Coverage for python/lsst/sims/photUtils/LSSTdefaults.py : 53%

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1from builtins import object
2import numpy
4__all__ = ["LSSTdefaults"]
6class LSSTdefaults(object):
7 """
8 This class exists to store default values of seeing, m5, and gamma taken from the over
9 view paper (arXiv 0805.2366, Table 2, 29 August 2014 version)
10 """
12 def __init__(self):
13 # Standard FWHMeffective in arcseconds
14 self._FWHMeff = {'u':0.92, 'g':0.87, 'r':0.83, 'i':0.80, 'z':0.78, 'y':0.76}
15 # Expected effective wavelength for throughput curves, in nanometers
16 self._effwavelen = {'u':367.0, 'g':482.5, 'r':622.2, 'i':754.5, 'z':869.1, 'y':971.0}
17 # Expected m5 depths (using FWHMeffective + dark sky + X=1.2 atmosphere + throughput curves)
18 self._m5 = {'u':23.68, 'g':24.89, 'r':24.43, 'i':24.00, 'z':24.45, 'y':22.60}
19 self._gamma = {'u':0.037, 'g':0.038, 'r':0.039, 'i':0.039, 'z':0.040, 'y':0.040}
22 def m5(self, tag):
23 """
24 From arXiv 0805.2366 (Table 2):
26 Typical 5-sigma depth for point sources at zenith, assuming
27 exposure time of 2 x 15 seconds and observing conditions as listed.
28 Calculated using $SYSENG_THROUGHPUT curves as of 11/25/2015, using
29 $SYSENG_THROUGHPUT/python/calcM5.py
31 @param [in] the name of a filter i.e. 'u', 'g', 'r', 'i', 'z', or 'y'
33 @param [out] the corresponding m5 value
34 """
35 return self._m5[tag]
38 def FWHMeff(self, tag):
39 """
40 From arXiv 0805.2366 XXX version (Table 2):
42 The expected FWHMeff in arcseconds. This is the width of a single gaussian
43 which produces the appropriate number of effective pixels in the PSF (thus 'FWHMeff').
44 This is the value to use for calculating Neffective, when Neffective assumes a single gaussian.
45 It can be converted to a geometric FWHM (equivalent to the approximate value which would
46 be measured across a van Karmen PSF profile) using SignalToNoise.FWHMeff2FWHMgeom.
48 @param [in] the name of a filter i.e. 'u', 'g', 'r', 'i', 'z', or 'y'
50 @param [out] the corresponding FWHMeff
51 """
53 return self._FWHMeff[tag]
55 def effwavelen(self, tag):
56 """
57 From the throughput curves in syseng_throughputs, calculated by
58 $SYSENG_THROUGHPUTS/python/effectiveWavelen.py
59 as of 11/25/2015.
60 """
61 return self._effwavelen[tag]
64 def gamma(self, tag):
65 """
66 See Table 2 and Equaiton 5 of arXiv 0805.2366 29 August 2014 version.
68 @param [in] the name of a filter i.e. 'u', 'g', 'r', 'i', 'z', or 'y'
70 @param [out] the corresponding value of gamma as defined in the
71 reference above
72 """
74 return self._gamma[tag]