Curious as to what I saw tonight

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Curious as to what I saw tonight

Postby graeme » Tue Aug 23, 2016 10:44 pm

I’ve got a 6” reflector with equatorial mount. I live near Cambridge UK. Tonight at about 22:30 I was looking at what I think was Arcturus (I’m new to this!) and as I adjusted it into the centre of the eyepiece using the eq mount knobs I noticed a dot of light like a star moving in the opposite direction to the way I turned the knobs and far faster than the stars were moving.

My first thought was that it was some kind of aberration, but it was quite clearly there - leaving the telescope stationary the dot of light appeared to be moving and eventually it would move out of the field of view, but I could bring it back into view. Likewise I could take it out of the field of view and it didn’t appear anywhere else where I pointed the scope. I also thought that its movement might be an optical illusion and that it was stationary and the stars were moving due to earth's rotation.

Assuming it’s not a speck of dirt or my imagination can anyone suggest what it was? I was wondering geostationary satellite - but reflecting the sun from that far out and visible in a small scope? Sounds a bit of a stretch.
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Re: Curious as to what I saw tonight

Postby Aratus » Wed Aug 24, 2016 8:52 pm

Actually a 6" reflector can just about see a geostationary satellite. In a telescope aligned to the stars a geostationary satellite will slowly move out of the field of view. They will be very faint though.

Quite often the light from a fairly distant satellite or piece of rocket will slowly drift across the view through a telescope. It needn't be as far out as a geostationary satellite but it would be further out than something in low earth orbit.
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Re: Curious as to what I saw tonight

Postby The Man with the Corrugated Iron Roof » Thu Aug 25, 2016 9:45 pm

Seconded! Definitely a satellite.
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Re: Curious as to what I saw tonight

Postby david48 » Fri Oct 07, 2016 4:46 pm

Or a UFO
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Re: Curious as to what I saw tonight

Postby Aratus » Fri Oct 07, 2016 5:04 pm

Certainly a 'flying object' and 'unidentified'! :D If you mean an extra-terrestrial spacecraft then that would depend on whether you believe that vessels of that kind operate around the earth. That is more to do with instinct, hope and faith, I think, rather than scientific evidence. Not that I think that instinct, hope and faith are without value; far from it; it is just that I wouldn't want to build a scientific explanation on them. :)
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Re: Curious as to what I saw tonight

Postby Supercooper » Sun Oct 09, 2016 11:09 am

Or a reflection in the eyepiece. I had an eyepiece which produced another moon for Jupiter which moved when Jupiter did only the other way! Internal reflection is another possibility.
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Re: Curious as to what I saw tonight

Postby david48 » Sun Oct 09, 2016 4:12 pm

Aratus wrote:Certainly a 'flying object' and 'unidentified'! :D If you mean an extra-terrestrial spacecraft then that would depend on whether you believe that vessels of that kind operate around the earth. That is more to do with instinct, hope and faith, I think, rather than scientific evidence. Not that I think that instinct, hope and faith are without value; far from it; it is just that I wouldn't want to build a scientific explanation on them. :)


Just think what kind of "scientific explanation" our remote descendants might make of geostationary satellites, in the far future. After our present civilisation has collapsed owing to global warming, or global nuclear war, or population explosion, or whatever.

A new civilisation has arisen. Say in 100,000 years. And the people of it, are turning their newly re-invented telescopes to the sky. To make sense of it. They see the stars, wheeling about the Earth in a constant daily and yearly cycle.

They also see the planets, whose movements are irregular, but can eventually be sussed out by a future Kepler, and explained by a new Newton.

But what will the new people make of the old geostationary satellites. Those satellites will still be up in the sky. Even a 100,000 years from now. Decay from Clarke Orbit will last at least that long.

And when they're spotted, won't they cause merry hell with astronomy? Because they stay fixed in the sky, not moving. Seemingly defying any attempt at scientific explanation.

Won't they be a cause of frustration to our remote descendants, and might even cause a loss of confidence in the scientific method. Which might result in the failure of future civilisation to advance?
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Re: Curious as to what I saw tonight

Postby david48 » Sun Oct 09, 2016 4:56 pm

Supercooper wrote:Or a reflection in the eyepiece. I had an eyepiece which produced another moon for Jupiter which moved when Jupiter did only the other way! Internal reflection is another possibility.


Yes, internal reflections can be a problem. Especially when looking at very bright extended objects, like the Moon.

I've seen ghostly images of the Moon, floating around the edge of the field of view. But they didn't look real. Too pale, and easily dismissed as illusion.

But I've never seen a ghost image of a star-like point, such as a moon of Jupiter.

Obviously I wouldn't want to cast doubt on your observation. But it would seem to me, that if an eyepiece produced any illusory duplicate moon of Jupiter, then it should do the same for all 4 Galilean moons. So the eyepiece should've shown 8 illusory moons. Did it do that?

(I'm thinking here, that your're referring to the 4 main Galilean moons, and their star-like images in a small low-mag telescope - have I got that right?)
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Re: Curious as to what I saw tonight

Postby Aratus » Sun Oct 09, 2016 11:10 pm

david48 wrote:Just think what kind of "scientific explanation" our remote descendants might make of geostationary satellites, in the far future. After our present civilisation has collapsed owing to global warming, or global nuclear war, or population explosion, or whatever.

A new civilisation has arisen. Say in 100,000 years. And the people of it, are turning their newly re-invented telescopes to the sky. To make sense of it. They see the stars, wheeling about the Earth in a constant daily and yearly cycle.

They also see the planets, whose movements are irregular, but can eventually be sussed out by a future Kepler, and explained by a new Newton.

But what will the new people make of the old geostationary satellites. Those satellites will still be up in the sky. Even a 100,000 years from now. Decay from Clarke Orbit will last at least that long.

And when they're spotted, won't they cause merry hell with astronomy? Because they stay fixed in the sky, not moving. Seemingly defying any attempt at scientific explanation.

Won't they be a cause of frustration to our remote descendants, and might even cause a loss of confidence in the scientific method. Which might result in the failure of future civilisation to advance?

Actually I think the opposite would be true. In your scenario, a re-born civilisation might well observe artificial satellites in various orbits around the earth. Astronomers with a similar understanding as Kepler would come to the conclusion that they were objects in orbit around the earth since they would obey the same natural laws as an object like the moon. In fact having several such objects and measuring their distances and speeds would do a lot to help secure the scientific relationship between the two. The equivalent of Kepler's 3rd law might well have been realised much earlier.

However, to return to real world momentarily, :D The existance of artificial satellites, and lens flaring etc are in no doubt, and I think those explanations should be given first refusal before embarking on contemplating extra-terrestrial visitors as an explanation. :geek:
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Re: Curious as to what I saw tonight

Postby david48 » Mon Oct 10, 2016 5:10 pm

Thanks Aratus. I don't really believe in extra-terrestrial visitors to Earth, any more than you do!

Because, such ET's would long ago have conquered the Earth. And incorporated us into a minor province of their Galactic Empire. Or destroyed us, during a tremendous Galactic war between the silicon-based Dendi, and the protoplasm-based, but unspeakable worm-like Troxxt.

The only mild point I was making is this: if our civilisation completely collapses, future observers, in thousands of years' time, when they look at the night-sky, will see our ancient satellites in the sky.

Those satellites will look like stars. And if all knowledge of stellar astronomy has been lost, they will be interpreted as stars. Which is likely to confuse the new people who are trying to understand them. I think that's not unreasonable?
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