transform_magnitudes#

stellarphot.utils.transform_magnitudes(input_mags, catalog, transform_catalog, input_mag_colum='mag_inst_r', catalog_mag_column='r_mag', catalog_color_column='B-V', faintest_mag_for_transform=14, sigma=2, order=1, gain=None)[source]#

Calculate catalog magnitudes and transform coefficients from instrumental magnitudes.

Parameters:

input_magsastropy.table.Table: Table which contains a column with instrumental magnitudes, i.e. -2.5 * log10(net_counts / exposure_time).
catalogastropy.table.Table: Table containing reference catalog of magnitudes and colors.
transform_catalogastropy.table.Table: Table containing the reference catalog of magnitudes and colors to use in determining the transform coefficients. Can be the same table as catalog if desired.
input_mag_columnstr, optional: Name of the column in input_mags with the magnitudes to be transformed.
catalog_mag_columnstr, optional: Name of the column in catalog with the reference magnitude.
catalog_color_columnstr, optional: Name of the column in catalog with color for each star in the catalog.
faintest_mag_for_transformfloat, optional: If this is not None, the magnitude of the faintest catalog stars to use in computing transform coefficients.
sigmafloat, optional: Number of standard deviations to use in rejecting outliers when fitting using sigma clipping.
orderint, optional: Order of the polynomial to use in fitting magnitude difference/color relationship.
gainfloat, optional: If not None, adjust the instrumental magnitude by -2.5 * log10(gain), i.e. gain correct the magnitude.

Returns:

our_cat_magsastropy.table.Column: The calculated catalog magnitudes for the stars in input_mags.
good_match_allnumpy.ndarray: Boolean array indicating which stars in input_mags have a match in the catalog.
transformsastropy.modeling.FittableModel: The coefficients of the transform. The coefficients are in the order of ascending power, i.e. the coefficient ci is the coefficient of the term x**i. Warning: This returns a namedtuple if the fit fails.