 

@classmethod 

def can_translate(cls, header, filename=None): 

"""Indicate whether this translation class can translate the 

supplied 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. 

""" 

# Check 3 headers that all have to match 

for k, v in (("ORIGIN", "UCDAVIS"), ("INSTRUME", "SAO"), ("TSTAND", "LSST_OPTICAL_SIMULATOR")): 

if k not in header: 

return False 

if header[k] != v: 

return False 

return True 

 

@classmethod 

def compute_detector_num_from_name(cls, detector_group, detector_name): 

"""Helper method to return the detector number from the name. 

 

Parameters 

---------- 

detector_group : `str` 

Detector group name. This is generally the raft name. 

detector_name : `str` 

Detector name. Checked to ensure it is the expected name. 

 

Returns 

------- 

num : `int` 

Detector number. 

 

Raises 

------ 

ValueError 

The supplied name is not known. 

""" 

if detector_name != cls.DETECTOR_NAME: 

raise ValueError(f"Detector {detector_name} is not known to UCDCam") 

for num, group in cls._detector_map.values(): 

if group == detector_group: 

return num 

raise ValueError(f"Detector {detector_group}_{detector_name} is not known to UCDCam") 

 

@classmethod 

def compute_detector_group_from_num(cls, detector_num): 

"""Helper method to return the detector group from the number. 

 

Parameters 

---------- 

detector_num : `int` 

Detector number. 

 

Returns 

------- 

group : `str` 

Detector group. 

 

Raises 

------ 

ValueError 

The supplied number is not known. 

""" 

for num, group in cls._detector_map.values(): 

if num == detector_num: 

return group 

raise ValueError(f"Detector {detector_num} is not known for UCDCam") 

 

@staticmethod 

def 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. 

""" 

return compute_detector_exposure_id_generic(exposure_id, detector_num, max_num=3, 

mode="concat") 

 

@staticmethod 

def compute_exposure_id(dateobs, seqnum=0): 

"""Helper method to calculate the exposure_id. 

 

Parameters 

---------- 

dateobs : `str` 

Date of observation in FITS ISO format. 

seqnum : `int`, unused 

Sequence number. Ignored. 

 

Returns 

------- 

exposure_id : `int` 

Exposure ID. 

""" 

# Use 1 second resolution 

exposure_id = re.sub(r"\D", "", dateobs[:19]) 

return int(exposure_id) 

 

@cache_translation 

def to_instrument(self): 

"""Calculate the instrument name. 

 

Returns 

------- 

instrume : `str` 

Name of the test stand. We do not distinguish between ITL and 

E2V. 

""" 

return self.name 

 

@cache_translation 

def to_datetime_begin(self): 

# Docstring will be inherited. Property defined in properties.py 

self._used_these_cards("MJD") 

mjd = float(self._header["MJD"]) # Header uses a FITS string 

return Time(mjd, scale="utc", format="mjd") 

 

@cache_translation 

def to_datetime_end(self): 

# Docstring will be inherited. Property defined in properties.py 

return self.to_datetime_begin() + self.to_exposure_time() 

 

@cache_translation 

def to_detector_num(self): 

"""Determine the number associated with this detector. 

 

Returns 

------- 

num : `int` 

The number of the detector. Each CCD gets a different number. 

""" 

serial = self.to_detector_serial() 

return self._detector_map[serial][0] 

 

@cache_translation 

def to_detector_group(self): 

"""Determine the pseudo raft name associated with this detector. 

 

Returns 

------- 

raft : `str` 

The name of the raft. The raft is derived from the serial number 

of the detector. 

""" 

serial = self.to_detector_serial() 

return self._detector_map[serial][1] 

 

@cache_translation 

def to_dark_time(self): 

"""Calculate the dark time. 

 

If a DARKTIME header is not found, the value is assumed to be 

identical to the exposure time. 

 

Returns 

------- 

dark : `astropy.units.Quantity` 

The dark time in seconds. 

""" 

if "DARKTIME" in self._header: 

darktime = self._header("DARKTIME")*u.s 

else: 

log.warning("Unable to determine dark time. Setting from exposure time.") 

darktime = self.to_exposure_time() 

return darktime 

 

@cache_translation 

def to_detector_serial(self): 

"""Returns the serial number of the detector. 

 

Returns 

------- 

serial : `str` 

LSST assigned serial number. 

 

Notes 

----- 

This is the LSST assigned serial number (``LSST_NUM``), and not 

necessarily the manufacturer's serial number (``CCD_SERN``). 

""" 

serial = self._header["LSST_NUM"] 

self._used_these_cards("LSST_NUM") 

return serial 

 

@cache_translation 

def to_detector_exposure_id(self): 

# Docstring will be inherited. Property defined in properties.py 

exposure_id = self.to_exposure_id() 

num = self.to_detector_num() 

return self.compute_detector_exposure_id(exposure_id, num) 

 

@cache_translation 

def to_physical_filter(self): 

"""Return the filter name. 

 

Uses the FILTER header. 

 

Returns 

------- 

filter : `str` 

The filter name. Returns "NONE" if no filter can be determined. 

""" 

 

if "FILTER" in self._header: 

self._used_these_cards("FILTER") 

return self._header["FILTER"].lower() 

else: 

log.warning("FILTER key not found in header (assuming NONE)") 

return "NONE" 

 

def to_exposure_id(self): 

"""Generate a unique exposure ID number 

 

Note that SEQNUM is not unique for a given day 

so instead we convert the ISO date of observation directly to an 

integer. 

 

Returns 

------- 

exposure_id : `int` 

Unique exposure number. 

""" 

date = self.to_datetime_begin() 

return self.compute_exposure_id(date.isot) 

 

# For now assume that visit IDs and exposure IDs are identical 

to_visit_id = to_exposure_id 

 

@cache_translation 

def to_observation_id(self): 

# Docstring will be inherited. Property defined in properties.py 

filename = self._header["FILENAME"] 

self._used_these_cards("FILENAME") 

return os.path.splitext(os.path.basename(filename))[0] 

 

@cache_translation 

def to_observation_type(self): 

# Docstring will be inherited. Property defined in properties.py 

obstype = self._header["IMGTYPE"] 

self._used_these_cards("IMGTYPE") 

return obstype.lower() 

 

@cache_translation 

def to_science_program(self): 

"""Calculate the run number for this observation. 

 

There is no explicit run header, so instead treat each day 

as the run in YYYY-MM-DD format. 

 

Returns 

------- 

run : `str` 

YYYY-MM-DD string corresponding to the date of observation. 

""" 

# Get a copy so that we can edit the default formatting 

date = self.to_datetime_begin().copy() 

date.format = "iso" 

date.out_subfmt = "date" # YYYY-MM-DD format 

return str(date)