"""Reader for K2 EVEREST light curves."""
from ..lightcurve import KeplerLightCurve
from ..utils import KeplerQualityFlags
from .generic import read_generic_lightcurve
[docs]def read_everest_lightcurve(
filename, flux_column="flux", quality_bitmask="default", **kwargs
):
"""Read an EVEREST light curve file.
More information: https://archive.stsci.edu/hlsp/everest
Parameters
----------
filename : str
Local path or remote url of a Kepler light curve FITS file.
flux_column : 'pdcsap_flux' or 'sap_flux'
Which column in the FITS file contains the preferred flux data?
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.
Returns
-------
lc : `KeplerLightCurve`
A populated light curve object.
"""
lc = read_generic_lightcurve(
filename,
flux_column=flux_column,
quality_column="quality",
cadenceno_column="cadn",
time_format="bkjd",
)
# Filter out poor-quality data
# NOTE: Unfortunately Astropy Table masking does not yet work for columns
# that are Quantity objects, so for now we remove poor-quality data instead
# of masking. Details: https://github.com/astropy/astropy/issues/10119
quality_mask = KeplerQualityFlags.create_quality_mask(
quality_array=lc["quality"], bitmask=quality_bitmask
)
lc = lc[quality_mask]
lc.meta["AUTHOR"] = "EVEREST"
lc.meta["TARGETID"] = lc.meta.get("KEPLERID")
lc.meta["QUALITY_BITMASK"] = quality_bitmask
lc.meta["QUALITY_MASK"] = quality_mask
return KeplerLightCurve(data=lc, **kwargs)