Caught some satellite pass today

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AndyG
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Re: Caught some satellite pass today

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That is so cool! Congratulations.
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Bruce D
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Re: Caught some satellite pass today

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I agree with Andy, that rocks Bill!
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Apollo XX
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Re: Caught some satellite pass today

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That is cool, but I'm a doubting Thomas on it being the ISS - too slow is the first thing I picked up on, then the spots change position as the video progresses. Maybe a few birds flying really high? Either that or the ISS has put the brakes on and now has Transformer capabilities! :lol:

Mike
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Re: Caught some satellite pass today

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The Globestar has much longer. rectangular panels- this looks more like the Boeing GPS III satellite

http://www.aviationnews.eu/2011/03/15/l ... ne/gpsiii/
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Re: Caught some satellite pass today

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Whatever it is, it makes sense that it's placed really high, thus appears relatively slow, and is spinning on its axis so would explain the movement. The ISS is what, 250 miles up? It crosses the solar disc in about a second or less depending on where it crosses it. Your object has an eight second transit time and is only crossing about 1/3 of the way up the disc. I'm no astrophysicist, so I have to ask if an object of a given mass is placed in the vacuum of space at the same height as an object with more or less mass, do they have the same orbital speed (aka: falling to earth)? http://www.physicsforums.com/showthread.php?t=217301 I guess any difference is not reasonably measurable, so the next question becomes is it a linear equation to calculate the orbital height based on the rough data we have, like in 250 x 8 = 2000 miles up? Probably too simple, but food for thought.

Mike M.
"The purpose of life is the investigation of the Sun, the Moon, and the heavens." - Anaxagoras
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Apollo XX
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Re: Caught some satellite pass today

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So if you were out doing your imaging around 9:35ish today, then this http://www.heavens-above.com/passdetail ... 919&type=A is what you caught. It's part of the West-Ford Project http://en.wikipedia.org/wiki/Project_West_Ford from the early 1960's. Interestingly, the orbital height fits the linear-equation proposal in my last post, where the ISS is at 400 kilometers and this is at about 3600k - roughly 9 times higher, and that fits the transit time we're seeing.

Mike M.
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AndyG
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Re: Caught some satellite pass today

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Apollo XX wrote:Whatever it is, it makes sense that it's placed really high, thus appears relatively slow, and is spinning on its axis so would explain the movement. The ISS is what, 250 miles up? It crosses the solar disc in about a second or less depending on where it crosses it. Your object has an eight second transit time and is only crossing about 1/3 of the way up the disc. I'm no astrophysicist, so I have to ask if an object of a given mass is placed in the vacuum of space at the same height as an object with more or less mass, do they have the same orbital speed (aka: falling to earth)? http://www.physicsforums.com/showthread.php?t=217301 I guess any difference is not reasonably measurable, so the next question becomes is it a linear equation to calculate the orbital height based on the rough data we have, like in 250 x 8 = 2000 miles up? Probably too simple, but food for thought.
Oh goody a physics problem :P

Kepler, my favorite astronomer, showed us (his 3rd law) that the square of the ratio of orbital periods is equal to the cube of the ratio of the semi-major axes of the elliptical orbits (mass does not come into it!). Assuming circular orbits:

If T1 = period of ISS
T2 = period of mystery satellite
R1 = radius of ISS orbit (= radius of earth + ISS altitude = 3959 mi + 230 mi = 4189 mi)
R2 = radius of satellite orbit, then

(T2/T1)^2 = (R2/R1)^3 or,

R2 = R1 (T2 / T1) ^ (2/3)

On my screen the diameter of the sun is 13 11/16" and the satellite traveled 10 7/8" in 8.5 seconds. From that, the transit time across the whole disk would have been 10.7 seconds. ( 8.5 sec x (13 11/16) / (10 7/8)). The ISS orbits in 92.89 minutes (5573 sec). Assuming the angular diameter of the sun is 0.5 deg, the ISS transit time is 0.5 deg / (360 deg / 5573 sec) = 7.7 seconds.

The ratio of the transit times is the same as the ratio of the full orbital periods, so T2 / T1 = 10.7 / 7.7 = 1.39, and

R2 = 4189 mi x (1.39) ^ (2/3) = 5216 mi

Altitude = (R2 - Radius_of_earth) = 5216 mi - 3959 mi = 1257 mi 8)
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Pete
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Re: Caught some satellite pass today

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Although Bill's object appears to have solar panels the images I've seen of the ISS transiting the sun show the ISS to be relatively larger than what Bill captured. Also, the ISS transit takes only about 1 second for a full transit, not the 7 seconds recorded on this off-center pass.

Hats off to Andy. His numbers appear to be in the ball park. For the apparent size imaged, and at that altitude, this is one big bird.

To add to the confusion, Cal Sky shows a double solar transit on the NH/MA border (lon=-72.005187° lat=42.785918°) at 09:34 and yet again at 16:01

My memory's not that good but I can't recall that any ASSNE member has captured the ISS. What time were these frames taken Bill?

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AndyG
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Re: Caught some satellite pass today

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AndyG wrote:The ISS orbits in 92.89 minutes (5573 sec). Assuming the angular diameter of the sun is 0.5 deg, the ISS transit time is 0.5 deg / (360 deg / 5573 sec) = 7.7 seconds.
Oops, I goofed there :oops: . The ISS transit time is way faster than that .... need to go back to the drawing board.

But assuming the ISS transit time is about 0.5 sec, then the satellite altitude would come out to be about 27,000 mi, right in the ballpark for a geostationary orbit of 26,200 mi.

But that makes the projected size too big, the satellite would have to be enormous, so something is wacky here. I say it is aliens.
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Apollo XX
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Re: Caught some satellite pass today

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AndyG wrote:
I say it is aliens.
And Alien Teenagers at that! Driving like idiots swapping places in space!!! What do they think this solar system is, a racetrack?

:lol:
"The purpose of life is the investigation of the Sun, the Moon, and the heavens." - Anaxagoras
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