Jupiter’s four large moons (Io, Europa, Ganymede, and Callisto) are hard to miss, and a favorite telescopic target of backyard observers. They are commonly referred to as the Galilean Moon’s due to the fact that they were discovered by Galileo Galilei over 400 years ago.

It just so happens that on the night of January 23-24th (Friday night into Saturday morning) these four large moons will be putting on a must see show. A triple shadow transit!

The video above from NASA outlines that transits and events as they unfold on the night of January 23rd.  I have listed them below giving the Central Standard times.

9:11 p.m. CST Callisto’s shadow appears on Jupiter.

10:35 p.m. CST Io’ shadow appears on Jupiter.

11:41 p.m. CST Eclipse – Io enters Callisto’s shadow (watch for Io to dim and brighten over a twenty minute period).

12:27 a.m. CST Europa’s shadow appears Jupiter.

Triple shadow transit occurs for 25 minutes from 12:27 a.m. CST to 12:52 a.m. Another triple shadow transit like this will not happen again for 17 yeas in 2032.

Above is an image of the planet Jupiter taken on April 25, 2004. I took this image through a 10″ telescope. If you look close you can see a small dark spot on the planet. That is the shadow of Jupiter’s moon Ganymede and it is very much what you can expect to see when looking through a telescope at this transit however there will be two bonus shadows!

So where do you find Jupiter in the sky? It’ll be hard to miss at -2.3 magnitude and will be visible between Leo and Cancer above the eastern horizon.

So grab a telescope, get some coffee or hot chocolate, dress warmly or hug a friend, and enjoy the Galilean moons as their shadows dance across the face of the king of the planets.