transform_pm_cov

gala.coordinates.transform_pm_cov(c, cov, to_frame)

Transform a proper motion covariance matrix to a new frame.

Parameters:

c : SkyCoord

The sky coordinates of the sources in the initial coordinate frame.

cov : array_like

The covariance matrix of the proper motions. Must have same length as the input coordinates.

to_frame : BaseCoordinateFrame subclass

The frame to transform to as an Astropy coordinate frame class or instance.

Returns:

new_cov : array_like

The transformed covariance matrix.