Jupiter - longitude systems

[teleskopjo]

I would like to know how are longitude systems measured on Jupiter please since all features we see are constantly in motion?

On the Earth the 0 degree longitude line through Greenwich is the reference.. .but on a cloud system how could you establish a 0 degree line? Thanks!

[ronin]

Don't think you can have a reference point in the same manner as we have.

Our reference is based on what is an astronomical observation, without being able to view the sky clearly that would seem to make it impossible to follow the same principal.

For some time there was "2" Meridians in use, Greenwich and Paris I believe. And eariler I suspect even more.

If I recall it was when the US decided to use the Greenwich option that it became the dominent one.

[teleskopjo]

I do not quite get it .. On what basis are the Jupiter system 1 and 2 longitude references issued ie. where is the 0 ? 

[Stu]

This might help....

http://www.projectpluto.com/grs_form.htm

[teleskopjo]

thanks