11/21/2005: Iridium flare

Elspode · 11-22-2005, 12:40 PM

Perhaps this was a rare coincidental double flash occurance? I mean, it *is* a single time exposure, as evidenced by the lack of a break in the star trails.

xoxoxoBruce · 11-22-2005, 03:09 PM

Quote:

The photo above showing two iridium flares was captured above Aachen, Germany (51°N, 6°E) on September 29, 2005.

Quote:

The dual flares shown above were less than one degree apart (approximately 40 seconds). At the time the picture was taken, Iridium satellite #8 (right) and satellite #51 were both positioned over the North Sea, some 2,600 km away (about 1,610 miles), nonetheless, the geometry of their orbital position with the Sun was just right to produce these parallel flares.

Location = 1600 miles north of Aachen, Germany (51°N, 6°E).
Separation = 40 seconds.

glatt · 11-22-2005, 03:40 PM

Quote:

Originally Posted by xoxoxoBruce

Separation = 40 seconds.

40 seconds or 40 arc seconds? 40 arc seconds is "less than one degree." A lot less.

Are they talking about time or about angles?

More importantly, why am I drawn back to this pointless discussion?

xoxoxoBruce · 11-22-2005, 04:43 PM

Because inquiring minds want to know.

Kingswood · 12-09-2005, 06:44 AM

Iridium satellites can be seen in pairs but it is rare.

Most Iridium satellites have similar orbital parameters so they are usually well separated. The Iridium satellites are groups of satellites spaced around the same orbit. A few Iridium satellites have orbits at a slightly different altitude. There used to be spare satellites in orbit at a different altitude, so if one satellite died there was a ready replacement already in orbit. Now I think that's no longer the case, but there are a few Iridium satellites that have different orbital periods to the rest. In either case, what happens is the lower satellite orbits faster than the higher one. Every now and again two satellites will pass each other. If you are lucky enough to be in the right spot it is possible to see twin flares.

I witnessed a twin Iridium flare about 3 or 4 years ago, after it was predicted on heavens-above.com. Two very bright satellites visible simultaneously is really an amazing sight.

11-22-2005, 12:40 PM	#1
Elspode When Do I Get Virtual Unreality? Join Date: Dec 2002 Location: Raytown, Missouri Posts: 12,719	Perhaps this was a rare coincidental double flash occurance? I mean, it is a single time exposure, as evidenced by the lack of a break in the star trails. __________________ "To those of you who are wearing ties, I think my dad would appreciate it if you took them off." - Robert Moog

11-22-2005, 04:43 PM	#4
xoxoxoBruce The future is unwritten Join Date: Oct 2002 Posts: 71,105	Because inquiring minds want to know. __________________ The descent of man ~ Nixon, Friedman, Reagan, Trump.

12-09-2005, 06:44 AM	#5
Kingswood Draco dormiens nunquam titillandus Join Date: Nov 2005 Location: Melbourne, Vic Posts: 316	Iridium satellites can be seen in pairs but it is rare. Most Iridium satellites have similar orbital parameters so they are usually well separated. The Iridium satellites are groups of satellites spaced around the same orbit. A few Iridium satellites have orbits at a slightly different altitude. There used to be spare satellites in orbit at a different altitude, so if one satellite died there was a ready replacement already in orbit. Now I think that's no longer the case, but there are a few Iridium satellites that have different orbital periods to the rest. In either case, what happens is the lower satellite orbits faster than the higher one. Every now and again two satellites will pass each other. If you are lucky enough to be in the right spot it is possible to see twin flares. I witnessed a twin Iridium flare about 3 or 4 years ago, after it was predicted on heavens-above.com. Two very bright satellites visible simultaneously is really an amazing sight.

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