"OG" napisal w wiadomosci
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On 30/10/2011 15:37, Szczepan Bialek wrote:

It seems to me that the only way to measure the angle of refraction is to
measure the absorption line position.

You are mistaken. Arago's experiment simply looked at the angle or
refraction.

But the line position was the same for stars:
"http://www.archive.org/stream/spectrumanalysis00esterich/spectrumanalysis00esterich_djvu.txt
"Indeed, these observations would scarcely be
possible, were it not that in the dark lines crossing the spec-
tra of the sun and fixed stars, the places of some of which
may be accurately ascertained, we have fixed positions in
the spectrum, the degree of refrangibility or wave-length of
which may be determined beforehand, both for the sun and
terrestrial substances, and also for the stars or other sources
of light supposed to be at rest. "


Below is the problem of the radial speeds of planets. Also the result is
null:
http://articles.adsabs.harvard.edu//...00243.000.html

You are mistaken. That experiment was to detect oxygen lines in the
atmosphere of Venus.

You are right.


The Vogel's result do not fit to them.

Why not?

In all textbooks is wrote that Arago, Mchelson-Morley and
Truton-Noble
fit
together.

So what (in your own words) is the problem with Vogel's result?

The problem will appear if it is confirmed.

What problem?

Now it is mentioned only in Wiki. Without any comments.
If it is right than: "This experiment, which
demonstrated the effect of the earth's orbital movement on refraction
is of great historical interest. "

Arago's result yes.

I still don't know why you think there's a problem with Vogel's result.

I know that in the whole World students are told that at measuring of the
radial speed of stars they should take into account the orbital speed of
the
Earth.

Yes.

The reason is the Vogel's result.

Sort of. More accurately, Vogel's result is a measurement of the earth's
orbital speed, hence, it needs to be taken into account.

Arago's result is "yes" and Vogel's result is "yes". Is it possible?

It is some problem because in 1905 Einstein wrote that it is impossible
to
detect the orbital speed. So are the two possibilities:
1. Brace and Einstein did not know about Vogel's result.
2. Vogel's result become wrong.

You are mistaken. Einstein wrote no such thing. What he wrote (in effect)
is that the earth's orbital speed has no effect on the measured speed of
light, which is the explanation behind Arago's null result.

For me refraction = line position ("the dark lines crossing the spectra of
the sun and fixed stars").
The only detail which can be measured are the position of that dark lines.
Arago used the achromatic prism. But the next used the dark lines.

But is possible that Arago's measurements and that to 1904 were not
accurate.
Why than the Vogel's result is totally unknown?
S*