Satellites turning on and off

[watersblue]

Tonight, I noticed a satellite (I think) appear, and then it went 'off' quickly. The on time was perhaps a tenth of a second, off for maybe 5 seconds. Was this really some sort of satellite? It was travelling from South to North. After a while, the flashes became dim and faded away.

[watersblue]

By the way, this happened about 6 or 7 times before disappearing.

[Steve Ward]

Aircraft navigation lights . . .

[ronin]

Tumbling satellite ?

[ramstar]

Currently on my jollies in Central France - wonderful clear skies around midnight and where's my Dob -back home! Got 10x50 bins so still amazing to just stare and be amazed.

Seeing 3 or 4 lights moving across the sky in different directions - not planes I think but satellites?

[JamesF]

I saw loads of satellites last night. No idea why last night should have been particularly busy, but they just seemed to be all over the place.

James

[ramstar]

I'm around 30 miles west of Limoges and never, never have I seen skies like the last 2 nights! Why can't they be like this at home?

[watersblue]

Tumbling satellite ?

That's the impression I sort of had. I wondered if it was spinning and catching the sun every now and then.

[watersblue]

I saw loads of satellites last night. No idea why last night should have been particularly busy, but they just seemed to be all over the place.

James

Perhaps we aren't used to these clear skies. I'm trying to make the most of it taking photos, but I'm getting very knackered now due to lack of sleep.

[JamesF]

I'm feeling a little frayed myself after several 2am+ mornings Forecast is for clear again this evening though, so it looks like another late one...

James

[watersblue]

I'm feeling a little frayed myself after several 2am+ mornings Forecast is for clear again this evening though, so it looks like another late one...

James

Heh! There's a bit of a breeze where I am this evening, so that rules out pictures. I might get the dob out instead. I noticed a massive amounts of stars through the binos when looking at the central star of Cygnus, so might have a better look.

[Sp@ce_d]

Tonight, I noticed a satellite (I think) appear, and then it went 'off' quickly. The on time was perhaps a tenth of a second, off for maybe 5 seconds. Was this really some sort of satellite? It was travelling from South to North. After a while, the flashes became dim and faded away.

Probably an iridium satellite

http://en.m.wikipedia.org/wiki/Iridium_satellite_constellation

[JamesF]

You will do. Cygnus is bang in the middle of the Milky Way:

http://www.tanstaafl.co.uk/wp-content/uploads/2012/07/cygnus-display-1.png

Not by best image, and it's fairly large, but it gives you the idea. The three bright stars are the "summer triangle": Vega at the bottom, Sadr (the central star of Cygnus, upper right) and Altair on the far left.

James

[watersblue]

You will do. Cygnus is bang in the middle of the Milky Way:

http://www.tanstaafl...s-display-1.png

Not by best image, and it's fairly large, but it gives you the idea. The three bright stars are the "summer triangle": Vega at the bottom, Sadr (the central star of Cygnus, upper right) and Altair on the far left.

James

That is ridiculous! Brilliant photo. I assume this is taken through the camera lens?

[JamesF]

Yes, that was with the 450D and the kit 18-55mm lens.

James

[watersblue]

Probably an iridium satellite

http://en.m.wikipedi...e_constellation

I've seen quite a few of these flares. However, they seem to flare once; this one was repeating over and over- do any Iridium satellites do this?

[umadog]

I've seen quite a few of these flares. However, they seem to flare once; this one was repeating over and over- do any Iridium satellites do this?

Yes, they flare once. I too am not aware of blinking Iridiums. Repeatedly blinking would likely be a different sort of satellite.

You're more likely to see satellites at this time of year because the sun never gets far below the horizon. Consequently, all that stuff flying about above your head is more likely to be in sunlight and so capable of reflecting substantial light back to Earth.

[Mr Bond]

I always assumed on seeing these, that it was the solar energy panels catching the Sun as they spin. They are doing this so that there can be less problems if one were to fail. The others would still get exposure to light.

Yours is faster than I've seen but essentially the same I think.

[watersblue]

I always assumed on seeing these, that it was the solar energy panels catching the Sun as they spin. They are doing this so that there can be less problems if one were to fail. The others would still get exposure to light.

Yours is faster than I've seen but essentially the same I think.

okay, thanks.

[laser_jock99]

I saw loads of satellites last night. No idea why last night should have been particularly busy, but they just seemed to be all over the place.

James

Probably due the time of year- like the noctilucient clouds they are more likely to be in sunlight than in shadow at that altitude?

[umadog]

I always assumed on seeing these, that it was the solar energy panels catching the Sun as they spin. They are doing this so that there can be less problems if one were to fail. The others would still get exposure to light.

I don't think it's that. The panels can be arranged such that all of them are catching the sun whenever it's up: think of solar panels on a south-facing roof. This is the most efficient way of doing things. Some satellites are spun, however, to use the gyroscope effect as a means of stabilisation. With such satellites, the solar panels may be less efficient since they may not not always pointing towards the sun.

The brightening you see isn't only due to solar panels. For instance, Iridium flares are caused by sunlight reflecting off an antenna: http://en.wikipedia.org/wiki/Satellite_flare

Very rapid flashing is likely to be due to something more compact that can spin faster: http://www.satobs.org/tumble/tumbleintro.html

[JamesF]

Probably due the time of year- like the noctilucient clouds they are more likely to be in sunlight than in shadow at that altitude?

I think you're probably right. And I don't think I've had so many observing days around midsummer before.

James

[todd8137]

I would not worry i love counting them note in the time and roughly where they was then ,have a look on stellarium to see if amcan see which they were

pat

[Tim]

I have a picture demonstrating a satellite blinking across the sky at regular periods I think, and then being 'off' for a period before reflecting again, obtained when I spent an hour tracking and filming the QE2 asteroid.

I'll post it up tonight sometime in the lounge to see what members make of it.

Thanks

[glowjet]

I'm feeling a little frayed myself after several 2am+ mornings Forecast is for clear again this evening though, so it looks like another late one...

James

This is the trouble James, we are not used to having so much settled weather on the trot, we get the odd clear night among a wealth of cloudy ones, then all of a sudden we get a string of clear nights coming along one after the other, just like London buses. All I can say is enjoy it while you can