SETI Protected Antipode Circle at United Nations


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Profile Bruno Moretti IK2WQA
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Message 1007978 - Posted: 25 Jun 2010, 0:50:36 UTC
Last modified: 25 Jun 2010, 0:57:08 UTC




Crater Daedalus (80 km diameter) on the Farside of the Moon,
ideal site for a future radio telescope (or array) totally RFI-free.
Photo NASA Apollo 11 courtesy.

Claudio Maccone present PAC, the Protected Antipode Circle at United Nations



73 & clear skies from Bruno IK2WQA - brmoret_at_libero.it
FOAM13 Astronomical Observatory, Tradate (Italy)
Founder SETI@home Berkeley's Staff Friends Club
Founder SETI ITALIA Team G. Cocconi

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Message 1008153 - Posted: 25 Jun 2010, 14:18:55 UTC - in response to Message 1007978.

We've discussed using the "back side of the Moon" for a radio telescope but the shadow of the moon from earth would probably be more efficient and easier to use
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Message 1008188 - Posted: 25 Jun 2010, 16:39:25 UTC

The far side of the Moon or the Earth Moon L2 point are not totally RFI free even now. There are 3 satellites orbiting the Sun Earth L2 point and 2 more will be there within a few years. If you go out and look at a full moon some night, those satellites are out there about 10 times as far as the Moon and very nearly directly in line with it. Whatever communications they're sending to Earth are RFI on the Moon's far side.

I personally think an asteroid would be better. It would provide enough mass for a stable base and some portion of the construction materials, while having a low enough gravity field that the cost of landing those materials which would have to be supplied from Earth would be small. The distance from the Earth Moon system would mean only a small pointing area would be RFI prone, and that area would be moving relative to the distant stars. The very low gravity field would also allow a large structure with much less stress than even on the Moon. The chosen asteroid should have a suitable rotation rate to provide automatic scanning relative to its axis, a telescope would only need to drive its pointing in North - South declination to provide scanning of almost all the sky.

Joe

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Message 1008291 - Posted: 25 Jun 2010, 20:33:33 UTC - in response to Message 1008188.

the problem with an asteroid beyond actually getting the materials to the asteroid is the eccentric rotations, orbit and perpetual bombardment with smaller asteroids.
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Profile Bruno Moretti IK2WQA
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Message 1008444 - Posted: 26 Jun 2010, 1:31:05 UTC - in response to Message 1008188.

3 satellites orbiting the Sun Earth L2 point Joe


Yes, Joe, but...

Moon and his radio quiet cone on the Farside orbiting around Earth.
Sun Earth gravitational system L2 point are NOT Earth Moon gravitational system L2 point.




73 & clear skies from Bruno IK2WQA - brmoret_at_libero.it
FOAM13 Astronomical Observatory, Tradate (Italy)
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Message 1008514 - Posted: 26 Jun 2010, 5:13:28 UTC - in response to Message 1008444.

3 satellites orbiting the Sun Earth L2 point Joe

Yes, Joe, but...

Moon and his radio quiet cone on the Farside orbiting around Earth.
Sun Earth gravitational system L2 point are NOT Earth Moon gravitational system L2 point.

Exact alignment of the directions would only occur at the midpoint of a total Lunar eclipse, but any full moon would be close enough alignment to cause difficulty for an extremely sensitive radiotelescope. It needn't be a major problem, the radiotelescope would simply not try to observe at the affected frequencies during those periods every 28 days. But "totally RFI-free" doesn't apply today, and as more and more space development occurs the RFI will inevitably increase.
Joe

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