Given input ra, dec coordinates, uses the astroquery package to download the same frame from a selected catalog.

Both catalogs are then matched using astropy's match_to_catalog_sky.

Currently, only Vizier catalogs can be queried. To obtain the list of supported catalogs in Vizier, try the following in a Python session (in this example, I search for GAIA2 data):

from astroquery.vizier import Vizier
catalog_list = Vizier.find_catalogs('gaia 2')
print(Vizier.get_catalogs(catalog_list.keys()))

In this case, the GAIA2 data is in the I/345 catalog.

Requires the conda package manager: https://conda.io/miniconda.html

After conda is installed,create an environment and install the required packages with:

$ conda create -n cat-match matplotlib numpy scipy astropy

Then activate the environment:

$ conda activate cat-match

After a successful activation, the terminal session should look like:

(cat-match) $

Finally, install the astroquery package:

(cat-match) $ conda install -c astropy astroquery

After downloading and extracting the repository, rename the params_input_def.dat to params_input.dat.

Put a file in the /input folder and set the proper parameters in the params_input.dat file.

Run with:

(cat-match) $ python catalog-match.py

The code outputs three .dat files:

• cluster_match.dat: file with the cross-matched stars.
• cluster_no_match.dat: file with the stars that could not be cross-matched.
• cluster_query.dat: file with the queried catalog data.

and one .png file:

• cluster.png: figures showing the crossed-matched stars and more.

which looks like this: