Satellite spotting

[BOAC]

The sky last night over the part of Sussex I live in was AMAZINGLY clear around 2300. Whilst escorting the dogs on their night-time 'constitutionals' I saw lots of satellites over a 20 minute period. All but one were south to north, one north to south. I did not see one west to east. I was under the impression that polar orbits were less common than equatorial? Does anyone here know about satellite orbits and how many there are on polar paths?

[HEATHROW DIRECTOR]

I'm not a genius on these matters but can thoroughly recommend
www.heavens-above.com where you can get all manner of info about satellites.

[swp53]

Go to the NASA website and look for viewing the ISS for example. You can enter your location and get a list of what satellites will be visible at what times and where to look.
Hope this helps.
Regards,
Steve.

[BOAC]

Ta HD - registered there now. I now know I have not been imagining 'flashes' in the sky

[PPRuNe Pop]

Here is another one which you can set up but also allows you watch for the next passing of the Station and Shuttle.

If you expand the whole site there is inumerable opportunities for satellite watching.

http://science.nasa.gov/Realtime/jtr.../JTrack3d.html


Turn the world any which way to get the EXACT orbit.

[Conan the Librarian]

HD has the answer! Heavens above is a truly magnificent resource for anoraks, teachers and those with an interest.

The location database is huge and the passes are to the second, as predicted. None of the hassle of updating epoch/TLE files every few days, as required with most of the PC based Sat pred progs.

Brillo - and free!


Whilst we are at it - I was there a few mins before finding this thread and looking for ISS/Shuttle passes, when I found this, which although off topic is a neat idea....

http://www.heavensabovefireworks.com/


Conan

[None of the above]

BOAC

Polar orbits are used by weather sats (NOAA etc) and those on surveys of some sort eg Landsat.
The advantage of a polar orbit is, given that the globe rotates within the plane of the orbit, that the entire surface of the earth may be photographed every 24hrs. The ISS, Shuttle etc orbit at 50Deg to the equator.
Now, it's a long time since I dabbled in this, so it's a case of E&OE but I think that orbital inclination is directly related to the latitude of the launch site and/or the size of the payload.
Sorry if the previous para is a bit vague but perhaps someone else can quote chapter and verse.

N o t a

Edited to add: http://www.centennialofflight.gov/es...RBIT/DI154.htm

[BOAC]

Another good crop last night and it looks as if the Perseids are with us.

[Whispering Giant]

Spent many a enjoyable evening last year spotting sattelites whizzing across the sky whilst visiting my parent's in spain - especially as they live in the back of beyond so dont get any light pollution.

good fun - especially on the way back from the local tavern.

[AIRWAY]

They are spying on us the ETs

Saw one, during my holiday to Portugal not so long ago, i have to admit it was fascinating.

[BOAC]

good fun - especially on the way back from the local tavern

- and easier too, being on your back

[Conan the Librarian]

Last year but one, I took the Heavens above prediction and ground track for ISS with me to the pub, in order to prove that the Space Station was indeed visible. I took this girly outside five or six minutes ahead to acclimatise her night vision and we started to look up.Within two mins the whole pub had emptied and were looking up too. A minute after that and the pub across the road was emptying fast as well. Even traffic was slowing to a halt.

Bang on time, over the western horizon came the space station, much to the relief no doubt, of the publicans and Interbrew. Magnificent sight. Since then, Three or four of those watchers have acquired either telescopes or binoculars, so it must have made some impact...

Conan

[treadigraph]

As PPRuNe Pop knows, I frequently walk home fairly long distances from the pub at night and yet have only ever seen TWO satellites, both in the last couple of years, despite keeping an eye out - it's a bloody swiz!

To be fair, I do live in a an area of severe light pollution but I would have expected to see a few more over the years, particularly whne coming back along one or two less well lit and remoter routes.

Actually, to correct meself, I also saw Skylab in '73...

Not much luck with the meteors either, except for that wonderful Leonides shower two or three Novembers ago. You know, the one when it was going to be overcast...

I am always amazed at how much air traffic there is late at night...

[DubTrub]

One of the other features of Heavens Above is the ability to predict the time, location and path of Iridium satellites.

These have very flat, polished aluminium faces which reflect the sun and appear as a rapidly growing, then diminishing light as they pass, and can be as bright as aircraft landing lights.

The site offers 24-hour and 7-day forecasts.

[wiggy]

None of the above.

You are right, essentially Orbital inclination cannot be less than the latitude of the launch site unless you are prepared to use a lot of fuel to change the plane of the orbit during launch / at some subsequent stage of "flight".

Re Payload, launching "to the East" makes maximum use of the Earths "spin" - once you launch into higher inclinations you reduce the amount of velocity given to your launcher by the Earth ( in extremis if you go for a retrograde launch - To the West; you are intially using fuel cancelling out the Earth's spin before you start imparting orbital velocity). The Shuttle used to be launched mainly into Low inclination orbits, giving max payload - the decision to now always launch into a 52 degree orbit to match that of the ISS has reduced the shuttles ability to lift heavy payloads to orbit.

[Onan the Clumsy]

All but one were south to north, one north to south

If you went to Mission Control, you'd probably see the one going North to South was controlled by an older gentleman wearing a trilby.

I took this girly outside five or six minutes ahead to acclimatise her night vision

riiiiight

[Hilico]

Ah yes treadigraph, I saw Skylab make its pass over the UK in '73 as well. I had the telescope all set up and everything, and it went over at about ten times the speed of your typical airliner - never got a bead on it.

[BOAC]

Time to dig this thread up again!

2 nights running now I have seen high and random flashes almost overhead, and apparently geostationary, at around 2200A. Sometimes 1 bright, 1 dim, sometimes 2 the same.

Any ideas? Mrs Boac says they are taking flash pictures....................

[Mycroft]

I remember a few years ago (heard about Heavens above here) going outside to watch an Iridium flash and was surprised how many other satellites were visible.
Unfortunately for treadigraph you do realy need to stand staring at the sky just waiting for something to move, also if you have been out with Pop you are probably going home too late (remember you are looking at refections of the Sun; too late and the sun is too far below the horizon).
Most satellites in an equatorial orbit would either be loo low for good observation from UK (ie Hubble never visible from here) or in geostationary orbits and essentially invisible (ie not very bright and not moving). One of the things to check up on is Iridium Flash, when the antennas reflect the sun straight at you for 5 seconds they are the brightest point object in the sky (the solar panels are even larger/brighter but unfortunately not predictable)

[treadigraph]

also if you have been out with Pop you are probably going home too late (remember you are looking at refections of the Sun; too late and the sun is too far below the horizon).

Actually did see another one the other night - out in a friend's garden drinking 9.5% Devonshire cider and we all saw one heading in a north easterly direction... don't think it was the drink... Reasonably dark out there which does help.

Like to see one of these iridium flashes...