Another "what in the heck was it" story
Posted 14 May 2013 - 07:47 PM
Since getting back into astronomy last year, I am amazed at how much stuff is floating around out there unnoticed, compared to just a few years ago.
Maybe Mulder was right
Posted 14 May 2013 - 08:00 PM
Posted 14 May 2013 - 09:25 PM
Posted 14 May 2013 - 09:49 PM
Posted 14 May 2013 - 10:05 PM
3 seconds to vault across the sky is awfully fast for a satellite. I'd say 30 seconds is far more reasonable and done far longer than that.
"One side to the other" as in one end of the eyepiece's FOV to the other, not the entire sky. I guess I should have been more specific.
Posted 14 May 2013 - 10:14 PM
What color was the flashing light? White? High-intensity anti collision aircraft strobes have a flash pattern of several seconds between flashes, with a series of very fast pulsing flashes (multiple per second) during the "main" flash. This makes the flashes much more noticable to the eye.
Posted 15 May 2013 - 08:37 AM
Posted 15 May 2013 - 09:56 AM
30 Seconds is a long time to cross the FOV of a 50* eyepiece, had to be going slow. A satellite would be there and gone hardly before you knew it.....
Posted 15 May 2013 - 12:34 PM
Posted 16 May 2013 - 10:57 AM
...were frequently spotted by amateurs in the Tennessee and Kentucky area back in the 50s and 60s.
... regions also famous for high-zoot hootch.
I see satellites semi-routinely, the slow-moving golden glow that crosses a half-degree slice of sky in one's EP over the course of a handful (or two) of seconds. Have *not* seen them flash strobes before, but that would be cool. If the strobe flashed morse-code for "eat-at-Joe's", that's be funny... if it flashed "Joe is now one of us" i'd be a bit unnerved...
I've also noticed, several times, a seriously weird effect-- while observing a DSO and/or its starfield in an undriven Dob, suddenly one "star" will be seen drifting slowly across the field. But as i watch it, it becomes apparent that this "drifting" "star" is not actually drifting, but it's the FIELD that is drifting! (as it normally does in an "undriven" scope ) The "star" is remaining stationary in the FoV!
A geosynchronous satellite!
These can be quite the mind-bender to stumble across in this manner. When seen in a "driven scope" (done this, too), it's not weird in the least- obviously & simply is a satellite.
Posted 16 May 2013 - 11:40 AM
Posted 16 May 2013 - 01:06 PM
Posted 16 May 2013 - 01:11 PM
Posted 16 May 2013 - 01:19 PM
Posted 16 May 2013 - 01:23 PM
Posted 16 May 2013 - 01:29 PM
Posted 16 May 2013 - 01:50 PM
Not always. There are many different types of orbits. To "sync" you just have to orbit the planet at the same rate of it's rotation. It's all about inclination. A geostationary orbit, from my understanding, is possible only within a certain area above the equator. Those satellites appear more near Earth’s ecliptic and do not appear to move very much.
Posted 16 May 2013 - 02:55 PM
Correct. Those are the ones that (essentially) don't appear to "move" in an undriven scope. As i hear it, there are frequently gaggles of them that share the same vicinity, sharing the same GEO-synchronous property... and for various GEO locations around the globe. I believe i've seen this once, where several "stars" could be seen "hovering" in formation as the rest of the sky rotated by in the scope's FoV.
Those satellites appear more near Earth’s ecliptic and do not appear to move very much.
Perhaps these are what're termed "geostationary"?
Posted 16 May 2013 - 03:43 PM
Posted 16 May 2013 - 04:38 PM
Anyway here is some short info on GEOS.
Since geostationary satellites remain over the same point on Earth, their orbits must have a period equal to the Earth's rotation on its axis = 23h56m. They also must go around the equator other wise they would appear to move North and South throughout the day and go in a circular orbit or this would appear to move East and West throughout the day. GEOS are in orbit around 35,000 km.
A geostationary satellite would be in an orbit of 0 degrees inclination, zero eccentricity and a mean motion of 1.002701 revolutions per day or a period of 1436 minutes per revolution. The Earth rotates once in about 23 hours and 56 minutes (1436 minutes); the remaining 4 minutes allow the Earth to rotate further, compensating for the apparent change in position of the Sun. This arises from the movement of the Earth in it's orbit about the Sun. In fact most geostationary satellites are really geosynchronous. Having mean motions between 0.9 to 1.1 revolutions per day they are allowed to drift across a box before corrections are made by on board thrusters.
Satellite observing is very fun, there is a lot of sites, app's and even programs to use with your goto scopes.
Posted 17 May 2013 - 11:25 AM
Posted 17 May 2013 - 12:18 PM
As for whether these would have a strobe effect? I don't know enough to be able to answer.
(as an aside) The planetarium software "Home Planet" can give a POV view from a satellite - it's fun tracking a Russian satellite in a Molniya orbit as it reaches perigee.