Muff Diver wrote:

separately posted to alt.astronomy and rec.org.mensa

Cross-posting is simpler, don't you think, keeping the thread in one piece?

[snip]

In the case of our solar system, one star
among many in our galaxy, it would only
be practical to regress the motion of the galaxy
in a long term regression of apparent motion.
Question is still "what direction, what velocity?".

I believe the princpal technique used involves averaging the apparent
space motion of a great many stars. Obviously the value obtained will
depend on the objects selected, so different surveys have arrived at
various results. According to _Burnham's Celestial Handbook_ (1978)
the "Solar Apex" lies in the general direction of the star Vega
(Alpha Lyrae), and we're heading towards it at something like 12 mps
(19 km/s). The most recent survey he cites was conducted in 1967 and
included 25,800 stars, placing the Solar Apex "very near the star 4
Cygni"; in 2000.0 coordinates this is roughly RA 19.5h, Dec +36°.

--Odysseus