ISS, Tiangong, Satellites Over Puna

[Loretta]

Saw it......very cool!!!

[HereOnThePrimalEdge]

That was fantastic! Incredibly bright, even so near the moon. It stayed visible for a little while after the flash, first fading in intensity, then getting brighter again for a few seconds, although nowhere near the brightness of the flash, until finally fading away.

Tom, if you know exactly where to look before the flash, would it be visible for any length of time then as well?

You could never convince a monkey to give you a banana by promising him limitless bananas after death in monkey heaven.

[TomK]

Saw it as well, really nice. I'm glad others got to see it as well, especially those for which it was the first time!

HOTPE, that's a good question, and have to say, I don't know. In theory, it depends if the satellite is brighter than magnitude ~6 which is the faintest we can see on a dark night. If it were that faint, or even a magnitude or two brighter, you would need a dark sky to see it and would need to be looking in the exact spot to stand a chance.

I'll try and do a little research and find out how bright these things are when their panels aren't directing sunlight at us but are still out of the Earth's shadow. Thanks, great question!

From wiki:

https://en.wikipedia.org/wiki/File:Iridi...opeia.webm

[PaulW]

It was great! Thanks

[TomK]

HOTPE - it turns out the info is in Heavens Above. This is just the info for the satellite that produced the flare earlier this evening:

http://www.heavens-above.com/SatInfo.aspx?satid=27375&

Intrinsic brightness (Magnitude): 6.2
Maximum brightness (Magnitude) 5.1 (perigee, when it's closest to the Earth).

It'll be slightly different for each of the Iridium satellites, but assuming this is typical, the brightness is close to the limit the naked eye can see on a dark night. So, yes, you might be able to see it before the flare, but you'd have to know exactly where to look and be quite lucky to spot it.

I think the only way to guarantee you could see it is to use a fairly decent camera, on a tripod, taking video in the general area. I will look to see if the numbers above are typical or not though, but would be surprised if they aren't.

I'm assuming you're not an advanced amateur astronomer who's able to use RA/dec or Alt/Az plus tracking rates. If you are, I should be able to post that info for the next bright flare.

ETA: I did a quick spot-check of various Iridium satellites. The numbers above are typical. That's not a surprise as the Iridium satellites are all in similar orbits.

[Loretta]

I saw it before the flare. I was looking in the general area (and also had on my really good distance glasses) and said to my husband..."look that satellite is moving quickly" and just as he looked up and followed my pointing finger, it flared. It then dimmed and then flared again. After that it dimmed and I could no longer follow it. Is this what you mean?

[HereOnThePrimalEdge]

the brightness is close to the limit the naked eye can see... you might be able to see it before the flare... use RA/dec or Alt/Az plus tracking rates
...
I saw it before the flare... Is this what you mean?

TomK & Loretta,
Yes, thanks!
That should make future viewings more interesting with the additional challenge of spotting the Iridium satellite's orbital path a few seconds or so before the flash. Something to look forward to next time.

Clear night skies everyone.

You could never convince a monkey to give you a banana by promising him limitless bananas after death in monkey heaven.

[TomK]

There's another extremely bright flare predicted for the evening of April 27th. There are one or two brightish flares before that, but this is a good one if you want to see if you can spot the satellite prior to the flare, as it'll happen right next to Jupiter.

It's a little too far in the future to provide a really precise prediction right now, so will provide details nearer the time, but the sky will be nice and dark as it'll be a new moon. Assuming clear skies, it should be a perfect opportunity!

[TomK]

Incidentally, if you want a challenge, but not one quite as difficult as spotting an Iridium satellite before it flares, the Hubble Space Telescope (HST) has some brightish passes over the island on the evenings of April 21, 22 and 23. It won't be anywhere near as bright as the ISS or the recent Iridium flares, but a nice opportunity to say you've seen one of the greatest scientific instruments of all time with the naked eye.

Please let me know if you're interested and I'll post details nearer the time.

[PaulW]

I'm interested! But I'll probably be elsewhere then. Which is the best website, Heavens Above?