sncosmo.read_snana_simlib¶
- sncosmo.read_snana_simlib(fname)[source]¶
Read an SNANA ‘simlib’ (simulation library) ascii file.
- Parameters:
- fnamestr
Filename.
- Returns:
- meta
OrderedDict
Global meta data, not associated with any one LIBID. If DOCANA is present, it is stored in
meta['DOCUMENTATION']
.- observation_sets
OrderedDict
ofastropy.table.Table
keys are LIBIDs, values are observation sets.
- meta
Notes
Anything following ‘#’ on each line is ignored as a comment.
Keywords are space separated strings ending wth a colon.
If a line starts with ‘LIBID:’, the following lines are associated with the value of LIBID, until ‘END_LIBID:’ is encountered.
While reading a given LIBID, lines starting with ‘S’ or ‘T’ keywords are assumed to contain 12 space-separated values after the keyword. These are (1) MJD, (2) IDEXPT, (3) FLT, (4) CCD GAIN, (5) CCD NOISE, (6) SKYSIG, (7) PSF1, (8) PSF2, (9) PSF 2/1 RATIO, (10) ZPTAVG, (11) ZPTSIG, (12) MAG.
Column (2) may represent co-added observations in a ‘111*1’ format. In this case, the ‘IDEXPT’ column is split at the ‘*’ into ‘IDEXPT’ and ‘NEXPOSE’
Other lines inside a ‘LIBID:’/’END_LIBID:’ pair are treated as metadata for that LIBID.
Any other keywords outside a ‘LIBID:’/’END_LIBID:’ pair are treated as global header keywords and are returned in the
meta
dictionary.
Examples
>>> meta, obs_sets = read_snana_simlib('filename')
The second object is a dictionary of astropy Tables indexed by LIBID:
>>> obs_sets.keys() [0, 1, 2, 3, 4]
Each table (libid) has metadata:
>>> obs_sets[0].meta OrderedDict([('LIBID', 0), ('RA', 52.5), ('DECL', -27.5), ('NOBS', 161), ('MWEBV', 0.0), ('PIXSIZE', 0.27)])
Each table has the following columns:
>>> obs_sets[0].colnames ['SEARCH', 'MJD', 'IDEXPT', 'FLT', 'CCD_GAIN', 'CCD_NOISE', 'SKYSIG', 'PSF1', 'PSF2', 'PSFRATIO', 'ZPTAVG', 'ZPTSIG', 'MAG']