In message , Dr John Stockton
writes
JRS: In article .com
, dated Mon, 9 Jan 2006 20:07:24 local, seen in news:sci.astro,
posted :

If you are an Einstein subscriber, and apply c=c+v to radar ranging of
the sun,(sic planets)
the astronomical unit varies up to 274,000kms whether measured at dawn
(radar approaching sun) or dusk (retreating).

Since the Astronomical Unit is defined as the *mean* distance between
earth and sun, your conclusion would be wrong even if your speed
argument were otherwise correct, which it is not.

The definition does not depend on the measurement method.

Moreover, ISTR that the AU is not determined by ranging the Sun (which
has a rather uncertain surface well away from its middle) but by ranging
other planets, such as Venus.

A bit of rummaging around on the Web shows that the definition is a lot
more complex than that. This seems typical
" the radius of an unperturbed circular orbit a massless body would
revolve about the sun in 2*(pi)/k days (i.e., 365.2568983.... days),
where k is defined as the Gaussian constant exactly equal to
0.01720209895." http://neo.jpl.nasa.gov/glossary/au.html
He's wrong about c'=c+v, too. Or "not even wrong".