Thread: Radio Astronomy
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Old November 9th 11, 01:07 PM posted to rec.radio.amateur.antenna
Jeff[_14_] Jeff[_14_] is offline
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First recorded activity by RadioBanter: Dec 2010
Posts: 87
Default Radio Astronomy


Once mo
""In 1818 Arago found that the refraction of a prism for star light
was the
same for light incident in the direction of the earth's orbital
velocity v
as for that coming in the opposite direction. This unexpected null result
was explained that same year by Fresnel's ether-dray theory, which
assumed
partial ether entrainment in transparent media by an amount depending
upon
the first power of v." From: http://www.3rd1000.com/chronoatoms.htm

Today's spectrograph astronomers assume that the effect is not null.

It seems to me that today's astronomers are wrong because in physics are
still null result.
So I am looking for the result from communication with the spacecraft.
S*



Earth's rotation is about 465.1 m/s
Say the average frequency of visible light is 500THz

doppler shift is (Vr/C)*F = (465/ 3 * 10^8)*500 * 10^12 = 7.75 10^8Hz
So to see the shift you will need to be able to observe your light
frequency to an accuracy of about 0.00015%. Which would have been
impossible for Arago.

Of course the above figures are only true for light coming directly at
the observer ie on the horizon, so for other angles there is a Cos Theta
term to reduce the effect even more (to zero directly overhead).

Jeff