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View Full Version : Ever have a Satellite pass infront of your Telescope? Q?


Phlosphr
02-20-2003, 10:16 AM
I was just wondering. I have a 10 inch Dobsonian (homemade) and the other night whilst looking at the darkside of the moon, something very briefly passed infront of the scope. I am not saying it was a satellite, but it is certainly unexplained. No it wasn't my wifes hand either. And it was a brilliantly clear night out, and it was not a plane. Could it have been a satellite?
Anyone else have a similar experience?

Q.E.D.
02-20-2003, 10:20 AM
Sure. I've seen (and tracked) satellites using binoculars. Some satellites rotate and can appear to "blink" on and off, others remain steady.

Phlosphr
02-20-2003, 10:36 AM
My scope is BIG!! and the resolution is very good, this object was not in focus either. Obviously becuase I was focused on the moon...I wish I could track them, I never really thought it could be done. Can you see everything on them? Camera's, lens, solar paneling etc..etc...-whatever else you'd find on one?

Q.E.D.
02-20-2003, 10:45 AM
I don't think you could see much in the way of detail on them. At least not the ones in low orbit. In order to see anything like that, you'd have to have really high magnification, but the field of view would be so small you couldn't keep it in view for very long, if at all. Those things move fast! you might be able to make out the general shape though. I've never really tried.

bup
02-20-2003, 10:50 AM
You saw it moving? Then my guess is satellite too.

If, instead, you saw a brief flash, then it's possible you saw the result of a meteor striking the dark side of the moon.

Ike Witt
02-20-2003, 10:52 AM
???? Phlosphr, how were you looking at the dark side of the moon? The dark side of the moon is, by defintion, not facing the earth.

scr4
02-20-2003, 10:53 AM
I've seen many satellites through telescopes, and they look just like moving stars. If you are focused on an astronomical object (including the moon) you should see it as a focused point of light. If it wasn't focused then it was probably something else, but I can't tell from your description. How bright, how large and how fast was the object?

You can't resolve any features on a satellite with amateur telescopes. Your telescope might have enough resolution to make out the solar panels on the ISS, but at that magnification you won't be able to track the ISS without a computerized mount. This page (http://satobs.org/telescope.html) shows some photos of satellites taken with such computerized telescopes.

Squink
02-20-2003, 10:55 AM
Got a look at satellite through a 16" scope pointed at the Ring nebula. It showed up as a fast moving point. It was probably one of those spy satellites in near polar orbit. Tracked by eyeball for a minute or two after it passed from the scope's field.

Q.E.D.
02-20-2003, 11:02 AM
Originally posted by adam yax
???? Phlosphr, how were you looking at the dark side of the moon? The dark side of the moon is, by defintion, not facing the earth.
No. The dark side of the moon is the side not illuminated by sunlight. Look at a half moon sometime. You can clearly see that half is being lit up by the sun, and the other half is not. You're thinking of the far side of the moon, the side that always faces away from Earth.

Phlosphr
02-20-2003, 11:07 AM
Adam - au contraire, when the moon is half or 3/4 you can look at the line that deliniates light from dark on the moon. that line has probably 200 miles or so of dark gray area on the serface of the moon, where you can see shadows and shapes and such. My scope has wonderful resolution and craters and mountains, valleys etc..etc... show up quite nicely...

Ike Witt
02-20-2003, 11:27 AM
Okay, that makes sense. I had always heard of the dark side of the moon in context of being the far side of the moon. I didn't realize it related to the parts you couldn't see during the waxing and waning.

Phlosphr
02-20-2003, 11:38 AM
What I like so much about looking at the dark side of the moon, is that the shadow you are seeing on the moon is the earth itself... The big peice of mud you are standing on... When you step aside and really think about the shadow of the earth on our moon, it is very humbling, at least to me. Makes one really think how truly small we are

scr4
02-20-2003, 11:39 AM
Originally posted by Phlosphr
What I like so much about looking at the dark side of the moon, is that the shadow you are seeing on the moon is the earth itself...
You mean a lunar eclipse? That's the only time the earth casts a shadow on the moon.

