Jupiter Question

[Tsan (Kerrin)]

Tonight I managed to get out for a look, before the weather rolls back in. Took a look at Jupiter and noticed a black spot on the planet. I could only see 3 moons, could the black spot have been a shadow on the planet from one of the moons?

Total newb question, but wanted to check with the brains trust to make sure it is what I think.

[ausastronomer (John Bambury)]

Originally Posted by Tsan

Tonight I managed to get out for a look, before the weather rolls back in. Took a look at Jupiter and noticed a black spot on the planet. I could only see 3 moons, could the black spot have been a shadow on the planet from one of the moons?

Total newb question, but wanted to check with the brains trust to make sure it is what I think.

Hi,

Io the innermost of the Galilean moons was in transit which was followed by its shadow, which is what you saw.

Cheers
John B

[astronobob (Bob)]

Sounds most likely a moon shadow Kerrin !

Here is a 'freeware' program that when you set your time, location etc, this will show what is currently happening with Jupiter, its Red Spot, and all four Galilean moons with transits and shadow transits.
You can go Forward or Back in time - minutes, hours, days, weeks, years and it will show exactly what going on at that time - very good for planning visual & imaging sessions

http://www.astrosurf.com/rondi/jupiter/#

[Tsan (Kerrin)]

Thanks guys, I figured that is what it was, but wanted to confirm it. Now to plan the GRS viewing!

[Rick Parrott]

Another great Jupiter & Moons free app (for iPhone, not sure for other) is called Gas Giants. This also shows Saturn, Uranus and Neptune.

[Tsan (Kerrin)]

Thanks Rick, I'll check it out.