On 20 Feb, 00:40, HW@....(Henri Wilson) wrote:
On 19 Feb 2007 05:32:38 -0800, "George Dishman" wrote:
On 19 Feb, 05:09, HW@....(Henri Wilson) wrote:
Too close, moving too slowly...

The distance is usually known from Hipparcos or
so far away that it is academic for this purpose.

The velocity can be determined from the spectrum
of course and your program is then supposed to
tell us the velocity, but in general nearby stars
that are too close to resolve must be moving quite
fast.

George, my program DOES NOT tell us anything about the maximum velocity.
Where did you get the idea that it does?


You fit the blue curve to the observed velocity curve
or the green curve to the observed brightness and the
red curve tells you the actual velocity curve.

To do that you can change the orbital parameters within
Keplerian constraints, inclination and yaw for the
observer location and the extinction characteristic
distance but that's all.

If you can fit both the blue and green curves, including
their relative phase, with a single set of parameters
then you theory passes the test otherwise you look for
excuses (like it really is a Cepheid).

I tried to expain this to Andersen in the case of HD10875

Which of the above did you suggest applied?

The addition of two sine curves 180 out...... plus extinction.

And did you provide him with spectroscopic evidence that
the intrinsic luminosities are that well matched?

Yes I do, it would make a difference of about
45 parts per million to the critical distance
for the pulsar for example (mental arithmetic,
E&OE).

George, measurements made on Earth about the rate of change of velocity in the
Earth's gravity field don't really tell us much about the possible role that
the whole solar gravity field might play in regard to a local EM frame of
reference, if such exists.

You still haven't learnt what the phrase "frame of reference"
means Henry.

Light entering that frame from outside and initially moving at c+v wrt Earth
might be affected much more than you think.

Nope, for weak fields Newton holds or you can use GR. Ignoring
the refractive index of the solar plasma, the speed becomes:

v_r^2 = v_i^2 + v_e^2

where v_r is at radius r from the Sun, v_i is the speed at
infinity or in deep space, the final value of c/n we talked
about before, and v_e is the escape velocity at that radius.

However I basically agree with what you say. Gravity is probably too weak to be
a major factor.

It's easy to quantify but even if you dispute the above
maths, since it is going to affect all the light equally
it cannot have any effect at the observer end. At the
emitted end it just slows all the light leaving the star
so the light spends longer in the region where extinction
happens so the speed difference between fast and slow will
be reduced, but only by a tiny amount.

George