The jovian moons therefore should appear 30% brighter than usual. Adding to this, all moons will be lined up on the planet's western (preceding) side and Ganymede (III), the biggest and brightest of them, is at it's maximum elongation.
|Simulation of the Jupiter system for Jan 5, 2014, 22:14 CET (21:14 UTC)|
Opposition is exactly at 21:11 UTC. Jupiter is 4.2 AU (630 million km) from Earth at opposition, -2.7mag bright, and appears 46.76" in diameter in a telescope. It is visible as a bright star all night in the constellation Gemini.
I personally am interested in any (positive or negative) results, and Bernd is as well. You're invited to report them as a comment, if you like, or mail them to Bernd.
Update: I took this picture (0,5s @1600ASA, f/5,6, 200m telephoto lens) almost exactly at opposition. The moons (Io, Europa, Ganymede and Callisto, as well as 44Gem) are easy in binoculars (10x50), but I could not see any of them with unaided eyes. Maybe one needs better (darker) skies..?