MakeRawVisitInfo¶
- class lsst.obs.base.MakeRawVisitInfo(log=None, doStripHeader=False)¶
Bases:
object
Base class functor to make a VisitInfo from the FITS header of a raw image.
A subclass will be wanted for each camera. Subclasses should override:
setArgDict
, The override can call the base implementation,which simply sets exposure time and date of observation
The design philosophy is to make a best effort and log warnings of problems, rather than raising exceptions, in order to extract as much VisitInfo information as possible from a messy FITS header without the user needing to add a lot of error handling.
However, the methods that transform units are less forgiving; they assume the user provides proper data types, since type errors in arguments to those are almost certainly due to coding mistakes.
- Parameters:
- log
logging.Logger
or None Logger to use for messages. (None to use
logging.getLogger("lsst.obs.base.makeRawVisitInfo")
).- doStripHeader
bool
, optional Strip header keywords from the metadata as they are used?
- log
Methods Summary
__call__
(md, exposureId)Construct a VisitInfo and strip associated data from the metadata.
Convert zenith distance to altitude (lsst.afw.geom.Angle)
centigradeFromKelvin
(tempK)Convert temperature from Kelvin to Centigrade
defaultMetadata
(value, defaultValue[, ...])Return the value if it is not NaN and within min/max, otherwise return defaultValue.
eraFromLstAndLongitude
(lst, longitude)Return an approximate Earth Rotation Angle (afw:Angle) computed from local sidereal time and longitude (both as afw:Angle; Longitude shares the afw:Observatory covention: positive values are E of Greenwich).
getDarkTime
(argDict)Get the darkTime from the DARKTIME keyword, else expTime, else NaN,
getDateAvg
(md, exposureTime)Return date at the middle of the exposure.
offsetDate
(date, offsetSec)Return a date offset by a specified number of seconds.
pascalFromMBar
(mbar)Convert pressure from millibars to Pascals
pascalFromMmHg
(mmHg)Convert pressure from mm Hg to Pascals
pascalFromTorr
(torr)Convert pressure from torr to Pascals
popAngle
(md, key[, units])Pop an lsst.afw.geom.Angle, whose metadata is in the specified units, with a default of Nan
popFloat
(md, key)Pop a float with a default of NaN.
popIsoDate
(md, key[, timesys])Pop a FITS ISO date as an lsst.daf.base.DateTime
popItem
(md, key[, default])Return an item of metadata.
popMjdDate
(md, key[, timesys])Get a FITS MJD date as an
lsst.daf.base.DateTime
.setArgDict
(md, argDict)Fill an argument dict with arguments for VisitInfo and pop associated metadata
Methods Documentation
- __call__(md, exposureId)¶
Construct a VisitInfo and strip associated data from the metadata.
- Parameters:
- md
lsst.daf.base.PropertyList
orlsst.daf.base.PropertySet
Metadata to pull from. Items that are used are stripped from the metadata (except TIMESYS, because it may apply to other keywords) if
doStripHeader
.- exposureId
int
exposure ID
- md
Notes
The basic implementation sets
date
andexposureTime
using typical values found in FITS files and logs a warning if neither can be set.
- static altitudeFromZenithDistance(zd)¶
Convert zenith distance to altitude (lsst.afw.geom.Angle)
- static centigradeFromKelvin(tempK)¶
Convert temperature from Kelvin to Centigrade
- static defaultMetadata(value, defaultValue, minimum=None, maximum=None)¶
Return the value if it is not NaN and within min/max, otherwise return defaultValue.
- static eraFromLstAndLongitude(lst, longitude)¶
Return an approximate Earth Rotation Angle (afw:Angle) computed from local sidereal time and longitude (both as afw:Angle; Longitude shares the afw:Observatory covention: positive values are E of Greenwich).
NOTE: if we properly compute ERA via UT1 a la DM-8053, we should remove this method.
- getDarkTime(argDict)¶
Get the darkTime from the DARKTIME keyword, else expTime, else NaN,
If dark time is available then subclasses should call this method by putting the following in their
__init__
method:argDict['darkTime'] = self.getDarkTime(argDict)
- getDateAvg(md, exposureTime)¶
Return date at the middle of the exposure.
- Parameters:
- md
lsst.daf.base.PropertyList
orPropertySet
Metadata to pull from. Items that are used are stripped from the metadata (except TIMESYS, because it may apply to other keywords).
- exposureTime
float
Exposure time (sec)
- md
Notes
Subclasses must override. Here is a typical implementation:
dateObs = self.popIsoDate(md, "DATE-OBS") return self.offsetDate(dateObs, 0.5*exposureTime)
- offsetDate(date, offsetSec)¶
Return a date offset by a specified number of seconds.
- date
lsst.daf.base.DateTime
Date baseline to offset from.
- offsetSec
float
Offset, in seconds.
- Returns:
lsst.daf.base.DateTime
The offset date.
- date
- static pascalFromMBar(mbar)¶
Convert pressure from millibars to Pascals
- static pascalFromMmHg(mmHg)¶
Convert pressure from mm Hg to Pascals
Notes
Could use the following, but astropy.units.cds is not fully compatible with Python 2 as of astropy 1.2.1 (see https://github.com/astropy/astropy/issues/5350#issuecomment-248612824): astropy.units.cds.mmHg.to(astropy.units.pascal, mmHg)
- static pascalFromTorr(torr)¶
Convert pressure from torr to Pascals
- popAngle(md, key, units=Unit('deg'))¶
Pop an lsst.afw.geom.Angle, whose metadata is in the specified units, with a default of Nan
The angle may be specified as a float or sexagesimal string with 1-3 fields.
- Parameters:
- md
lsst.daf.base.PropertyList
orPropertySet
Metadata to pull
key
from.- key
str
Key to read from md.
- md
- Returns:
lsst.afw.geom.Angle
Value of the requested key as an angle; Angle(NaN) if the key is not found.
- popFloat(md, key)¶
Pop a float with a default of NaN.
- popIsoDate(md, key, timesys=None)¶
Pop a FITS ISO date as an lsst.daf.base.DateTime
- Parameters:
- Returns:
lsst.daf.base.DateTime
Value of the requested date;
DateTime()
if the key is not found.
- popItem(md, key, default=None)¶
Return an item of metadata.
The item is removed if
doStripHeader
isTrue
.Log a warning if the key is not found.
- popMjdDate(md, key, timesys=None)¶
Get a FITS MJD date as an
lsst.daf.base.DateTime
.- Parameters:
- Returns:
lsst.daf.base.DateTime
Value of the requested date;
DateTime()
if the key is not found.
- setArgDict(md, argDict)¶
Fill an argument dict with arguments for VisitInfo and pop associated metadata
Subclasses are expected to override this method, though the override may wish to call this default implementation, which:
sets exposureTime from “EXPTIME”
sets date by calling getDateAvg
- Parameters:
- md
lsst.daf.base.PropertyList
orPropertySet
Metadata to pull from. Items that are used are stripped from the metadata (except TIMESYS, because it may apply to other keywords).
- argdict
dict
dict of arguments
- md
Notes
Subclasses should expand this or replace it.