Coverage for python / astro_metadata_translator / translators / sdss.py: 40%
104 statements
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1# This file is part of astro_metadata_translator.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (http://www.lsst.org).
6# See the LICENSE file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# Use of this source code is governed by a 3-clause BSD-style
10# license that can be found in the LICENSE file.
12"""Metadata translation code for SDSS FITS headers."""
14from __future__ import annotations
16__all__ = ("SdssTranslator",)
18import posixpath
19from collections.abc import Mapping
20from typing import TYPE_CHECKING, Any
22import astropy.units as u
23from astropy.coordinates import AltAz, Angle, EarthLocation, UnknownSiteException
25from ..translator import CORRECTIONS_RESOURCE_ROOT, cache_translation
26from .fits import FitsTranslator
27from .helpers import tracking_from_degree_headers
29if TYPE_CHECKING:
30 import astropy.coordinates
31 import astropy.time
34# Hard-code APO location fallback.
35_APO_LOCATION = EarthLocation.from_geocentric(
36 -1463969.30185172, -5166673.34223433, 3434985.71204565, unit=u.m
37)
40class SdssTranslator(FitsTranslator):
41 """Metadata translator for SDSS standard headers.
42 NB: calibration data is not handled as calibration frames were
43 not available to me at time of writing.
44 """
46 name = "SDSS"
47 """Name of this translation class"""
49 supported_instrument = "Imager"
50 """Supports the SDSS imager instrument."""
52 default_resource_root = posixpath.join(CORRECTIONS_RESOURCE_ROOT, "SDSS")
53 """Default resource path root to use to locate header correction files."""
55 # SDSS has has a rotator, but in drift scan mode, the instrument
56 # angle on sky is set to +X=East, +Y=North which we define as a
57 # 0 degree rotation.
58 _const_map = {
59 "boresight_rotation_angle": Angle(0 * u.deg),
60 "boresight_rotation_coord": "sky",
61 "dark_time": 0.0 * u.s, # Drift scan implies no dark time
62 "instrument": "Imager on SDSS 2.5m", # We only ever ingest data from the imager
63 "telescope": "SDSS 2.5m", # Value of TELESCOP in header is ambiguous
64 "relative_humidity": None,
65 "temperature": None,
66 "pressure": None,
67 "detector_serial": "UNKNOWN",
68 }
70 _trivial_map = {
71 "exposure_time": ("EXPTIME", {"unit": u.s}),
72 "object": "OBJECT",
73 "physical_filter": "FILTER",
74 "exposure_id": "RUN",
75 "visit_id": "RUN",
76 "science_program": "OBJECT", # This is the closest I can think of to a useful program
77 "detector_name": "CCDLOC", # This is a numeric incoding of the "slot", i.e. filter+camcol
78 }
80 # Need a mapping from unique name to index. The order is arbitrary.
81 detector_name_id_map = {
82 "g1": 0,
83 "z1": 1,
84 "u1": 2,
85 "i1": 3,
86 "r1": 4,
87 "g2": 5,
88 "z2": 6,
89 "u2": 7,
90 "i2": 8,
91 "r2": 9,
92 "g3": 10,
93 "z3": 11,
94 "u3": 12,
95 "i3": 13,
96 "r3": 14,
97 "g4": 15,
98 "z4": 16,
99 "u4": 17,
100 "i4": 18,
101 "r4": 19,
102 "g5": 20,
103 "z5": 21,
104 "u5": 22,
105 "i5": 23,
106 "r5": 24,
107 "g6": 25,
108 "z6": 26,
109 "u6": 27,
110 "i6": 28,
111 "r6": 29,
112 }
114 @classmethod
115 def can_translate(cls, header: Mapping[str, Any], filename: str | None = None) -> bool:
116 """Indicate whether this translation class can translate the
117 supplied header.
119 Parameters
120 ----------
121 header : `dict`-like
122 Header to convert to standardized form.
123 filename : `str`, optional
124 Name of file being translated.
126 Returns
127 -------
128 can : `bool`
129 `True` if the header is recognized by this class. `False`
130 otherwise.
131 """
132 if (
133 cls.is_keyword_defined(header, "ORIGIN")
134 and cls.is_keyword_defined(header, "CCDMODE")
135 and cls.is_keyword_defined(header, "TELESCOP")
136 and "2.5m" in header["TELESCOP"]
137 and "SDSS" in header["ORIGIN"]
138 and "DRIFT" in header["CCDMODE"]
139 ):
140 return True
141 return False
143 @cache_translation
144 def to_detector_unique_name(self) -> str:
145 # Docstring will be inherited. Property defined in properties.py
146 if self.is_key_ok("CAMCOL"):
147 return self.to_physical_filter() + str(self._header["CAMCOL"])
148 else:
149 raise ValueError(f"{self._log_prefix}: CAMCOL key is not definded")
151 @cache_translation
152 def to_detector_num(self) -> int:
153 # Docstring will be inherited. Property defined in properties.py
154 return self.detector_name_id_map[self.to_detector_unique_name()]
156 @cache_translation
157 def to_observation_id(self) -> str:
158 """Calculate the observation ID.
