FieldError for "r" column in MPC ephemeris

[phtnnz]

High-level problem description
FieldError raised for querying MPC ephemeris for a particular object and time (epoch)

What did you do?

    loc = EarthLocation(lat=-23.23639*u.deg, lon=16.36167*u.deg , height=1825*u.m) # M49, Hakos, Namibia
    obj = "2026 JH2"

    ## Working example
    epochs = {"start":  Time('2026-05-20 00:00:00.000'),
              "step":   30 * u.min,
              "stop":   Time('2026-05-20 06:00:00.000')
             }
    eph = Ephem.from_mpc(obj, location=loc, epochs=epochs)
    ic(eph)

    ## This epochs setting raises a FieldError exception
    epochs = {"start":  Time('2026-05-19 00:00:00.000'),
              "step":   30 * u.min,
              "stop":   Time('2026-05-19 06:00:00.000')
             }
    eph = Ephem.from_mpc(obj, location=loc, epochs=epochs)
    ic(eph)

What did you expect?
Both code snippets should output the ephemeris for the requested epochs range.

What did really happen?
The second epochs setting raises a FieldError as follows

WARNING: column r has a unit but is kept as a Column as an attempt to convert it to Quantity failed with:
TypeError('The value must be a valid Python or Numpy numeric type.') [astropy.table.table]
Traceback (most recent call last):
  File "D:\Users\mj\src\python\astropy-workbench\test-ephem-error.py", line 61, in <module>
    main()
  File "D:\Users\mj\src\python\astropy-workbench\test-ephem-error.py", line 55, in main
    eph = Ephem.from_mpc(obj, location=loc, epochs=epochs)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\Users\mj\src\python\astropy-workbench\venv\Lib\site-packages\sbpy\utils\decorators.py", line 78, in wrapper
    return wrapped_function(*func_args, **func_kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\Users\mj\src\python\astropy-workbench\venv\Lib\site-packages\sbpy\bib\core.py", line 183, in wrapper
    result = f(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^
  File "D:\Users\mj\src\python\astropy-workbench\venv\Lib\site-packages\sbpy\data\ephem\core.py", line 534, in from_mpc
    return cls.from_table(all_eph)
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\Users\mj\src\python\astropy-workbench\venv\Lib\site-packages\sbpy\data\core.py", line 514, in from_table
    tab.table = QTable(table, meta={**table.meta, **meta}, **kwargs)
    ^^^^^^^^^
  File "D:\Users\mj\src\python\astropy-workbench\venv\Lib\site-packages\sbpy\data\core.py", line 743, in table
    self.verify_fields()
  File "D:\Users\mj\src\python\astropy-workbench\venv\Lib\site-packages\sbpy\data\core.py", line 922, in verify_fields
    raise FieldError(
sbpy.data.core.FieldError: Field r is not an instance of <class 'astropy.units.quantity.Quantity'>

Querying the MPC ephemeris service on the web shows an valid "r" column for both dates.

Provide information on your environment:
Windows 11, Python 3.12
sbpy version: 0.6.0
astropy version: 7.2.0
numpy version: 2.3.5

[mkelley]

Thanks for the report. This is not an sbpy issue, but a problem with astroquery. So, I'll close this issue, and I have opened a fix for astroquery at astropy/astroquery#3594