Iridium Flare or Sizable Fireball

[cpumasterwv]

Hi all, really quick question.

I was watching ISS fly over Mountain Home, Idaho on Saturday at 2200L. Shortly their after, my friend pointed out a sizable flare up in the sky. It went from below naked eye to brighter than Venus in under a minute, then faded out. During this time it stayed almost at zenith , maybe moved 5 degrees from SW to NE. I checked on Stellarium, and can't find any other Satellites that would have made a pass like that. My thinking is that it was a Spy Sat, or a somewhat sizeable piece of galatic flotsom. Opinions and observations appreciated.

 

[cpumasterwv]

Wow, those are some loud crickets...

 

[CalliArcale]

I checked with Heavens Above. While it won't go back more than 48 hours on Iridium flare predictions, it doesn't appear that any Iridium satellites were due to pass over you anyway, so you can pretty much rule that out. There were a whole lot of satellites (mostly dim) passing by, but they didn't hang around the zenith; they all went horizon to horizon. So like you, I can't find a satellite (spy or otherwise; Heavens Above is pretty comprehensive for anything big enough to actually see) that could explain it.

My money is on "fireball" -- you may have witness a meteor coming in almost directly inwards. Those do not appear to move much during their entry, because you're seeing the path almost head-on. Very very cool!

 

[MeteorWayne]

I've been out of town, so that's why I didnt reply sooner.

The fireball idea is a non-starter..it lasted far too long. Fireballs last a few seconds at best...maybe 30 seconds for an earth grazer (which would travel across the whole sky, not be basically stationary)
H-A Iridium page (and yes you can check weeks ahead or behind Calli use the "Prev" or "Next" links). The Iridiums listed in that time frame were much lower elevation. However, that only includes the listed ones, which are the in-service Iridums. There are others; spare and defunct ones that have the same ability to flare, but the flares can't be predicted since the precise alignment of an in-service one is required to make accurate predictions of such a small spot on the earth's surface.

I have seen many flares from these other Iridiums. Once you've seen enough flares from these sats, they are impossible to mistake, and no other satellite produces the huge change in brightness that they do. With an uncontrolled one, they can last longer is the craft is rotating. That would be my best guess for what you saw.

BTW, under a dark sky, the Iridiums are visible even when not flaring, about mag +4.5 at times. I often see a whole plane pass by every 9 minutes when meteor observing...some will even flare to mag +3 or +2, which of course are not listed on the H-A flare page...it only shows flares 0 mag or brighter.

A number of other satellites of course flash and flare as well, but there's nothing like an Iridium, and to me, that's what you described.

MW

 

[MeteorWayne]

Just 2 minutes ago I saw one of those unpredicted Iridium flares, close to the zenith, not far from Vega. It made Vega (3rd brightest star in the N Hemisphere) look dim by comparison. At least mag -5.
MW

 

[cpumasterwv]

Sweet, thanks for the help guys!