Thread: Radio Astronomy
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Old November 7th 11, 06:43 PM posted to rec.radio.amateur.antenna
Szczepan Bialek Szczepan Bialek is offline
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Default Radio Astronomy


" napisał w wiadomości ...
On Mon, 07 Nov 2011 10:14:14 +0100, Szczepan Bialek rearranged some
electrons to say:

"The first observations of cosmic radio emission were made by the
American engineer Karl G. Jansky in 1932, while studying thunderstorm
radio disturbances at a frequency of 20.5 MHz (14.6 m). He discovered
radio emission of unknown origin, which varied within a 24-hour period.
Later he identified the source of this radiation to be in the direction
of the centre of our Galaxy. From:
http://encyclozine.com/science/astronomy/radio

I understand that the frequency "varied within a 24-hour period". It is
the "diurnal effect".
And what about the 365 days period (annual effect)?
S*


It is not the frequency that changed, but the intensity. And not a 24
hour period, but 23 hours, 56 minutes, thus proving that the noise was
not generated or varied by the earth's rotation.

http://www.enotes.com/karl-jansky-reference/karl-jansky


Yes. "His" transmitter "produced" many frequencies. But Karl G. Jansky was
the pioneer in Radio Astronomy.

Now are the spacecrafts. They use the two frequencies.
I have found the link:
http://chaos.swarthmore.edu/courses/...er_Anomaly.pdf

""It is also possible to infer the position in the sky of a
spacecraft from the Doppler data. This is accomplished by

examining the diurnal variation imparted to the Doppler shift

by the Earth's rotation. As the ground station rotates underneath

a spacecraft, the Doppler shift is modulated by a sinusoid."


Probably in this paper is also the answer for my question: "And what about
the 365 days period (annual effect)?

Unfortunately I am not an expert in radio. Do you know the answer?
S*