StarID.project_stars

giant.stellar_opnav.star_identification:

StarID.project_stars(epoch=datetime.datetime(2000, 1, 1, 0, 0), compute_weights=False, temperature=0, image_number=0)[source]

This method queries the star catalogue for predicted stars within the field of view and projects those stars onto the image using the camera model.

The star catalogue is queried using the query_catalogue() method and the stars are updated to the epoch specified by epoch using the proper motion from the catalogue. The epoch should be specified as either a datetime object representing the UTC time the stars should be transformed to, or a float value representing the MJD year. The queried Pandas Dataframe containing the star catalogue records is stored in the queried_catalogue_star_records attribute.

After the stars are queried from the catalogue, they are converted to inertial unit vectors and corrected for stellar aberration and parallax using the camera_position and camera_velocity values. The corrected inertial vectors are stored in the queried_catalogue_unit_vectors.

Finally, the unit vectors are rotated into the camera frame using the a_priori_rotation_cat2camera attribute, and then projected onto the image using the model attribute. The projected points are stored in the queried_catalogue_image_points attribute.

If requested, the formal uncertainties for the catalogue unit vectors and pixel locations are computed and stored in the queried_weights_inertial and queried_weights_picture. These are computed by transforming the formal uncertainty on the right ascension, declination, and proper motion specified in the star catalogue into the proper frame.

In general this method is not called directly by the user and instead is called in the id_stars() method.

Parameters:

  • epoch (datetime | Real) – The epoch to get the star locations for

  • compute_weights (bool) – A boolean specifying whether to compute the formal uncertainties for the unit vectors and the pixel locations of the catalogue stars.

  • temperature (Real) – The temperature of the camera at the time of the image being processed

  • image_number (int) – The number of the image being processed