Titan darkens Saturn in rare shadow transit on Aug. 19: Here's how to see it

A simulation of the gas giant Saturn fully illuminated by direct sunlight. The planet's sweeping rings are positioned almost edge on to the observer, and a dark circular shadow is visible on the banded cloud surface above the ring line.

Grab your telescope and aim it at Saturn in the early morning hours of Aug. 19 to see Titan's colossal shadow sweep across the majestic gas giant's cloud tops.

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(Image credit: Jason Parnell-Brookes)

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This rare shadow transit is visible during a few brief windows every 15 years, when Saturn's rings are aligned edge-on with Earth. During this time, the orbital plane of Saturn's largest moon, Titan, is well aligned to cast its mighty shadow over the gas giant's cloud tops.

Each Titan shadow transit is separated by a period of 16 days, equal to the amount of time that it takes for the moon to complete a full lap of its parent planet. The next transit begins at 1:52 a.m. ET (0552 GMT) on Aug. 19. From there, the moon's shadow takes a little over four hours to sweep across Saturn's disk, according Sky & Telescope.

Saturn can be found shining around 40 degrees above the southeastern horizon as the transit kicks off on Aug. 19. For reference, the width of your clenched fist held at arms length accounts for roughly 10 degrees in the night sky.

Efrain Morales captured this view of a Titan shadow transit on July 18 earlier this year. (Image credit: Efrain Morales)

At that time, the gas giant will be approximately 807 million miles(1.3 billion kilometers) from Earth, rendering the event invisible to both the naked eye and binoculars alike. However, an 8-inch telescope at 200x magnification should provide a clear view of Titan's shadow on Saturn's surface, according to Hayden Planetarium instructor and lecturer Joe Rao. It may also be possible to track the transit using a smaller 4-inch scope, though this would be challenging even under excellent atmospheric conditions.

Upcoming Titan Shadow Transits (timings from Sky & Telescope in ET)

Date	Start	End
Aug 3	2:25 a.m.	7:04 a.m.
Aug 19	1:52 a.m.	6:00 a.m.
Sept 4	1:25 a.m.	4:50 a.m.
Sept 20	1:09 a.m.	3:34 a.m.
Oct 6	1:32 a.m.

Once Titan's shadow exits Saturn's disk after Oct. 6, the next opportunity won't come until this alignment recurs, likely in the mid-2040s.

Editor's Note: If you capture an image of Titan's shadow on Saturn and want to share it with Space.com's readers, then please send your photo(s), name, comments and the time/location of the shoot to spacephotos@space.com.