Floater
02-20-2003, 11:41 AM
Originally posted by Phlosphr
What I like so much about looking at the dark side of the moon, is that the shadow you are seeing on the moon is the earth itself...
Well, at lunar eclipses you can se the shadow of the Earth. Not at other times.

Phlosphr
02-20-2003, 11:49 AM
Excuse me? When you look at that crescent shaped moon, what is causing the large circular shadow on it, making it look crescent shaped? Is that not the shadow of the earth on the surface of the sun?

Phlosphr
02-20-2003, 11:51 AM
Ahem....Moon I mean... :smack:

why oh why didn't I preview

bernse
02-20-2003, 11:54 AM
Your seeing the non-illuminated part of the moon, thats all.

Koxinga
02-20-2003, 12:01 PM
Lest the magic be completely taken away, Phlosphr, I believe that you can still see dimly reflected Earth light on the dark side of the moon--that's why it still shows up relatively clearly.

Or is somebody going to shoot this idea down as well?

Koxinga
02-20-2003, 12:02 PM
And I know that Earth light is reflected sunlight--I just think it's kind of neat that the light bounces from the Earth to the Moon and back again.

Phlosphr
02-20-2003, 12:05 PM
the non-illuminated part of the moon? It's not the shadow of the earth on the surface of the moon. Good God, and for all those years.....I thought....Damn!!!

Phlosphr
02-20-2003, 12:06 PM
Thanks for telling me before Mrs.Phlosphr and I had kids..

bup
02-20-2003, 12:10 PM
Right, but as Doghouse points out, if you can see anything on the dark side of the moon, it's due to Earthshine.

mambozzy
02-20-2003, 12:15 PM
Right. What causes night on Earth, Phlosphr, the moon's shadow? No, the moon, like the Earth, is rotating and thus, while one side is in sunlight, the other side is in twilight. It's simple physics, man.
-Oz

mambozzy
02-20-2003, 12:18 PM
Wow, I missed that one by a solid 14 minutes. That's what I get for putting SDMB second.

Phlosphr
02-20-2003, 12:47 PM
the moon, like the Earth, is rotating and thus, while one side is in sunlight, the other side is in twilight.

This I understand. I was having a bit of trouble with the whole crescent moon thing....

Drum God
02-20-2003, 02:15 PM
Okay then, back to artificial satellites...

As a plot point in many Star Trek episodes, the good ship Enterprise arrives in orbit around some industrial world. Sometimes it's even "Earth in the past." Kirk (or Picard) and Company then conduct their clandestine operations on or around the planet and no one is aware of their presence.

Now, supposing a ship the size of any of the various Enterprises were to really orbit our planet, would we notice it? Would average people walking around on Earth wonder what that thing was or would it be too small to notice or stand out? In First Contact, LaForge uses a telescope to point out the Enterprise-E to a skeptical Zephram Cochran. Could a typical hobbyists telescope identify the Enterprise? Or would it take fancy military or scientific equipment.

Ankh_Too
02-20-2003, 02:21 PM
Originally posted by Phlosphr
This I understand. I was having a bit of trouble with the whole crescent moon thing....

Try this website (http://www.astro.umd.edu/education/astro/moon/phases.html). The illustration should make it much easier to follow.

Derleth
02-20-2003, 02:22 PM
Originally posted by adam yax
???? Phlosphr, how were you looking at the dark side of the moon? The dark side of the moon is, by defintion, not facing the earth. There's no such thing as the dark side of the moon. Matter of fact, it's all dark.

:p

Llama Llogophile
02-20-2003, 02:41 PM
I've had this happen several times while using my 4" refractor.

Once at a star party, I saw something zoom through the field. I thought it was me, but a moment later someone else who was observing the same faint galaxy as me said, "Hey, did you see that?"

