which moon is it?

[eriksters]

So my dad recently bought me my first scope (skywatcher 200mm dob) and when I looked at jupiter on Wednesday I saw a small dot on one of the light bands but I had no idea which one is it.

My question is:

How do you know if it is a shadow or the moon it self and how to know which one is it?

Also is there any way how to tell with stellarium?

[JamesF]

The moons are fairly bright and not always easy to pick out when they're in front of Jupiter.  The shadow is quite obviously a dark spot in my experience.  Often you'll see the moon to one side and the shadow on the planet at the same time.

In Stellarium you can skip to a given date and time and zoom in on Jupiter to get a look at what was happening at that time.  You may need to configure it to allow for the speed of light as what we see here on Earth actually happened twenty to thirty minutes previously on Jupiter.

James

[Paul73]

Glad that the scope is showing you some good stuff.

Download the "Jupiter's Moons" app from Sky & Telescope. It is free and tells you exactly what you are looking at!

re the Moon or Shadow question. The shadows are black and well defined. The moons are light coloured and quite hard to pick up against Jupiter's disk.

Paul

[JamesF]

Download the "Jupiter's Moons" app from Sky & Telescope. It is free and tells you exactly what you are looking at!

You reminded me of their Javascript application that showed various bits of data about the Galilean Moons, so I found it in my bookmarks and discovered  that you now have to register to get access to it!  I'll be deleting that one then

James

[eriksters]

Allright, thanks a lot guys.

I found the javascript thing on their website.

Turns out it was the shadow of Io .

[eriksters]

*europa (accidentally wrote 9:00 instead of 21:00)

[Vox45]

There is a neat little software that can help you with all kind of information on Jupiter.

Get it for free here

Hope that helps

[John]

I've found this link recently. Not sure how accurate it is but I'll check it out when next observing the giant planet:

http://www.shallowsky.com/jupiter/

Clicking "animate" is quite fun

[Hyperion76]

good app for the outer planets and their moons gas giants really easy to use and you can even program your scope type in

[Hyperion76]

in case that is not clear its called Gas giants