4 moons across jupiter

Hi,

I was thinking about fourrier transforms last night (I only had one pint btw).

Later looking at the almnacs of where Jupiters moons are and when I noticed that in 2d all the moons form sine waves, and you could sum the sine waves... If you could compute this in 3d then there might be a time when all moons would be directly in front of jupiter. Granted there is probably an easier way to compute this

Anyway I trawled a few sites today looking for information on when to see all moons in front of jupiter at the same time and didnt see any references. So how often if at all can you see all 4 moons in front of jupiter. If you cant how do you go about proving it?

Cheers,
~Al

Dunno about the courier transforms, Al, butt here's an easier way. There is a freeware program called JupSat that will show you the positions. You can run it in real time or speed it up to animate it. You can download it (or at least you used to be able to) from Sky & Tel's web site at

www.skypub.com/

D

Gentlemen,

This is something I looked into about 18 months ago. Unfortunately this is not possible for two reasons: (1) one of the moons (Callipso?) usually is at an orbit which puts it above Jupiter when viewed from earth thus making a transit against the Jovian surface impossible for most of the time (its orbit does tilt and there are opportunities to have it transit Jupiter), (2) due to resonance between the four primary satellites, we will never have an opportunity to watch all four satellites transit the surface at the same time when viewed from earth.

Anthony.

I have Jean Meeus' books "Mathematical Astronomy Morsels" and "More Mathematical Astronomy Morsels" and will try and get a chance look into the technical stuff on shadow transits later.

however, I've pointed out to Ron Baalke (Space Calendar website) and Fred Schaaf that there will be a rare triple-shadow transit of three of the Jovian moons on March 28th this year. We won't see it from here as Jupiter will have set. The next occasion is 2013 October 12. Ron has put up a link to www.projectpluto.com/interest.htm#Three_shadows
It's also mentioned in Sky-High 2004 (sorry, can't resist the plug!!!)

also rare is Jupiter without the four Galilean moons visible. The next opportunity is 2008 May 22. I last saw this is August 1997 so that gives an idea of the rarity!

have a good weekend folk!

John Flannery SDAS

Hi John,

Thanks for the link to Project Pluto and the triple shadow mutual event list. It is a very interesting list which deserves being borne in mind! Unfortunately, being at UT+2, I will also be missing the 2004 event and must wait for the 2013 opportunity (assuming Jupiter is still up in the sky for me).

Anyway, there is always something new in the sky!

Anthony.