spacetelescope/jwst-calibration-field

jwcf - JWST calibration field catalogs

Python interface to the HAWK-I and HST-based JWST calibration field catalogs. Both of these catalogs have RA, Dec positions as well as estimated magnitudes for most JWST instruments+filters.

Example usage

Access HAWK-I based catalog:

    from jwcf import hawki 
    catalog = hawki.hawki_catalog() 

Access HST based catalog:

    from jwcf import hst
    catalog = hst.hst_catalog(decimal_year_of_observation=2022.50)

decimal_year_of_observation above provides the RA, Dec locations at the desired epoch. These locations are projected based on accurate HST proper motions derived using dual-epoch data obtained in 2006.39 and 2017.38. If decimal_year_of_observation is not provided, the output catalog will default to 2017.38 positions.

The resulting catalog above is an astropy table (class). Available columns can be accessed by catalog.colnames. To extract a specific column: e.g., catalog['ra_deg'] as a table column or catalog['ra_deg'].data as a (masked) array.

Documentation

Anderson, J., Fall, M., and the Astrometry Working Group, The JWST Calibration Field: Absolute Astrometry and Proper Motions with GAIA and a Second HST Epoch, Technical Report JWST-STScI-007716, STScI

Sahlmann, J., 2019, Astrometric catalog for JWST focal plane geometric calibration, Technical Report JWST-STScI-006828 STScI

Sahlmann, J., 2017, Astrometric accuracy of the JWST calibration field astrometric catalog examined with the first Gaia data release, Technical Report JWST-STScI-005492, STScI

Contributing

Please open a new issue or new pull request for bugs, feedback, or new features you would like to see. If there is an issue you would like to work on, please leave a comment and we will be happy to assist. New contributions and contributors are very welcome!

References

jwst-calibration-field's Issues

add HST catalog that is deeper but has smaller footprint

The single-epoch HST catalog can be found here: https://grit.stsci.edu/NIRISS/commissioning/imc-catalog

The preliminary version of the two-epoch HST catalog is available at http://www.stsci.edu/~jayander/JWST_CALFIELD2019/
(see the preliminary report at https://innerspace.stsci.edu/pages/viewpage.action?spaceKey=AWG&title=Reports)

add VMC catalog in a ~20 arcmin radius around the HST field center

The VMC catalog is now public: https://www.eso.org/sci/publications/announcements/sciann17232.html

The absolute and relative astrometric accuracy will have to be checked against Gaia DR2.