No details - it just looked like a fast moving star.

About the Star Trek: First Contact thing. I'm guessing that you MIGHT be able to see detail in that situation, but only because the Enterprise is supposed to be massive. Nearly a mile long, as I recall.

RickJay
02-20-2003, 02:47 PM
As a matter of fact, Phlosphr, when there IS a lunar eclipse - the Earth's shadow on the Moon - it doesn't make the Moon dark. It makes it a reddish color.

There will be a total lunar eclipse on May 16 and against on November 8 of this year.

Shiva
02-20-2003, 02:51 PM
From NASA's J-Pass website
http://liftoff.msfc.nasa.gov/RealTime/JPass/20/

Ever see a light moving across the night sky and wonder if it's an airplane or a spacecraft (or even a UFO)? Many people enjoy satellite watching as a fun hobby, and you can join them using J-Pass. Using your location and the latest available tracking data, J-Pass can predict the times a satellite will pass overhead, and even give you a chart showing the path of the craft through your sky.

DrDeth
02-20-2003, 03:02 PM
In my childhood, they sent up into orbit two HUGE balloons that were to have signals bounced off them (Hey NASA geeks- what were those called?). They were clearly visable by the naked eye.

Hanna
02-20-2003, 03:04 PM
On summer nights I often sit in the backyard and stare up at the sky. I see a lot of satellites naked eye. At first it looks like a star, but it is moving. They don't go fast, like a meteor, but slowly move across the sky. Really neat.

Mangetout
02-20-2003, 03:12 PM
I hope nobody will mind the slight hijack, but it's too close a question to warrant opening another thread:

Are satellites in orbit visible to the naked eye?

One very dark, clear night, I went out to the countryside with some friends and we were far away from light pollution and smog; after our eyes had fully adjusted, we could see and incredible number of stars, but also some tiny specks that were moving; might these have been satellites or would they be something else?

rowrrbazzle
02-20-2003, 03:16 PM
www.heavens-above.com can give you the same information as NASA. You should also be able to specify a date in the near past and look for a likely candidate for your lunar transit.

This page has an AVI of a lunar transit: http://home.no.net/jonbent/Moon.html (third from the bottom). It requires the DIVX codec, though, so I couldn't play it.

I've never seen a satellite cross the field while I was looking through a scope, but on one occasion I saw a meteor flash by.

DrDeth: those were the ECHO satellites. I remember seeing them, too.

Mangetout: absolutely yes. You can even visit the NASA site or Heavens Above to find out what they were. You can also very easily see bright reflections from the Iridium satellites just about anywhere.

bup
02-20-2003, 03:17 PM
If they weren't blinking, they were probably satellites.

Q.E.D.
02-20-2003, 03:19 PM
Wow, a question answered before it was even asked. This is a helluva message board! :D

Q.E.D.
02-20-2003, 03:22 PM
Satellites can blink too. Some of the are rotating and will appear to blink as different sides reflect the sunlight differently.

DrDeth
02-20-2003, 04:35 PM
rowrrbazzle- Yep, "Echo", thanks.

And, Yes- some other satelites, but the sky has to be clear, and you have to look sharp. But not EchoII, that was real obvious, even in smoggy LA.

Chronos
02-20-2003, 04:40 PM
The Enterprise would most certainly be visible. Under the proper conditions, the Space Station is brighter even than Venus, and the Enterprise is a lot bigger than the ISS. So far as I know, she also doesn't have any features to make her difficult to detect (yes, I know that the Enterprise doesn't have a cloaking device, but you could also just paint her black, which nobody seems to even think of). Details, though, would require a scope. It is possible to get distinguishable pictures of the Space Station or the Shuttle with an amateur scope (that is to say, detailed enough to recognize what it is), so Geordi showing Cochraine in a telescope is probably plausible, depending on what sort of scope Cochraine had.

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