A TRIPLE CONJUNCTION IN THE SUNSET SKY: On Oct. 31st, the crescent Moon passed by Jupiter, creating a beautiful Halloween conjunction in the evening sky over Europe. Most people noticed only the Moon and Jupiter. Peter Rosén of Stockholm, Sweden, noticed a third member of the conjunction: Ganymede.
“Ganymede is visible to the left of Jupiter,” says Rosén. “Coincidentally the 3 other Galilean satellites were in an extremely rare triple transit in front of Jupiter’s disc. Otherwise they would have been visible, too.”
Ganymede is a worthy addition to any conjunction. The giant moon of Jupiter is actually larger than the planet Mercury, and would dwarf our own Moon if the two were placed side by side. Did you miss the show? The Moon and Jupiter (and Ganymede) will meet up again on Nov. 28th. Mark your calendar!