That big, bright object in sky is Jupiter
The king of the planets is jumping out at you in the early evening sky and stays out all night long. Not only that, it will be in our Butler evening sky through the coming summer.
Jupiter has reached its closest approach to Earth this month, something astronomers call opposition. Right now the great planet is a little over 415 million miles away.
Believe or not, that's close for Jupiter. The Earth and Jupiter reach opposition every 13½ months as both planets circle the sun in their own individual orbits. Because Earth's and Jupiter's orbits are not exactly circular, Jupiter is actually at its closest opposition since 2014.
It's by far the largest planet in our solar system, with an equatorial diameter of 88,000 miles, dwarfing our 8,000-mile wide Earth. In fact, if Jupiter were a hollow sphere you could fill it with well over a thousand Earths.
Without a doubt Jupiter is the brightest starlike object through the night and is a great telescope target, even for smaller scopes. As tempting as it is to view it through your scope as soon as darkness sets in, I strongly advise you to wait until after 10:30 or 11 p.m. when it's higher in the heavens. When Jupiter or any other celestial body is low in the sky you're forced to look through a lot more of our Earth's blurring atmosphere.
Jupiter is basically a huge ball of hydrogen and helium gas, much like our sun. The gas gets thicker and denser as you approach what's believed to be the planet's rocky core. So when that asteroid hit Jupiter in late July it never made landfall, because there is no real land.
When you get Jupiter in the eyepiece of your telescope you'll see at least some of the horizontal parallel cloud bands on the disk of the gargantuan planet. Even the smallest of scopes with decent focus can usually pick up two of the dark cloud bands, running on either side of Jupiter's equator.
But since Jupiter is so close this month you'll probably see a lot more. You may even see some light color in the bands. I can't believe how well I'm seeing Jupiter with my big scope these nights.
The clouds on Jupiter are mostly made up of ammonia and methane compounds. They swirl around Jupiter at speeds up to and over 200 mph and contain eddies and storms within them. The biggest of Jupiter's storms is the famous Red Spot that's way bigger than even our Earth. Other smaller red spots also have been seen on the great planet.
Jupiter's atmosphere is so active because of the planet's immense mass and resultant huge gravitational force. That gravity literally puts the squeeze on Jupiter and compresses the giant gas ball. That compression produces a lot of internal heat that drives the energetic Jovian atmosphere.
There also is a lot of lightning on Jupiter. In addition, because of the huge magnetic field generated by the rapid rotation of the planet, aurora are common around Jupiter's poles. There's a lot going on around the big guy of our solar system.
When you're viewing Jupiter, or anything else in your telescope, another piece of advice I can give that really helps is to start with a lower magnification eyepiece and work your way up to a higher magnification. You will reach a point of limiting higher magnification where the image will really get too muddy.
There's no sense in seeing a blurry Jupiter, so bump down to a lower magnification. Remember also that not all nights are the same for telescope viewing. Even if the skies are clear, high winds in the upper and lower atmosphere can diminish what you see and how much magnification you can obtain clearly. If Jupiter doesn't come in too clearly one night, try it again the next night.
One other thing … it's always a good idea to look through your telescope at Jupiter or any other object for a continuous extended time. Try to keep your eye plugged to the eyepiece for at least 10 minutes at a time. That will give you more time to get used to the different light level and will allow you to see more detail.
Another attraction around Jupiter are its four largest moons that look like little stars in a line on either side of the planet, depending on where they are in their individual orbits. Even the tiniest of scopes and binoculars can pick them up. I even know some people that can spot traces of them with the naked eye.
I'll have much more on Jupiter's Galilean moons over the next several weeks.
Make the stars your old friends
If you have any astronomical questions or want me to write about something you're seeing in the night sky, drop me a line at mikewlynch@comcast.net.
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul and is author of the book, “Stars: a Month by Month Tour of the Constellations” published by Adventure Publications and available at bookstores and at http://www.adventurepublications.net.
