Solar coordinates

[Arnold Rots]

At the risk of sounding pedantic, William Thompson writes:

> ...
> This ambiguity could be removed by including an additional keyword to define
> exactly what surface is meant.  I suggest that the keyword SOLAR_R be defined
> as an optional keyword whose meaning would be the apparent solar radius in
> kilometers of the surface used in determining the solar latitude and longitude.
> If omitted, the default value would be the photospheric value.
> ...
> Kilometers: Expressing the data as a physical distance removes all ambiguity
> 	due to either observing distance or to solar radius definition.
> ...
> William Thompson
> 
> 

Let's not forget that the FITS standard prescribes (or, at least,
strongly recommends) SI units.  Meters would be more appropriate.

  - Arnold Rots