Jupiter Moons Io and Callisto Align for Mutual Occultation
Observers in the U.S. Midwest and farther west have a great opportunity this morning to watch one Galilean moon pass in front of another. Midwest and western regions can view a celestial alignment this morning as two of Jupiter’s Galilean moons cross paths.
The alignment takes place between approximately 5:39 A.M. and 5:44 A.M. CDT. For observers along the East Coast, bright morning twilight will make spotting the event challenging. Astronomers advise anyone attempting East Coast observations to put away optics several minutes before local sunrise.
Telescope Viewing Conditions in the Midwest
During the occultation window, Jupiter shines at magnitude –1.9, sitting roughly 36 degrees high in the eastern sky within the constellation Leo, positioned to the upper right of the star Regulus. Telescopes pointed at the gas giant around 5:30 A.M. CDT will reveal Ganymede positioned alone to the west of the planet. Europa sits close to Jupiter’s eastern side, while Callisto and Io appear on the western side farthest from the planet.
Observers watching the two outermost moons will see them close the distance and appear to merge through the eyepiece. Experienced astrophotographers are encouraged to capture the mutual event to record detailed imagery of the passage.
Viewing the Conjunction of Moon and Antares
Skywatchers without telescopes can look to the southwestern sky after sunset for a different celestial pairing. The Moon passes 0.4 degrees south of Antares at 5 P.M. EDT, lingering in the sky for roughly two hours before dropping below the horizon. The 19-percent-illuminated waxing crescent Moon rests just to the lower left of the red giant star Antares and near the third-magnitude star Tau Scorpii.
Frequently Asked Questions
When does the occultation of Callisto happen?
The occultation occurs between approximately 5:39 A.M. and 5:44 A.M. CDT, with Io passing directly in front of Callisto from our viewpoint on Earth.
What equipment is needed to see the Jupiter moon alignment?
A telescope is required to resolve the individual moons and watch Io and Callisto appear to merge.
Where is Jupiter located in the sky during the event?
Jupiter sits roughly 36 degrees high in the eastern sky in the constellation Leo, positioned to the upper right of the bright star Regulus at magnitude –1.9.