Iridium

General physics and astronomy discussions not directly related to Celestia
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ElPelado
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Iridium

Post #1by ElPelado » 02.04.2004, 12:18

Yesterday I was at an Astronomy meeting(the topic was the five visible planets) and the man conducting the meeting said that it had a surprise for as. At ~16:37 GMT he said: look to the north in 10, 9, 8, 7, 6.... and we saw a star appear and the dissapear. I knew it had to be a satellite, but I didnt know what it was, till he explained. It was my first Iridium. I thougth that they are like the ISS, that you see crossing the sky, but it wasnt...
Really beautiful 8O
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Post #2by maxim » 02.04.2004, 16:46

Thomas Guilpain provides the set of Iridium satellites for Celestia here or directly from here

maxim

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Post #3by JackHiggins » 03.04.2004, 17:46

http://www.heavens-above.com

Fill in your location details, and you'll see all the visible iridium flares listed for your location, every night!

I haven't been out in ages, but the last time I was, I saw three that were brighter than mag -5 in 90 minutes
- Jack Higgins
Jack's Celestia Add-ons
And visit my Celestia Gallery too!

Evil Dr Ganymede
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Post #4by Evil Dr Ganymede » 03.04.2004, 22:22

Wait a minute. These are satellites that look briefly like really bright stars, and then disappear from view?

I wonder if that might explain my freakout moment a few months ago - I was walking back from the cinema at night, glanced up, noticed a really bright star in front of me. Looked down as I passed under a tree, and when I looked up again the bright star was gone, and there was no sign of it anywhere else in the sky!

Could that have been an iridium flare?

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Adirondack M
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Post #5by Adirondack » 03.04.2004, 23:38

Evil Dr Ganymede wrote:Could that have been an iridium flare?


If it was moving, you probably saw an iridium flare.
It becomes brighter and brighter, than fading way.

Iridium flares are visible even in bright daylight!!!

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Post #6by ElPelado » 10.04.2004, 12:03

IF wheter conditions are good tonight, I will be able to see two in 2 minutes, almost at the same position...
Az: 359?(N) Alt: 12?
Az: 359?(N) Alt: 14?
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Post #7by ElPelado » 10.04.2004, 22:59

I saw both, very nice. It was soooooo little time between both of them, and almost at the same place!
The first one was as bright as venus and the second one not so bright, but also beautifull
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Post #8by TERRIER » 11.04.2004, 10:47

Adirondack wrote:
Evil Dr Ganymede wrote:Could that have been an iridium flare?

If it was moving, you probably saw an iridium flare.
It becomes brighter and brighter, than fading way.

Iridium flares are visible even in bright daylight!!!


Wow, I wonder if this was an Iridium Flare that a few of us thought was a UFO when returning from a soccer match many years ago. A bright light suddenly appeared in the sky to the west, then gradually faded away. However, I don't remember it moving, it just seemed to hover.

The date was October 29th 1983.
Location was near Penistone, Yorkshire, and the time was around 5:30pm.
Any way of checking ?

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selden
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Post #9by selden » 11.04.2004, 11:21

The first Iridium communications satellite was launched in May of 1997, so you saw something else.

http://www.rod.sladen.org.uk/iridium_launch.htm
Selden

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Post #10by maxim » 11.04.2004, 12:17

In the rare situation that a falling star directly points at you, you might also watch such an effect, because you don't see it from the side but from the very front.

maxim

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Just saw my first Iridium flare

Post #11by bassrat » 14.04.2004, 02:41

I just saw my first Iridium flare tonight! Wow, very bright, quite impressive. It only last a few seconds and then I could it moving as it faded. It was a -5 and appeared in the sky exactly where and when the heavens-above web site had predicted. I look forward to seeing more of them. :D

Thank you ElPelado for making me aware of this phenomenon occuring nightly in our skies. And thank you JackHiggins for the link to heavens-above.com

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Post #12by ElPelado » 14.04.2004, 14:45

You are welcome!
BTW: I've been seeing at least one on every night, very impressive...
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Post #13by ElPelado » 21.04.2004, 17:07

Today I saw two more.
And at the morning, 7:22 am local time, there was one wit ha magnitude of -7, but it was cloudy so I couldnt see it :cry:
On the 25th I think there will be another daytime flare with magnitude of -7.3, and I hope there wont be clouds...
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Post #14by eburacum45 » 21.04.2004, 19:45

Saw one myself the other night; very strange and impressive.

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Post #15by granthutchison » 21.04.2004, 20:01

ElPelado wrote:Today I saw two more.
Hey, El Pelado:
If you keep giving us information like this, we'll be able to work out exactly where you live. :wink:

Grant

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Post #16by ElPelado » 22.04.2004, 00:16

:)
Do you mean because of the time?
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Post #17by Evil Dr Ganymede » 22.04.2004, 00:59

I don't quite get how the info on the Heavens Above site works....

Take a look here, for example - this says the azimuth is 253 degrees, and the map looks about right - I'll have to be looking to the WSW to see the flare, right?

Now look at this one - it says the azimuth is 349 degrees, but the map says I should look east?! So which one is right - the text or the map? Should I be looking just off north there, or east?

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Post #18by granthutchison » 22.04.2004, 09:34

ElPelado wrote:Do you mean because of the time?
Iridium flares are pretty directional, so the timing and visibility depend on your latitude and longitude. You give me a crop of flares you've seen, and I could in theory work backwards to derive your location.

Grant

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Post #19by Harry » 22.04.2004, 11:16

Evil Dr Ganymede wrote:Now look at this one - it says the azimuth is 349 degrees, but the map says I should look east?! So which one is right - the text or the map? Should I be looking just off north there, or east?

If I understand it correctly, the map only shows where the best place to look at the flare is (the "flare center"). If you would drive (or possibly swim) 20 km from your location in the direction given on the map you could see the flare with maximum brightness (-7 instead of -2). But in both cases you would have to look at 349° (~N) to see the flare.

Harald

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Post #20by Evil Dr Ganymede » 22.04.2004, 15:22

Harry wrote:
Evil Dr Ganymede wrote:Now look at this one - it says the azimuth is 349 degrees, but the map says I should look east?! So which one is right - the text or the map? Should I be looking just off north there, or east?
If I understand it correctly, the map only shows where the best place to look at the flare is (the "flare center"). If you would drive (or possibly swim) 20 km from your location in the direction given on the map you could see the flare with maximum brightness (-7 instead of -2). But in both cases you would have to look at 349° (~N) to see the flare.

Harald


OK, but in that case, if the flare centre is 20 km off to the east of me, why do I have to look north to see it?! If I'm right under the flare centre, shouldn't I have to be looking straight up since it'd be directly overhead?


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