/
lightcurvefile.py
400 lines (343 loc) · 15.7 KB
/
lightcurvefile.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
"""Defines LightCurveFile classes, i.e. files that contain LightCurves."""
from __future__ import division, print_function
import os
import logging
import numpy as np
import matplotlib as mpl
from matplotlib import pyplot as plt
from astropy.io import fits as pyfits
from .utils import (bkjd_to_astropy_time, KeplerQualityFlags, TessQualityFlags)
from .mast import download_kepler_products
__all__ = ['KeplerLightCurveFile', 'TessLightCurveFile']
log = logging.getLogger(__name__)
class LightCurveFile(object):
"""Defines a generic class to handle light curve files.
Parameters
----------
path : str
Local path or remote url of a lightcurve FITS file.
kwargs : dict
Keyword arguments to be passed to astropy.io.fits.open.
"""
def __init__(self, path, **kwargs):
self.path = path
self.hdu = pyfits.open(self.path, **kwargs)
def header(self, ext=0):
"""Header of the object at extension `ext`"""
return self.hdu[ext].header
@property
def time(self):
"""Time measurements"""
return self.hdu[1].data['TIME'][self.quality_mask]
@property
def ra(self):
"""Right Ascension of the target."""
return self.hdu[0].header['RA_OBJ']
@property
def dec(self):
"""Declination of the target."""
return self.hdu[0].header['DEC_OBJ']
@property
def SAP_FLUX(self):
"""Returns a LightCurve object for SAP_FLUX"""
return self.get_lightcurve('SAP_FLUX')
@property
def PDCSAP_FLUX(self):
"""Returns a LightCurve object for PDCSAP_FLUX"""
return self.get_lightcurve('PDCSAP_FLUX')
@property
def cadenceno(self):
"""Cadence number"""
return self.hdu[1].data['CADENCENO'][self.quality_mask]
@classmethod
def from_fits(cls, path_or_url, **kwargs):
"""Open a Light Curve File using the path or url of a FITS file.
This is identical to opening a Light Curve File via the constructor.
This method was added because many tutorials use the `from_archive`
method, therefore users may expect a `from_fits` equivalent.
Parameters
----------
path_or_url : str
Path or URL of a FITS file.
**kwargs : dict
Keyword arguments that will be passed to the constructor.
Returns
-------
tpf : LightCurveFile object
The loaded light curve file.
"""
return cls(path_or_url, **kwargs)
def _flux_types(self):
"""Returns a list of available flux types for this light curve file"""
types = [n for n in self.hdu[1].data.columns.names if 'FLUX' in n]
types = [n for n in types if not ('ERR' in n)]
return types
def plot(self, flux_types=None, style='fast', **kwargs):
"""Plot all the light curves contained in this light curve file.
Parameters
----------
flux_types : str or list of str
List of flux types to plot. Default is to plot all available.
(For Kepler the default fluxes are 'SAP_FLUX' and 'PDCSAP_FLUX'.
style : str
matplotlib.pyplot.style.context, default is 'fast'
kwargs : dict
Dictionary of keyword arguments to be passed to
`KeplerLightCurve.plot()`.
"""
if (style == "fast") and ("fast" not in mpl.style.available):
style = "default"
with plt.style.context(style):
if not ('ax' in kwargs):
fig, ax = plt.subplots(1)
kwargs['ax'] = ax
if flux_types is None:
flux_types = self._flux_types()
if isinstance(flux_types, str):
flux_types = [flux_types]
for idx, ft in enumerate(flux_types):
lc = self.get_lightcurve(ft)
kwargs['color'] = np.asarray(mpl.rcParams['axes.prop_cycle'])[idx]['color']
lc.plot(label=ft, **kwargs)
class KeplerLightCurveFile(LightCurveFile):
"""Defines a class for a given light curve FITS file from NASA's Kepler and
K2 missions.
Parameters
----------
path : str
Local path or remote url of a FITS file in Kepler's lightcurve format.
quality_bitmask : str or int
Bitmask (integer) which identifies the quality flag bitmask that should
be used to mask out bad cadences. If a string is passed, it has the
following meaning:
* "none": no cadences will be ignored (`quality_bitmask=0`).
* "default": cadences with severe quality issues will be ignored
(`quality_bitmask=1130799`).
* "hard": more conservative choice of flags to ignore
(`quality_bitmask=1664431`). This is known to remove good data.
* "hardest": removes all data that has been flagged
(`quality_bitmask=2096639`). This mask is not recommended.
See the :class:`KeplerQualityFlags` class for details on the bitmasks.
kwargs : dict
Keyword arguments to be passed to astropy.io.fits.open.
