LinkedEPSFStar

class photutils.psf.LinkedEPSFStar(stars_list)

Bases: EPSFStars

A class to hold a list of EPSFStar objects for linked stars.

Linked stars are EPSFStar cutouts from different images that represent the same physical star. When building the ePSF, linked stars are constrained to have the same sky coordinates.

Parameters:

stars_listlist of EPSFStar objects

A list of EPSFStar objects for the same physical star. Each EPSFStar object must have a valid wcs_large attribute to convert between pixel and sky coordinates.

Attributes Summary

all_good_stars	A list of all EPSFStar objects stored in this object that have not been excluded from fitting, including those that comprise linked stars (i.e., LinkedEPSFStar), as a flat list.
all_stars	A list of all EPSFStar objects stored in this object, including those that comprise linked stars (i.e., LinkedEPSFStar), as a flat list.
center_flat	A ndarray of the (x, y) position of all the stars' centers (including linked stars) with respect to the original (large) image (not the cutout image) as a 2D array (n_all_stars x 2).
cutout_center_flat	A ndarray of the (x, y) position of all the stars' centers (including linked stars) with respect to the input cutout data array, as a 2D array (n_all_stars x 2).
n_all_stars	The total number of EPSFStar objects, including all the linked stars within LinkedEPSFStar.
n_good_stars	The total number of EPSFStar objects, including all the linked stars within LinkedEPSFStar, that have not been excluded from fitting.
n_stars	The total number of stars.

Methods Summary

constrain_centers()

Constrain the centers of linked EPSFStar objects (i.e., the same physical star) to have the same sky coordinate.

Attributes Documentation

all_good_stars

A list of all EPSFStar objects stored in this object that have not been excluded from fitting, including those that comprise linked stars (i.e., LinkedEPSFStar), as a flat list.

all_stars

A list of all EPSFStar objects stored in this object, including those that comprise linked stars (i.e., LinkedEPSFStar), as a flat list.

center_flat

A ndarray of the (x, y) position of all the stars’ centers (including linked stars) with respect to the original (large) image (not the cutout image) as a 2D array (n_all_stars x 2).

Note that when EPSFStars contains any LinkedEPSFStar, the center attribute will be a nested 3D array.

cutout_center_flat

A ndarray of the (x, y) position of all the stars’ centers (including linked stars) with respect to the input cutout data array, as a 2D array (n_all_stars x 2).

Note that when EPSFStars contains any LinkedEPSFStar, the cutout_center attribute will be a nested 3D array.

n_all_stars

The total number of EPSFStar objects, including all the linked stars within LinkedEPSFStar.

Each linked star is included in the count.

n_good_stars

The total number of EPSFStar objects, including all the linked stars within LinkedEPSFStar, that have not been excluded from fitting.

Each non-excluded linked star is included in the count.

n_stars

The total number of stars.

A linked star is counted only once.

Methods Documentation

constrain_centers()

Constrain the centers of linked EPSFStar objects (i.e., the same physical star) to have the same sky coordinate.

Only EPSFStar objects that have not been excluded during the ePSF build process will be used to constrain the centers.

The single sky coordinate is calculated as the mean of sky coordinates of the linked stars.