160 Returns
161 -------
162 observation_id : `str`
163 A string uniquely describing the observation.
164 This incorporates the run, camcol, filter and frame.
165 """
166 return " ".join([str(self._header[el]) for el in ["RUN", "CAMCOL", "FILTER", "FRAME"]])
168 @cache_translation
169 def to_datetime_begin(self) -> astropy.time.Time:
170 # Docstring will be inherited. Property defined in properties.py
171 # We know it is UTC
172 value = self._from_fits_date_string(
173 self._header["DATE-OBS"], time_str=self._header["TAIHMS"], scale="tai"
174 )
175 self._used_these_cards("DATE-OBS", "TAIHMS")
176 return value
178 @cache_translation
179 def to_datetime_end(self) -> astropy.time.Time:
180 # Docstring will be inherited. Property defined in properties.py
181 return self.to_datetime_begin() + self.to_exposure_time()
183 @cache_translation
184 def to_location(self) -> EarthLocation:
185 """Calculate the observatory location.
187 Returns
188 -------
189 location : `astropy.coordinates.EarthLocation`
190 An object representing the location of the telescope.
191 """
192 # Look up the value since files do not have location.
193 # This might require a network look up if the cached database
194 # is not accessible. If it fails fall back to hard-coded location.
195 try:
196 value = EarthLocation.of_site("apo")
197 except UnknownSiteException:
198 value = _APO_LOCATION
200 return value
202 @cache_translation
203 def to_observation_type(self) -> str:
204 """Calculate the observation type.
206 Returns
207 -------
208 typ : `str`
209 Observation type. Normalized to standard set.
210 """
211 obstype_key = "FLAVOR"
212 if not self.is_key_ok(obstype_key):
213 return "none"
214 obstype = self._header[obstype_key].strip().lower()
215 self._used_these_cards(obstype_key)
216 return obstype
218 @cache_translation
219 def to_tracking_radec(self) -> astropy.coordinates.SkyCoord | None:
220 # Docstring will be inherited. Property defined in properties.py
221 radecsys = ("RADECSYS",)
222 radecpairs = (("RA", "DEC"),)
223 return tracking_from_degree_headers(self, radecsys, radecpairs, unit=u.deg)
225 @cache_translation
226 def to_altaz_begin(self) -> AltAz | None:
227 # Docstring will be inherited. Property defined in properties.py
228 try:
229 az = self._header["AZ"]
230 alt = self._header["ALT"]
231 # It appears SDSS defines azimuth as increasing
232 # from South through East. This translates to
233 # North through East
234 az = (-az + 180.0) % 360.0
235 altaz = AltAz(
236 az * u.deg, alt * u.deg, obstime=self.to_datetime_begin(), location=self.to_location()
237 )
238 self._used_these_cards("AZ", "ALT")
239 return altaz
240 except Exception as e:
241 if self.to_observation_type() != "science":
242 return None # Allow Alt/Az not to be set for calibrations
243 raise (e)
245 @cache_translation
246 def to_boresight_airmass(self) -> float | None:
247 # Docstring will be inherited. Property defined in properties.py
248 altaz = self.to_altaz_begin()
249 if altaz is not None:
250 return altaz.secz.value # This is an estimate
251 return None
253 @cache_translation
254 def to_detector_exposure_id(self) -> int | None:
255 # Docstring will be inherited. Property defined in properties.py
256 run = self.to_exposure_id()
257 filt = self.to_physical_filter()
258 try:
259 frame_field_map = {"r": 0, "i": 2, "u": 4, "z": 6, "g": 8}
260 camcol = self._header["CAMCOL"]
261 field = self._header["FRAME"] - frame_field_map[filt]
262 self._used_these_cards("CAMCOL", "FRAME")
263 except Exception as e:
264 if self.to_observation_type() != "science":
265 return None
266 raise (e)
267 filter_id_map = {"u": 0, "g": 1, "r": 2, "i": 3, "z": 4}
268 return ((int(run) * 10 + filter_id_map[filt]) * 10 + int(camcol)) * 10000 + int(field)
270 @cache_translation
271 def to_detector_group(self) -> str:
272 # Docstring will be inherited. Property defined in properties.py
273 if self.is_key_ok("CAMCOL"):
274 return str(self._header["CAMCOL"])
275 else:
276 raise ValueError(f"{self._log_prefix}: CAMCOL key is not definded")