Sunday, July 13, 2014

Saturn



Order from Sun: 6
Named For: Roman god of agriculture
Diameter: 72,370 miles
Volume: 763x Earth
Gravity: 1.07x Earth
Distance from Sun: 886 million miles
Orbital Period: 29.44 years
Orbital Inclination: 2.49 degrees
Orbital Eccentricity: .053
Length of Day: 10.65 hours
Temperature: -288F
Composition: Gasses
Atmospheric Composition: hydrogen, helium
Moons: 150+
Rings: yes, prominent
Notable Exploration: Pioneer 11 (1979), Voyager 1 and 2 (1980, 81), Cassini-Huygens (2004-present)


The last planet known to the ancients and the second largest planet, Saturn appears to the naked eye as a star shining around magnitude -.5. Saturn takes about 30 years to orbit the Sun and thus spends just over two years in any given constellation of the zodiac. Like Jupiter, Saturn shines at a relatively constant brightness thanks to its immense distance from Earth.

In high-powered binoculars on a tripod, Saturn's famous rings, while not being truly resolved, do present themselves in that the planet seems to have an oval shape to it, which Galileo termed as “ears.”

Like Jupiter, even the smallest telescopes transform Saturn from a featureless disc into a wonderful world that must be seen to be believed. First of all, there are the famous rings, which appear easily at around 50x power. With larger scopes and higher powers, one can see gaps in the rings, most famously the Cassini Division, named after its discoverer, 17-18th century astronomer Giovanni Cassini. With very large scopes under steady skies, smaller divisions may also appear on a good night. Another thing to look for with Saturn are color bands, which are far more subtle than on Jupiter. With Saturn's rings, there is an interesting phenomenon that takes years to present itself. Because of the angles of Earth and Saturn relative to each other, Saturn's rings appear to 'open' and 'close,' with, once every # years, the rings becoming edge-on and disappearing from view altogether. This slow progression can be observed in even the smallest of telescopes. Back to the big scopes, look for Saturn's moons. While giant Titan is easy to see, it can be possible to spot some of the other, much smaller ones, too.

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