"""
def __init__(self, path, quality_bitmask='default', **kwargs):
super(KeplerLightCurveFile, self).__init__(path, **kwargs)
self.quality_bitmask = quality_bitmask
self.quality_mask = KeplerQualityFlags.create_quality_mask(
quality_array=self.hdu[1].data['SAP_QUALITY'],
bitmask=quality_bitmask)
try:
self.targetid = self.header()['KEPLERID']
except KeyError:
self.targetid = None
@staticmethod
def from_archive(target, cadence='long', quarter=None, month=None,
campaign=None, radius=1., targetlimit=1,
quality_bitmask="default", **kwargs):
"""Fetches a LightCurveFile (or list thereof) from the data archive at MAST.
If a target was observed across multiple quarters or campaigns, a
list of `LightCurveFile` objects will only be returned if the string
'all' is passed to `quarter` or `campaign`. Alternatively, a list of
numbers can be pased to these arguments.
An `ArchiveError` will be raised if no (unique) LightCurveFile
can be found.
If `targetlimit` is set to more than one (or None) then will return a list
of `KeplerLightCurveFile`. Will only return hits within the specified radius.
Parameters
----------
target : str or int
KIC/EPIC ID or object name.
cadence : str
'long' or 'short'.
quarter, campaign : int, list of ints, or 'all'
Kepler Quarter or K2 Campaign number.
month : 1, 2, 3, list of int, or 'all'
For Kepler's prime mission, there are three short-cadence
LightCurveFile objects for each quarter, each covering one month.
Hence, if cadence='short' you need to specify month=1, 2, or 3.
radius : float
Search radius in arcseconds. Default is 1 arcsecond.
targetlimit : None or int
If multiple targets are present within `radius`, limit the number
of returned LightCurveFile objects to `targetlimit`.
If `None`, no limit is applied.
quality_bitmask : str or int
Bitmask (integer) which identifies the quality flag bitmask that should
be used to mask out bad cadences. If a string is passed, it has the
following meaning:
* "none": no cadences will be ignored (`quality_bitmask=0`).
* "default": cadences with severe quality issues will be ignored
(`quality_bitmask=1130799`).
* "hard": more conservative choice of flags to ignore
(`quality_bitmask=1664431`). This is known to remove good data.
* "hardest": removes all data that has been flagged
(`quality_bitmask=2096639`). This mask is not recommended.
See the :class:`KeplerQualityFlags` class for details on the bitmasks.
kwargs : dict
Keywords arguments passed to `KeplerLightCurveFile`.
Returns
-------
lcf : KeplerLightCurveFile object or list of KeplerLightCurveFile objects
"""
# Be tolerant if a direct path or url is passed to this function by accident
if os.path.exists(str(target)) or str(target).startswith('http'):
log.warning('Warning: from_archive() is not intended to accept a '
'direct path, use KeplerLightCurveFile(path) instead.')
path = [target]
else:
path = download_kepler_products(
target=target, filetype='Lightcurve', cadence=cadence,
quarter=quarter, campaign=campaign, month=month,
radius=radius, targetlimit=targetlimit)
if len(path) == 1:
return KeplerLightCurveFile(path[0],
quality_bitmask=quality_bitmask,
**kwargs)
return [KeplerLightCurveFile(p, quality_bitmask=quality_bitmask, **kwargs)
for p in path]
def __repr__(self):
return('KeplerLightCurveFile(ID: {})'.format(self.targetid))
@property
def astropy_time(self):
"""Returns an AstroPy Time object for all good-quality cadences."""
return bkjd_to_astropy_time(bkjd=self.time)
def get_lightcurve(self, flux_type, centroid_type='MOM_CENTR'):
if flux_type in self._flux_types():
# We did not import lightcurve at the top to prevent circular imports
from .lightcurve import KeplerLightCurve
return KeplerLightCurve(
time=self.hdu[1].data['TIME'][self.quality_mask],
time_format='bkjd',
time_scale='tdb',
flux=self.hdu[1].data[flux_type][self.quality_mask],
flux_err=self.hdu[1].data[flux_type + "_ERR"][self.quality_mask],
centroid_col=self.hdu[1].data[centroid_type + "1"][self.quality_mask],
centroid_row=self.hdu[1].data[centroid_type + "2"][self.quality_mask],
quality=self.hdu[1].data['SAP_QUALITY'][self.quality_mask],
quality_bitmask=self.quality_bitmask,
channel=self.channel,
campaign=self.campaign,
quarter=self.quarter,
mission=self.mission,
cadenceno=self.cadenceno,
targetid=self.targetid,
label=self.hdu[0].header['OBJECT'],
ra=self.ra,
dec=self.dec)
else:
raise KeyError("{} is not a valid flux type. Available types are: {}".
