Orpington Astronomical Society

Astronomy => Alerts! Questions? Discussions... => Topic started by: Mike on Nov 15, 2013, 22:12:03

Title: Satellite Identification
Post by: Mike on Nov 15, 2013, 22:12:03
Does anyone know a good way of identifying unknown satellites? We were looking through Petra's scope last night and Petra said she could see something flashing. I had a look and could see it too. We were looking at Albireo and it was 20:41 The object went from N to S very very slowly and flashed every 4 seconds. I reckon it was about Mag 8. The speed at which it moved at though was incredibly slow. It must have taken 3-4 minutes to move across the field of view of the 24mm eyepiece which is much slower than any satellite i've seen before.

Any ideas on how to try to identify it?

Title: Re: Satellite Identification
Post by: mickw on Nov 16, 2013, 08:46:47
Heavens Above ?

This is at my location -
http://www.heavens-above.com/AllSats.aspx (http://www.heavens-above.com/AllSats.aspx)

You'll need to change to your location etc.
Title: Re: Satellite Identification
Post by: RobertM on Nov 16, 2013, 09:56:31
If you have trouble finding it then I think I have.
Title: Re: Satellite Identification
Post by: Mike on Nov 16, 2013, 10:17:09
Found it, it was Molniya 1-63 a Russian communications satellite. I found it with Skysafari Plus.

It has an orbital period of 12 hours which will explain the very slow movement. Also many other people have reported observations on satobs.org of it flashing so this particular one must be spinning.
Title: Re: Satellite Identification
Post by: Mike on Nov 16, 2013, 10:56:35
Quote from: RobertM on Nov 16, 2013, 09:56:31
If you have trouble finding it then I think I have.

Is that what you found Robert?
Title: Re: Satellite Identification
Post by: RobertM on Nov 16, 2013, 11:16:02
Yes, that's the one.  It was at an altitude of 22,940 miles so that explains the very slow movement
Title: Re: Satellite Identification
Post by: Mac on Nov 16, 2013, 14:28:36
It cant be at that altitude, as that would put it in the Clarke belt, which would mean that it would be geostationary.

And clearly it was moving, so it would have to have been at a lower orbit.

http://en.wikipedia.org/wiki/Geostationary_orbit (http://en.wikipedia.org/wiki/Geostationary_orbit)

(http://upload.wikimedia.org/wikipedia/commons/b/b4/Comparison_satellite_navigation_orbits.svg)

Mac
Title: Re: Satellite Identification
Post by: MarkS on Nov 16, 2013, 16:57:12
Quote from: Mac
It cant be at that altitude, as that would put it in the Clarke belt, which would mean that it would be geostationary.

And clearly it was moving, so it would have to have been at a lower orbit.

Elliptical orbit?
Title: Re: Satellite Identification
Post by: Mac on Nov 16, 2013, 20:48:20
Could be, but then it would be crossing other orbital belts.

Mac.
Title: Re: Satellite Identification
Post by: JohnP on Nov 16, 2013, 21:18:39
Orbital data for this satellite shows Perigee 2307km & Apogee of 38071km so definitely not a circular orbit...
Title: Re: Satellite Identification
Post by: Rick on Nov 16, 2013, 21:28:30
Quote from: MarkS on Nov 16, 2013, 16:57:12Elliptical orbit?

Highly elliptical, according to this: http://en.wikipedia.org/wiki/Molniya_%28satellite%29
Title: Re: Satellite Identification
Post by: Mac on Nov 17, 2013, 10:02:39
Interesting.

Mac
Title: Re: Satellite Identification
Post by: RobertM on Nov 17, 2013, 12:27:14
The orbit is highly elliptical and at high inclination to the ecliptic, see Wikipedia on Molniya for more info.  Just because a satellite is at the same distance from earth as geostationary satellites doesn't mean it's in a geostationary orbit - in this case it's passing through that orbit on it's way in or out.  This group of satellites seem to have a period of about 12 hours.

Robert