Hubble Captures Rare Triple-Moon Conjunction

Jupiter — January 24, 2015

Firing off a string of snapshots like a sports photographer at a NASCAR race, NASA's Hubble Space Telescope captured a rare look at three of Jupiter's largest moons parading across the banded face of the gas-giant planet: Europa, Callisto, and Io. These so-called Galilean...

Jupiter Moon Transit, January 24, 2015 (06:28 UT)

Three moons and their shadows parade across Jupiter at the start of the event at 06:28 UT on January 24, 2015. From left to right the moons Callisto and Io are above Jupiter's cloud tops. The shadows from Europa (not seen in the image), Callisto, and Io are strung out from left...

Jupiter Moon Transit, January 24, 2015 (07:10 UT)

Three moons and their shadows parade across Jupiter near the end of the event at 07:10 UT on January 24, 2015. Europa has entered the frame at lower left. Slower-moving Callisto is above and to the right of Europa. Fastest-moving Io is approaching the eastern limb of the planet....

Compass and Scale Image of Jupiter Moon Transit

During the observations of the Jovian triple-moon conjunction on January 24, 2015, Hubble also captured the smaller moons Amalthea and Thebe and their shadows traversing the cloud-covered face of Jupiter.

Jupiter Moon Transit, January 24, 2015 (06:28 UT) – Annotated

Three moons and their shadows parade across Jupiter at 06:28 UT on January 24, 2015. From left to right the moons Callisto and Io are above Jupiter's cloud tops. The shadows from Europa (not seen in the image), Callisto, and Io are strung out from left to right.

Jupiter Moon Transit, January 24, 2015 (07:10 UT) – Annotated

Three moons and their shadows parade across Jupiter near the end of the event at 07:10 UT on January 24, 2015. Europa has entered the frame at lower left. Slower-moving Callisto is above and to the right of Europa. Fastest-moving Io is approaching the eastern limb of the planet....

Geometry of Rare Triple-Moon Conjunction at Jupiter

This simulation illustrates the orbits and positions of Jupiter's four largest moons on January 24, 2015, during a rare triple-moon conjunction where the Hubble observations captured three of Jupiter's largest moons parading across the banded face of the gas-giant planet:...