The ASDF-standard contains a few astronomy-specific tags that are optional but maintained as part of the standard (for historical reasons). These include:
.. asdf-autoschemas:: fits/fits-1.1.0 table/column-1.1.0 table/table-1.1.0 time/time-1.2.0 unit/unit-1.0.0 unit/defunit-1.0.0 unit/quantity-1.2.0