Sky Showpiece: See Saturn and Titan

Sky Showpiece: See Saturn and Titan
SKY MAP: Saturn at 7 p.m. on Jan. 28 from mid-northern latitudes. (Image credit: NULL)

With the bright Moon having departed the evening sky, this is the week to enjoy Saturn. Now located among the stars of Gemini, the ringed planet is readily visible as a yellowish-white "star" in the winter night sky.

A small telescope will also reveal Titan, the moon that's now in the news after a successful mission to land on its strange surface.

Now two weeks past opposition, it is readily visible low in the East-northeast as darkness falls and is visible for virtually the entire night. It currently shines at magnitude minus 0.3. On this astronomers' scale, smaller numbers represent brighter objects, and negative numbers are reserved for the brightest of all.

In mythology, Saturn closely resembled the Greek god Cronus, but he's more usually recognized as the Roman god of agriculture. The name is related to both the noun satus (seed corn) and the verb serere (to sow). But why would the planet Saturn be linked to agriculture? Perhaps a clue can be found from the ancient Assyrians who referred to Saturn as lubadsagush, which translated, meant "oldest of the old sheep." Possibly this name was applied because Saturn seems to move so very slowly among the stars; it may have also reminded skywatchers of the slow gait of plowing oxen or cattle.

The ancients also regarded Saturn as the "highest" planet, occupying the outermost or highest sphere before that of the fixed stars.

The first glimpse of Saturn's famous rings were made by Galileo Galilei (1564-1642) who pointed his crude, imperfect "optick tube" toward Saturn, and saw it appearing to have an odd pair of appendages or companion bodies on either side. He announced this discovery in 1610 with an anagram written in Latin.

The jumbled letters could be transposed to read: Altissimum planetam tergeminum observavi ("I have observed the highest planet to be triple."). But later, when the rings turned edgewise to Earth and the two companions disappeared, Galileo invoked an ancient myth when he wrote, "Has Saturn swallowed his children?"

Prior to 2003, the last such occasion in September 1988; the next will be in October 2017. Still broadly displayed to our view now, the rings are gradually tipping away from Earth and by August 2009 they'll be turned edgewise to us and become difficult, if not impossible to see.

After seven years of travel through the Solar System, the Cassini spacecraft reached Saturn last July to begin a 4-year voyage of discovery of the mysteries of the Saturn system. A highlight of the Cassini mission, led by NASA, was the deployment and landing of a small spacecraft built by the European Space Agency - the Huygens Probe - on the surface of Saturn's largest moon, Titan on Jan. 14.

Other satellites that might be viewed, depending on the size of your telescope, are Rhea, Tethys, Dione and Iapetus. Saturn's other satellites, are much smaller (the smallest, 2003 SI, has an assumed diameter of just 3 miles, or 5 kilometers) and are only visible with very large instruments. Other than Jupiter, Saturn is the planet that has the most moons - at least 31 at last count.

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Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.

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Joe Rao
Skywatching Columnist

Joe Rao is Space.com's skywatching columnist, as well as a veteran meteorologist and eclipse chaser who also serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky & Telescope and other publications. Joe is an 8-time Emmy-nominated meteorologist who served the Putnam Valley region of New York for over 21 years. You can find him on Twitter and YouTube tracking lunar and solar eclipses, meteor showers and more. To find out Joe's latest project, visit him on Twitter.