Starwatch: Best sight in the night sky? It's got a ring to it

SW DIAGRAM B FOR JUNE 10-12, 2016.jpg

This late spring there's been a lot of stargazing talk about Mars, and for good reason. It's been as close to Earth as it's been since 2005 — 47 million miles away — and there's no way you miss it with that very distinctive reddish hue in the early low southeast sky. Without a doubt it's the brightest star-like object you can see in that part of the sky, and the second brightest star-like object in the entire sky right now. Only Jupiter, now in the southwestern evening sky, outshines Mars, but not by much.

There's actually a third planet easily available in the Rochester evening sky now that I'm afraid is being overlooked, literally. It's Saturn, the ringed wonder of our solar system. Saturn is also rising in the low southeast sky, not more than 18 degrees, or about two fist-widths, to the lower left of Mars. You'll have absolutely no problem spotting it since it's the next brightest object in that part of the sky.

I believe it's the most breathtaking planet you can view through a telescope, even a small one. When I'm conducting my astronomy and stargazing programs and Saturn's available to view, it's hands-down the favorite as folks see it through my arsenal of supersized telescopes. Viewing Saturn has been known to excite folks and really get them jump-started into amateur astronomy, especially young people.

Earth and Saturn are still at about their closest approach to each other for 2016. This is called opposition. That's when the Earth in its orbit around the sun finds itself in a line between Saturn and the sun. This happened last month with Mars, but in the case of the red planet it only occurs every 25 months.

With Saturn, we enjoy opposition about every 12-1/2 months, a little over one year. Saturn orbits the sun much more slowly than Earth, only once every 29 years. In the 365 days that it takes Earth to orbit the sun, Saturn progresses only about one-twenty-ninth of its orbit around the sun. Because of that, the Earth needs a little time to catch up to be in a line with Saturn, as you can see in the diagram. The ringed wonder of our solar system is still a ways off, at 837 million miles, but it's a heck of a lot closer than it was about six months ago when it was nearly a billion miles away. Another advantage of opposition is that Saturn is available all night for viewing, rising at sunrise and setting at sunset.


Farther, but bigger

Even though Saturn is more than 17 times farther away than Mars, Saturn is about 17 times the diameter of Mars, and that's not even counting the 185,000-mile-wide ring system diameter. I think it's much more fun to view than Mars. In the right conditions, you should be able to easily see the separation between the planet and the ring system, and you'll probably see at least some of Saturn's moons.

All of Saturn's 60-plus moons are pretty dim, with the exception of Titan, Saturn's largest moon. With a diameter of 3,200 miles, Titan is even a little larger than the planet Mercury, the closest planet to the Sun. Titan has a heavy methane atmosphere and even has methane lakes.

One of Saturn's tinier moons, Enceladus, is truly bizarre. Liquid water plumes gush from cracks in its surface. It's believed that tidal forces from the much more massive Saturn are strong enough to heat up Enceladus's interior enough for liquid water. Wherever there's liquid water, there's at least a small chance of some kind of life.

Low rider

At the start of evening darkness, Saturn is so low in the southeast sky that you'll probably be disappointed with what you see. By midnight, Saturn should be high enough to avoid at least some atmospheric blurring. What's a bummer this summer is that Saturn is not going to get all that high above the horizon, no more than 25 degrees above the southern horizon. Saturn may still be a little blurry even after midnight, but that's the celestial card dealt to us this year.

Saturn is basically a 75,000-mile-wide ball of gas, making it the second-largest planet in our solar system. Believe it or not, this planet's density is less than that of water, so if you could get a swimming pool big enough, Saturn would float on it like a colossal beach ball.

Saturn's hallmark, though, is the ring system. In fact, when you glance at Saturn with just the naked eye, most of the light you see from it is the sunlight reflecting off its rings. As wide as Saturn's ring system is, it's less than half a mile thick and in some places less than 30 feet thick. It's made up of billions and billions of ice-covered rocks that vary in size from pebbles to the size of an average house.


Celestial hugging

The nearly full moon will be hanging out with Saturn and Mars later this week. On Thursday night, the moon will be just above Mars. On Friday night the moon will be between and above Saturn and Mars. On Saturday night the moon will be just to the upper left of Saturn.

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