In article , George Dishman
writes:

"Jonathan Silverlight" wrote in message
...
In message , oriel36
writes
.....
Proper motions of stars are pre-galactic notions besides they contain
elements of the celestial sphere in position descriptions of external
galaxies.

Could someone translate this into standard English?

It's not easy but I'll give it a go:

a) So-called "proper motions" of stars are actually
an illusion caused by rotation of the Milky Way.

To some extent, yes, but stars also have a peculiar motion, i.e. a real
motion through space. Observed proper motion is a combination of this
and the "illusion" referred to above.

b) The Earth rotates through 360 degrees in a solar
day, not a sidereal day as astronomers think,
therefore the concept of right ascension as a
means of documenting the location of stars is
flawed.

There is, of course, an extragalactic reference frame, defined via
quasars. While this is somewhat problematic if quasars show a proper
motion, ON AVERAGE they will probably have a negligible proper motion
and/or the higher redshift quasars (at least in the standard paradigm)
will have a negligible proper motion. (I'm not very familiar with it,
but I would suspect that this reference frame is defined via
high-redshift quasars.)