ISS, Tiangong, Satellites Over Puna

[TomK]

I was actually lucky to see it - 30 years experience in the field helped! It was much fainter than expected, but there is a thin layer of cirrus above us right now which caused that, plus the low clouds didn't help. The passes tomorrow and Sunday should be a little easier. The only issue will be the clouds; the cirrus is forecast to be much thicker tomorrow night, so Sunday may turn out to be the best chance.

[Midnight Rambler]

quote:

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Originally posted by TomK

Roughly what time of night was this? The reason I ask is if it was something in low earth orbit (LEO), you would only be able to see if for an hour or two after sunset or before sunrise. If it was in the middle of the night, then it almost certainly wasn't something in orbit.

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It wasn't the middle of the night, but it was around 8:30. Maybe it was so faint because it was just catching the last light? I lost it completely just as it got close to the highest point of the arc.

[TomK]

Thank you, Midnight, that is very helpful. Given your description, I strongly suspect you saw a large piece of space debris that was tumbling, most probably an old rocket body. Everything seems to fit.

Firstly, it was "flashing" which as you mention, means it would be rotating or "tumbling" which is common for these objects. Secondly, its faintness is about what you might expect for such an object. Thirdly, given the approximate time you mention, the fact it disappeared as it got to its highest point is consistent with the type of low earth orbit rocket bodies tend to be in as they enter the Earth's shadow.

Orbiting rocket bodies are actually more common than you might think, so it's not as if this is a really unlikely explanation. To get some idea, have a look at this site which shows satellites, rocket bodies and large pieces of orbital debris in real time:

http://stuffin.space/

Finally, you may find this interesting. I suspect the reason you wrote "I could see some looking directly at it, but more consistently by looking just off to the side of the track" is that you inadvertently used a technique called "averted vision". The very center of your retina is not very sensitive in dark conditions whereas the area surrounding it is much more sensitive. Amateur astronomers often use averted vision to spot very faint objects. It takes practice, but, basically, you look slightly away from the object to see it. It takes time to perfect as obviously, your brain tells you to look directly at the object that's a little in your peripheral vision, but after a while, it's a great way to spot things you might not normally see.

[Midnight Rambler]

Interesting, I hadn't considered that! Yes, I knew about averted vision (though I didn't know the term for it), and was deliberately using it to try to track it.

[TomK]

I wrote:

"Sun April 23: Rises in the WNW at 19:53, heads ESE (passing above Betelgeuse, but closer this time) with the highest point at an elevation of 74 degrees above the horizon in the SSW at 19:57:24 before heading off towards Jupiter where again it will enter the shadow as it gets close to the planet.

Sky track: https://goo.gl/1UPr5N

There are also passes each weekday evening next week, but it's starting to get fainter then."

Tonight's pass was a washout, but there's still Sunday night for those interested. If that doesn't happen due to weather, I'll post the info for Monday, but after that it'll become more difficult to spot as it becomes fainter.

[TomK]

I'll post something late afternoon Monday if it looks as though the weather will cooperate.

[PaulW]

We should get a good flare when Cassini crashes into Saturn and ignites that gas giant.
Which gas? Hydrogen!

[TomK]

Talking about flares, there's a brightish Iridium flare occurring tomorrow evening (Thursday 27th April) at 20:09:40. This one should be easy to spot if the sky is clear. It will happen right next to a bright Jupiter in the ESE. The satellite will be moving from north to south if anyone wants to try and spot it before the flare.

[mermaid53]

Mahalo Tom! [] Will be on the lookout for it!

[TomK]

Mermaid - the flare will only last a few seconds so you'll need to be looking at Jupiter at the precise time! Incidentally, the flare should be about 12 times brighter than Jupiter from Kaloli Pt., so if you can find Jupiter, spotting the flare should be easy.

For those in Hilo, Keaau, Kurtistown and Hawaiian Acres, it will be even brighter.