ASTReducer

class delphinus.artstars.ASTReducer(fakeReader, photTable)

Bases: object

Reduce artificial star tests to yield error estimates for individual stars, completeness estimates for individual stars, and 50% completeness limits for individual bands.

Parameters :

fakeReader : delphinus.phottable.FakeReader

A FakeReader instance with all artificial stars. Note that multiple FakeReader instances to can be added together to combine multiple artificial star tests.

photTable : delphinus.phottable.DolphotTable

A DolphotTable instance.

Methods Summary

completeness_limits([frac, mag_err_lim, dx_lim])	Compute the completeness limit for each image.
compute_errors([mag_err_lim, dx_lim])	Estimates errors and completeness per star.

Methods Documentation

completeness_limits(frac=0.5, mag_err_lim=None, dx_lim=None)

Compute the completeness limit for each image. The magnitude at the completeness limit is saved as a an attribute to the phot table in the HDF5 file.

Parameters :

frac : float

Scalar fractional level of completeness. For example, 0.5 is the 50% completeness limit.

mag_err_lim : float

Maximum absolute difference in magnitudes, in any band, for the star to be considered recovered.

dx_lim : float

Maximum distance between a fake star’s input site and its observed site for the fake star to be considered recovered.

compute_errors(mag_err_lim=None, dx_lim=None)

Estimates errors and completeness per star.

Load photometry from fake table (from same chip, ext as primary data. For each star in the phot table, get its magnitude. Use a kdtree to get the N most similar stars; compute statistics

Parameters :

frac : float

Scalar fractional level of completeness. For example, 0.5 is the 50% completeness limit.

mag_err_lim : float

Maximum absolute difference in magnitudes, in any band, for the star to be considered recovered.

dx_lim : float

Maximum distance between a fake star’s input site and its observed site for the fake star to be considered recovered.