- by John Hlynialuk
There is one object over all others, which when seen for the first time in a telescope evokes a mixture of amazement and incredulity. No matter how many pictures of Saturn you have seen in textbooks, seeing it with your own eyes is always awe-inspiring. Once in a while, I even get profanity! OK,"Holy cow!" is not really that profane, but the comments are always expressions of delight and I always enjoy them.
You should never miss a chance to look at Saturn when it is in the sky and this summer, it will be easy to find, -look to the left of the Milky Way above the southern horizon. You will quickly become familiar with the constellation below Saturn, Sagittarius, which looks more like a teapot than an archer. See my star chart which shows the teapot stick figure. There will be an extra "star" above the triangular lid, -watch carefully and you will notice it moving (a planet's tell-tale signature) a short distance westward against the background stars over the summer.
Even an inexpensive telescope will show the rings fairly clearly but a better quality refractor, with a 2 or 3-inch lens, or a reflector of 5 or 6-inches aperture will show the Cassini Gap, a division in the rings. You can also see Saturn's moons, -on occasion, I have spotted five, but they are not as bright as the moons of Jupiter. (I had one student who said he could see some of Jupiter's moons with his naked eye, -I tested him on it and he was right. He had remarkable eyesight!). Not so for Saturn which looks just like a bright star. Through a telescope on nights of good seeing, it is possible to pick out two rings, the "A" and "B" ring. On exceptional nights, a faint third ring (the "C" ring or "Crepe" ring) closer to the planet's disk can also be seen. Spacecraft have discovered dozens of additional faint rings often with small moons imbedded in them. Rings have also been found around Jupiter, Neptune and Uranus but none are visible in even the largest amateur telescopes. (Rings around Uranus, you say? Please... no more Uranus jokes!)
Galileo saw the rings first in 1610, but in his crude optics, he saw three stationary "stars" or some strange appendages ("ears?") attached to Saturn. With a much better telescope in 1616 his drawings showed the planet and rings like we see them now, but he was still puzzled by them. To add to the mystery, he watched the "ears" disappear and reappear a year later (as he predicted they would). This is because twice during a complete Saturn orbit of 29.6 years, our line of sight passes through the plane of the rings which are thin enough to disappear. It is like trying to see the thickness of a sheet of paper at a distance of several kilometres.
Back in Galileo's day, to preserve the priority of a discovery, one announced it in an anagram, which was decoded by the discoverer upon confirmation. Galileo announced his discovery as "smaismrmilmepoetaleumibunenugttauiras" which later he revealed to be a Latin phrase that translated into "I have observed the most distant planet to have a
triple form". Fifty years later, in a much better telescope, Christiaan Huygens saw them as rings not touching the planet anywhere and provided this anagram
" aaaaaaacccccdeeeeeghiiiiiiillllmmnnnnnnnnnooooppqrrstttttuuuuu". Upon confirmation three years later, Huygens decoded his anagram into: "It [Saturn] is surrounded by a thin, flat, ring, nowhere touching, inclined to the ecliptic". The original anagram could also have been Huygens' sigh of relief when he finally got the credit he deserved!
We now know that planetary rings are the remnants of small moons that wandered too close to a parent planet's immense gravity. The moons break apart and spread out into flat disks of small rocks, bits of ice, and snowflake-sized particles, literally like millions of tiny moons.
More recently, the Cassini spacecraft circling Saturn determined that the rings are much younger than previously thought. They are probably only a few hundred million years old and may not be around much longer, becoming like the very tenuous, invisible rings around the other gas giants in the outer solar system, and basically disappearing from our telescopes.
So do not miss your chance to have a look at Saturn this summer. Its rings are as wide open as they can get in 2018. Join BAS for viewing nights in various locations in Bruce and Grey over the next few months. See www.bluewaterastronomy.com for the schedule. You just have to see Saturn's rings with your own eyes.
