Space station

[stuart noble]

Watched The International Space Station last night. Seemed to go right over my house :-)

A much misused word but "awesome" is the only way to describe it

[Brian Gaff]

Well its supposed to be de orbitted in ten years, less if Russia pulls out.

Seems such a waste since no replacement is anywhere near coming to fruition. Brian

[Chris Hogg]

Please, what's an 'iridium flare'? I've Googled for it, and although there's a lot of stuff mentioning it, I can't immediately see an explanation of what it actually is, other than it doesn't seem to have anything to do with the element iridium.

[JimK]

/Please, what's an 'iridium flare'? I've Googled for it/q.....

Really?

'Iridium flare definition'

Jim K

[Paul Herber]

[Martin Brown]

Some passes are brighter than others but -3 is typical. If you want to see something really awesome you need to catch a much rarer Iridium flare where the corner of a solar panel array concentrates light onto a narrow track on the ground. They can get up to -8 or brighter.

In normal money that is about 100x brighter than the ISS.

Does predictions for ISS, Iridium flares and other bright satellites (dim ones too). You shouldn't have long to wait there are plenty of them whizzing past silently at dusk and dawn.

[Chris Hogg]

OK. Got there. Iridium is the name adopted by a communications company. It has nothing to do with the element Iridium. I didn't know that. The several articles I looked at weren't immediately explanatory and assumed that knowledge.

[Andy Burns]

Iridium is a constellation of LEO scatterlites, used by phobiles for people on boatses, up mountains and doing polar expeditions etc.

They have flat panel antennae that are angled towards Earth a bit like someone doing a "W00t" \o/

When the sun glances off them at the right angle relative to where you are standing you get a few seconds worth of flare from them, supposedly visible by the naked eye.

[Chris Hogg]

Good explanation. Thanks.

[Bod]

Iridium Flare and comet 17P/Holmes. Satellite flare (also known as satellite glint) is the phenomenon caused by the reflective surfaces on satellites (such as antennas or solar panels) reflecting sunlight directly onto the Earth below and appearing as a brief, bright "flare".

[stuart noble]

I've checked out a couple of flares, but couldn't see anything. If they're rare, I suppose that's not surprising. Last night the ISS seemed like the brightest thing in the sky, but I wasn't looking at anything else. If the flares are x100 I might need dark glasses!

[Dave Liquorice]

Get some low power optical instrument (binoculars) on it and you should be able to make out the shape.

The first really bright satellite I saw was MIR, very bright and fairly fast moving spot of light. WTF was that "UFO"?

Compared to visible ISS passes Iridium flares are two a penny.

Not quite they have a fixed flat plate antennas (door sized according to the Wikipedia Satellite Flare article) and these reflect sun light directly onto the ground.

Iridium flares can be so bright that they are daytime visible. Heavens above will give those, but you have to tell it your location fairly accurately.

Clear night without too much light pollution and around 1 to 2 hours after sunset watch the sky for a few minutes and you should spot at least one if three or four satelites. Not all are fuctional devices.

Twinkle twinkle, little star How I wonder what you are Up above the sky so high Like a diamond in the sky

Twinkle twinkle, little star I've just found out what you are A lump of rusting rocket case A rubbish tip - in outer space.

(Spike Milligan)

[Dave Liquorice]

satellites

The ground track of the glint isn't very wide just a few miles, you have to tell Heavens above your position fairly accurately (lat and long from phones GPS, nearest town may well not be good enough and will throw off the timing). The flares don't last long, couple of seconds and aren't big, streak of light about the width of three fingers at arms length. Looking at the right bit of sky, altitude (up/down) and azimuth (around, compass like) for a minute or two before/after the predicted time should net you them.

Curiously I've just looked to see what Iridium flares are about for here and I have a few with "Distance to Flare Centre" measured in

100's of Km, presumably these are ones just glancing the surface of the earth?

[Jethro_uk]

I suspect some of the "shooting stars" I have seen over the years may have been flares ...

[tim.....]

Wot, A little white spot moving across the sky is "awesome"

You need to get out more

tim

[Clive Page]

Almost nothing to do with the element. But I think the original plan was for the number of satellites to be the same as the atomic number of iridium, i.e. the same as the number of electrons orbiting around a non-ionised atom of iridium.

I don't know, and can't be bothered to check, whether they eventually launched that number.

[stuart noble]

I was out. Well, out in the street anyway

[Dave Liquorice]

Maybe but flares are quite slow and short compared to most meteors. Flares don't leave a trail, meteors do but it can be short lived.

Looks as if it's going to be clear, might remember to go out and watch the ISS around 2032.

[ARW]

The site also used to give visual passes of the tool box some woman in space dropped:-)

Iridium flares are an excellent way to introduce children into astronomy and make it interesting - could you find a better way to start a Cub or Beaver astronomy badge challenge other than the view of an Iridium flare? - of course only the person helping with the badge knows exactly where and when the flare will happen (you have a 2 seconds max to see it).

[Graham.]

The first satellites I saw were Echo I & Echo II in the 1960s.

Just passive orbiting metallised balloons, but satellites nonetheless.

Their UK visibility predictions were published in the weather column of the Telegraph IIRC.