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Saturn Opposition 2017 June 16, 2017

Posted by aquillam in Astronomy, MichiganAstro, Urban Observing.
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It’s summertime, and that means Saturn-time!

But why is that?

A year on Saturn is a bit more than 29 years on Earth, which means Saturn moves about 12º along the ecliptic each year. For comparison, the Moon moves about 15º per day, so in a whole year, Saturn’s position will change less than the the Moon changes in a single day! It fact it’s so little that it take Saturn an average of two years to move through each zodiac constellation. Last year Saturn crossed the boundary into Ophiuchus (between Scorpio and Sagittarius), and it won’t leave until December. That means Saturn will be visible in the evening at about the same time this year as it was last year.

Ophiuchus is often called the 13th zodiac because itt sits between Scorpio and Sagittarius

Saturn takes 29 years to make a complete circuit of the ecliptic

Of course 12º isn’t nothing. Each year opposition drifts just a little farther east along the ecliptic, so the date changes. And since there are 360º in a circle and 365 days in a year, the date corresponds to roughly a degree per day! This year, opposition was June 15th. In 2016, it was June 3, and in 2015, May 23. Next year, opposition will be June 27.

By the way, opposition is when something (like Saturn) is opposite something else (like the Sun) in the sky. So when Saturn is at opposition, it rises at sunset, then sets at sunrise. Each night it rises a little earlier, so the weeks following opposition are the best time for evening observers to get a look. Closest approach is always close to opposition too, so the planet will be bigger and brighter than usual.

elpOrbitsOpp

At opposition, the Sun, Earth, and outer planet are on a line with the Earth in between.

elpOrbitsClose

Because the orbits aren’t circles, the Earth may get closer to the outer planet a few days before or after opposition.

 

So enjoy summertime Saturn while you can. In about 4 more years, it’ll be fall when Saturn’s out.

Venus brightest around February 16 | EarthSky.org February 16, 2017

Posted by aquillam in Astronomy, MichiganAstro, Urban Observing.
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If it’s clear where you are this evening (or the next several evenings really), look high in the west about half an hour after sunset. That incredibly bright point of light you see is not a star, it’s Venus! If you happen to have a small telescope or good pair of binoculars, take a look at it. You’ll see it’s actually a crescent!

As long as you’ve got your telescope/binoculars out, be sure to check out the little red point nearby. That’s Mars. In fact, it’s pretty much a full Mars. How can two planets be so close in the sky and so different in appearance? Because one of them is nearby, almost between us and the Sun, while the other is far away, with the Sun in between.

For more on Venus, check out this story from Earth-Sky:

 

Venus is brighter around February 16-17, 2017 than at any other time during its ongoing, approximate, 9.6-month reign in the evening sky.

Source: Venus brightest around February 16 | EarthSky.org

Urban Observing June 2016 – Planets version June 7, 2016

Posted by aquillam in Astronomy, MichiganAstro, Urban Observing.
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I’m a little overloaded these days, but there’s so much good stuff in planets I wanted to get those out there.

Mars Opposition was on May 22, and it’s closest approach on May 30, so early June is still a great time to check out the red planet.

It’s not far from Saturn, which is at opposition on June 3. It has a nice tilt now too, so it’s a great month for cell phone pictures through a telescope.

Jupiter is still a great evening target. Look for it high in the south at sunset. It’s only 1º from a first quarter moon on the 11th.

11June2300SE-W.png

Morning observers get some of the easiest viewing of Mercury the first 2 weeks of the month. Of course, the early sunrise means you’ll have about a 15 minute window 30 – 45 minutes before sunrise to catch it. Greatest western elongation is on the 5th, but the best angle relative to the horizon is the 13th (at least at 42º latitude.) Binoculars will help.

13June0520ENE.png

Venus fans are out of luck. Superior Conjunction is on the 6th, so it’s lost in the Sun’s glare most of the month. If you’re up for challenge, start watching for it in the evening at the end of the month.

The lowest full moon of the year will be on June 20. If you’re a fan of optical illusions, check it out – the low altitude enhances the Moon Illusion.

Mercury and the Moon binocular challenge June 2, 2016

Posted by aquillam in Astronomy, Urban Observing.
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Using binoculars, and a clear ENE horizon, you can spot a very old Moon and Mercury tomorrow morning. About 45 minutes to an hour before sunrise, go out and look for the bright Star Capella in the north east. Drop your view about 5° toward the horizon, and scan to the east. With a little luck, Mercury and a very old old moon will pop into view.

02June0530ENE.png