Author Topic: Parallel satellites arc across sky  (Read 3413 times)

Offline nasas6272

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Parallel satellites arc across sky
« on: 09/01/2010 07:40 PM »
Hey gang,

So I just heard today the recent excitement about the Chinese satellite rendevous (http://forum.nasaspaceflight.com/index.php?topic=21988.30).  Coincidentally, I had been snapping some time-lapse photos of the Perseid meteor showers during the early morning hours of 8/14, and happened to catch a pair of satellites tracing parallel paths across the sky very close to one another.  At the time my curiosity meter shot right up, but I didn't know what they might have been.  Upon hearing the news about the Chinese sats today, I thought perhaps that was what I caught in the photos.

So I started figurin'.  I got some archival elements for SJ-6F and SJ-12 from space-trak.org from 8/13, and plugged them into STSPLUS to run pass predictions for 8/14.  While the sats do pass over that area, it's  at the wrong time and in the opposite direction.

Now I'm wondering.  Did I make a mistake in my tracking simulation and these really are SJ-6F and SJ-12, or did I see something else?  The attached photo was shot at 03:43 am EDT on 8/14, from Eastern Maine (estimated Lat 44.847, Lon -67.159.)  The camera is looking due East, and the sats were traveling from North to South (right to left in this picture.)  The sky angle covered by the tracks in this 40 second exposure is about 14.6 degrees.

How can I figure out what these sats are? 

Thanks!
« Last Edit: 09/01/2010 08:11 PM by nasas6272 »

Offline Space Pete

Re: Parallel satellites arc across sky
« Reply #1 on: 09/01/2010 08:01 PM »
Hi, welcome to the forum! :)

I really can't comment on your particular case, but I have seen satellites in parallel a few times (just last night I saw one satellite travelling NE overtake another satellite travelling NE).
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Offline foltster

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Re: Parallel satellites arc across sky
« Reply #2 on: 09/01/2010 08:37 PM »
Based on http://www.heavens-above.com/allsats.asp?lat=44.847&lng=-67.159&alt=0&loc=maine&TZ=EST&Date=40404.4375&Mag=4.5&AM=T  it should be some combination of:

NOSS 3-4 (A)   3.7    03:10:01    35°    SW    03:13:07   72°    NW   03:20:01   10°    NE
NOSS 3-4 (C)   3.7    03:10:08    36°    SW    03:13:13   73°    NW   03:20:06   10°    NE
NOSS 2-3 (C)   4.3    03:11:27    40°    SW    03:13:42   83°    NW   03:20:14   10°    NE
NOSS 2-3 (E)   4.3    03:14:03    39°    SW    03:16:23   81°    NW   03:22:55   10°    NE

but heavens above is not the best way to track satellites....

Offline nasas6272

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Re: Parallel satellites arc across sky
« Reply #3 on: 09/02/2010 11:05 AM »
Thanks foltster, that's a great tool!  I found that by setting the limiting magnitude to 5.0 several more candidates were added to the list (they were quite dim.)

Offline Antares

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Re: Parallel satellites arc across sky
« Reply #4 on: 09/03/2010 07:46 PM »
Yeah, most low-magnitude formation fliers are spysats, especially the NOSS birds.
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

Offline Speedracer

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Re: Parallel satellites arc across sky
« Reply #5 on: 09/08/2010 06:43 PM »
Calsky is another site for sat-tracking I use.

It sounds like the NOSS sats are what you saw. I've seen three of them in formation years ago and it was the coolest thing. Their like a +6 magnitude so you either have to be in a location devoid of light pollution or using binoculars.
“Discovery is seeing what everybody has seen and thinking what nobody has thought”
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Offline Antares

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Re: Parallel satellites arc across sky
« Reply #6 on: 09/08/2010 10:38 PM »
I saw a trio around Monterey Bay once in the late 90s.  Limiting mag couldn't have been better than +4.
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

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