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An Observing Guide to Saturn

The planet has more to see than just its rings.

by Alan M. MacRobert

Saturn
Damian Peach acquired this image of Saturn on December 24, 2002, from Tenerife, Canary Islands, using an 11-inch Schmidt-Cassegrain telescope and a SBIG ST-5c CCD camera. Colors and contrasts on the globe have been enhanced. South is up.
Ask amateur telescope users what's the most beautiful thing in the sky, and lots of them will say Saturn. In fact many say their first sight of it was what turned them on to astronomy. A view of Saturn in a good telescope often draws gasps from visitors, who after a lifetime of seeing cartoon ringed planets are awed by viewing the original.

But you can never see Saturn as well as you want! The planet is tiny as telescopic targets go; it's barely 21 arcseconds in diameter at its most favorable oppositions. Saturn's ring system is 2.25 times as wide as the ball — but that's still smaller than the width of Jupiter near opposition. And the disk itself shows only about 1/6 the area of Jupiter. Try to magnify it too much and it defies you by turning into a blurry mess. Saturn is indeed a jewel, exquisite but tiny.

Saturn in a telescope
These images suggest how the ringed planet Saturn might will look when seen through a telescope with an aperture 4 inches (100 mm) in diameter (top) and through a larger instrument with an 8-inch aperture (bottom).
Sky & Telescope illustration; source: NASA/Hubble Space Telescope.
However, with time, patience, and a top-quality 4-inch or larger telescope, you can tease out more of the planet's secrets than many observers suspect. But don't expect Hubble-like performance from your backyard telescope. The image pair on the right suggest how the ringed planet might look through a small telescope on a mediocre night (top) and through a larger, better telescope on a night when the air is especially still (bottom).

In winter and spring 2006 (Northern Hemisphere seasons), Saturn hovers within the small, dim constellation of Cancer, the Crab, in good view during evening. (Saturn passed opposition on January 27th.)



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