VOUnits 1.1 RFC

[Steve Allen]

On Fri 2023-06-30T17:59:38+0200 Markus Demleitner hath writ:
> * Clarified: that Besselian year is not in FITS.

I am mystified at this change.

Refer to the fields found in the original SAO catalog

https://heasarc.gsfc.nasa.gov/W3Browse/star-catalog/sao.html

If the original SAO catalog is stored in a FITS table there
will be fields

RA_Epoch
Dec_Epoch

Those were expressed along with coordinates in the FK4 system,
therefore the units of those epochs will be Besselian years.
Unless I am mistaken the proper motions in the SAO catalog
are also expressed as motion per Besselian year.

The reason that we listed Besselian years in the FITS time paper was
in order to provide a notation for a machine to have correct
interpretation of the units of quantities in tables which were
transcribed directly from original sources which used those units.

I do not see how FITS can reject the notion that it contains
the Besselian year unless it is being decided to discard much
of the astronomical data from before I was born.

--
Steve Allen                    <sla at ucolick.org>              WGS-84 (GPS)
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