LinkedEPSFStar

class photutils.psf.LinkedEPSFStar(stars_list)

Bases: object

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.

Note that unlike EPSFStars (which is a collection of potentially unrelated stars), LinkedEPSFStar represents a single logical star observed in multiple images.

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_excluded	Whether all EPSFStar objects in this linked star have been excluded from fitting during the ePSF build process.
all_good_stars	A list of all EPSFStar objects that have not been excluded from fitting.
all_stars	A flat list of all EPSFStar objects in this linked star.
center_flat	A ndarray of the (x, y) position of all the stars' centers 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 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 in this linked star.
n_good_stars	The number of EPSFStar objects that have not been excluded from fitting.
n_stars	The number of EPSFStar objects in this linked star.

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_excluded

Whether all EPSFStar objects in this linked star have been excluded from fitting during the ePSF build process.

all_good_stars

A list of all EPSFStar objects that have not been excluded from fitting.

all_stars

A flat list of all EPSFStar objects in this linked star.

Since LinkedEPSFStar only contains EPSFStar objects (not nested LinkedEPSFStar), this is simply the internal list.

center_flat

A ndarray of the (x, y) position of all the stars’ centers 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 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 in this linked star.

For LinkedEPSFStar this is the same as n_stars since there is no nesting.

n_good_stars

The number of EPSFStar objects that have not been excluded from fitting.

n_stars

The number of EPSFStar objects in this linked star.

For LinkedEPSFStar this is the same as n_all_stars since there is no nesting.

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.