format(flux_type, self._flux_types))
@property
def channel(self):
"""Kepler CCD channel number. ('CHANNEL' header keyword)"""
return self.header(ext=0)['CHANNEL']
@property
def obsmode(self):
"""'short cadence' or 'long cadence'. ('OBSMODE' header keyword)"""
return self.header()['OBSMODE']
@property
def pos_corr1(self):
"""Returns the column position correction."""
return self.hdu[1].data['POS_CORR1'][self.quality_mask]
@property
def poss_corr2(self):
"""Returns the row position correction."""
return self.hdu[1].data['POS_CORR2'][self.quality_mask]
@property
def quarter(self):
"""Kepler quarter number. ('QUARTER' header keyword)"""
try:
return self.header(ext=0)['QUARTER']
except KeyError:
return None
@property
def campaign(self):
"""K2 Campaign number. ('CAMPAIGN' header keyword)"""
try:
return self.header(ext=0)['CAMPAIGN']
except KeyError:
return None
@property
def mission(self):
"""'Kepler' or 'K2'. ('MISSION' header keyword)"""
try:
return self.header(ext=0)['MISSION']
except KeyError:
return None
def compute_cotrended_lightcurve(self, cbvs=[1, 2], **kwargs):
"""Returns a LightCurve object after cotrending the SAP_FLUX
against the cotrending basis vectors.
Parameters
----------
cbvs : list of ints
The list of cotrending basis vectors to fit to the data. For example,
[1, 2] will fit the first two basis vectors.
kwargs : dict
Dictionary of keyword arguments to be passed to
KeplerCBVCorrector.correct.
Returns
-------
lc : LightCurve object
CBV flux-corrected lightcurve.
"""
from .correctors import KeplerCBVCorrector
return KeplerCBVCorrector(self).correct(cbvs=cbvs, **kwargs)
class TessLightCurveFile(LightCurveFile):
"""Defines a class for a given light curve FITS file from NASA's TESS
mission.
Parameters
----------
path : str
Local path or remote url of a FITS file in TESS's lightcurve format.
quality_bitmask : str or int
Bitmask (integer) which identifies the quality flag bitmask that should
be used to mask out bad cadences. If a string is passed, it has the
following meaning:
* "none": no cadences will be ignored (`quality_bitmask=0`).
* "default": cadences with severe quality issues will be ignored
(`quality_bitmask=1130799`).
* "hard": more conservative choice of flags to ignore
(`quality_bitmask=1664431`). This is known to remove good data.
* "hardest": removes all data that has been flagged
(`quality_bitmask=2096639`). This mask is not recommended.
See the :class:`TessQualityFlags` class for details on the bitmasks.
kwargs : dict
Keyword arguments to be passed to astropy.io.fits.open.
"""
def __init__(self, path, quality_bitmask='default', **kwargs):
super(TessLightCurveFile, self).__init__(path, **kwargs)
self.quality_bitmask = quality_bitmask
self.quality_mask = TessQualityFlags.create_quality_mask(
quality_array=self.hdu[1].data['QUALITY'],
bitmask=quality_bitmask)
# Early TESS releases had cadences with time=NaN (i.e. missing data)
# which were not flagged by a QUALITY flag yet; the line below prevents
# these cadences from being used. They would break most methods!
self.quality_mask &= np.isfinite(self.hdu[1].data['TIME'])
try:
self.targetid = self.header()['TICID']
except KeyError:
self.targetid = None
def __repr__(self):
return('TessLightCurveFile(TICID: {})'.format(self.targetid))
def get_lightcurve(self, flux_type, centroid_type='MOM_CENTR'):
if flux_type in self._flux_types():
# We did not import TessLightCurve at the top to prevent circular imports
from .lightcurve import TessLightCurve
return TessLightCurve(
time=self.hdu[1].data['TIME'][self.quality_mask],
time_format='btjd',
time_scale='tdb',
flux=self.hdu[1].data[flux_type][self.quality_mask],
flux_err=self.hdu[1].data[flux_type + "_ERR"][self.quality_mask],
centroid_col=self.hdu[1].data[centroid_type + "1"][self.quality_mask],
centroid_row=self.hdu[1].data[centroid_type + "2"][self.quality_mask],
quality=self.hdu[1].data['QUALITY'][self.quality_mask],
quality_bitmask=self.quality_bitmask,
cadenceno=self.cadenceno,
targetid=self.targetid,
label=self.hdu[0].header['OBJECT'])
else:
raise KeyError("{} is not a valid flux type. Available types are: {}".
format(flux_type, self._flux_types))