NASA - Hubble snapped these mind-blowing pictures of Jupiter's extremely rare triple moon transit

[mordin86]

http://www.businessinsider.com/three-largest-moons-of-jupiter-just-did-something-incredibly-rare-2015-2

[Tommygun]

Nice, the Jupiter system seems to often have something interesting going on.

Even if all you have is a small telescope set up, you can spend hours staring at it and tracking it's moons.

[Bill Phil]

Yeah...

The Galilean moons are pretty fast... Callisto has an orbit of ~17 DAYs.

[SuperFastJellyfish]

Amazing! Thanks for posting this.

Edit: I've observed Jupiter and his moons more than anything else in the sky(even our beloved Moon). It has a hold over me, and I'm kicking myself for not knowing about this event. >< Too busy recently, I guess.

Edited February 8, 2015 by SuperFastJellyfish
rant

[magnemoe]

Nice, fun story is that back in 18-19th century Jupiter moon transits was used to synchronize clocks on remote bases. This was important as ships could get their clocks updated.

[AngelLestat]

I dont understand the moon´s shadows XD

Can someone explain me the perspective please?

[How2FoldSoup]

As you can see from this excellent photo made in paint, Earth is lower is in a different spot in its orbit than jupiter, so we see it form a different angle. This means that it's moons' shadows are not seen from a straight line with respect to us, but from the Sun. Hope this helps you see..if not, mayhaps someone else can explain better.

edit: not to scale

Edited February 8, 2015 by How2FoldSoup

[The Yellow Dart]

Amazing! Thanks for posting this.

Edit: I've observed Jupiter and his moons more than anything else in the sky(even our beloved Moon). It has a hold over me, and I'm kicking myself for not knowing about this event. >< Too busy recently, I guess.

I've been using this list so far this year to keep from missing astronomical events, it has worked well so far!

http://www.universetoday.com/116461/the-top-101-astronomical-events-to-watch-for-in-2015/

[AngelLestat]

Thanks How2foldsoup for bother, but if the earth is at that angle, then we would see only the half of jupiter in light.

I was searching, in that link of yellow dart is explained:

The shadows are from different moons.

[Tommygun]

Callisto's shadow was confusing me.

It's orbit is a lot higher than the other two, so Callisto's shadow can be much farther away from it.

[Newt]

Thanks How2foldsoup for bother, but if the earth is at that angle, then we would see only the half of jupiter in light.

Jupiter is nearly at opposition (very near to Earth), How2FoldSoup was probably making an exaggerated illustration to better demonstrate the point.

[How2FoldSoup]

Jupiter is nearly at opposition (very near to Earth), How2FoldSoup was probably making an exaggerated illustration to better demonstrate the point.

This was exactly what I was trying to do. Exaggerating things generally makes them easier to see. Plus I even put the "not to scale" disclaimer!

[AngelLestat]

ok dont worry, thanks you any way how2foldsoup.

[moronwrocket]

Actually, it's a *five* moon transit. In this re-aligned version, you can just see Amalthea and Thebe in the bottom left of the white central belt in the first picture, and at the top right just below Callisto's shadow in the second picture.

http://www.unmannedspaceflight.com/index.php?showtopic=7971&view=findpost&p=217793

One other thing to notice is that the sharpness of the shadows are caused by the distance from Jupiter. Io's is sharpest, followed by Europa and then Callisto.

[PakledHostage]

Jupiter is nearly at opposition (very near to Earth), How2FoldSoup was probably making an exaggerated illustration to better demonstrate the point.

Here's a view of how Jupiter and the inner planets were oriented at the time of the transit, according to the Mobile Observatory app on my phone (time is GMT):