On January 1, 1610, featuring a cool crisp night without cloud, Galileo saw the rings of Saturn through his telescope. Galileo had made this telescope himself and had only been using it for a few months. As he focused on this object in the black of space, he figured he had found a triple planet comprised of two smaller planets on each side of a large one.
Galileo had set some eyeglass lenses into a tube and manufactured a refracting telescope. The primary lens closest to the object he viewed was convex to collect as much light as possible. This produced a bright but blurry image. Further down the tube, he set a secondary lens that was convex and concentrated or sharpened the light to produce a focal point at which Galileo’s eye could see the celestial object as clearly as the magnification of these lenses allowed.
Working with this instrument with an approximate magnifying power of 20 times normal vision, Galileo wrote descriptions and drawings of the incredible things he could see. Today’s amateur astronomers might consider the power of Galileo’s telescope to be in the low range of general night sky viewing.
But here’s the thing. On this day, only a few people on the planet were starting to look at the night sky with a telescope. Certainly no one as well educated and curious as Galileo. Exciting is hardly the word to describe what was suddenly clear and thrilling, up Big and Incredible in the night. Just to see the moon close-up, filling the eyepiece with only a quarter of its image, enough to see it had mountains and craters… for the very first time… EVER. Think about it.
A few months later, he would publish The Starry Messenger that created a bestselling sensation in the science world and kicked the science of telescopy into gear.
As for Saturn’s rings, Galileo continued to refine his optics and a few years later he figured it was a planet with parts of two moons showing on each side. He was not able to know he was viewing elliptical space between the rings of Saturn… or that his view of Saturn and his angle of viewing the rings would change from year to year. Or, that over 400 years later, scientists would still be investigating to thoroughly understand Saturn’s rings.
B Bondar / Real World Content Advantage