Jupiter Gets Big And Bright

Brilliant Jupiter and dimmer Saturn pair up in the southeastern sky in Capricornus, a faint constellation to the left (east) of the Sagittarius Teapot (outlined). Faint Pluto lies 1.8° to the lower left of Jupiter. The planet reached opposition this week. The “steam” rising from the “spout” is one of the brightest parts of the summer Milky Way. Bob King

Comet NEOWISE has dominated sky news, but I don’t like to miss a Jupiter opposition. About every 13 months Jupiter and the Earth line up on the same side of the sun and come closest together. Because the planet appears directly opposite the sun — rising in the east when the sun sets in the west — it’s said to be at opposition.

Jupiter and Earth are closest for the year this week, making the planet especially brilliant. Bob King

Today, 385 million miles (619 million km) separate the two planets. But next Jan. 29, when they’re on opposite sides of the sun, they’ll be 179 million miles (289 million km) farther apart. That’s a significant difference and the reason why Jupiter looks so incredibly bright right now. Closer also means the planet appears bigger when viewed through the telescope. And bigger is always better for seeing planetary detail.

Jupiter is currently the brightest planet in the evening sky, rising in the southeastern sky during evening twilight. It’s joined by Saturn, located just 7° to its left (east). They’re so close together you won’t be surprised to learn that Saturn comes to opposition less than a week later on Monday the 20th. That’s not all. Dwarf planet Pluto is at opposition today, July 15 — a trifecta! To see the 14th magnitude blip you’ll need at least a 10-inch telescope.

Jupiter and the Galilean moons as they’ll appear tonight (July 15) around 10:30 p.m. CDT through a small telescope. Stellarium

Through a pair of 7x or 10x binoculars Jupiter has a distinct shape and depending on when you look, up to four of its moons are visible. The planet has 79 confirmed satellites, but all but four are faint and small. Because Galileo was the first to see the quartet they’re known as the Galilean moons — Io, Europa, Ganymede and Callisto. Each orbits Jupiter with its own period, so every time you look at the planet in binoculars or a telescope (better) you’ll see a unique arrangement.

Telescopes show the moons not only off to either side of the planet but also when they pass in front of it during transits. You can sometimes see the moon itself hovering above Jupiter’s cloud tops during a transit, but the tar-black shadows (shadow transits) they cast are much easier to spot. Jupiter casts a shadow just like the Earth. When one of its moons passes into the shadow it temporarily disappears in eclipse. All this makes for wonderful, summer night entertainment for skywatchers. To find out which moon is which and for a list of upcoming eclipses and transits check out Sky & Telescope’s Jupiter’s Moons.

Jupiter shows off its two main cloud bands called the North and South Equatorial Belts on July 3. The white dot at the planet’s edge is the moon Europa during a transit. Damian Peach

Most small telescopes will show two dark, horizontal stripes across the planet called the North and South Equatorial Belts. Thinner temperate belts are visible north and south of the pair. Use low magnification to first find the planet and center it in the scope’s field of view, then increase the magnification to pick out more details. Jupiter has no solid surface. Everything you see are clouds made of ammonia ice crystals mixed with sulfur and phosphorus compounds that add extra color.

Through a telescope Jupiter displays prominent dark cloud bands alternating with bright “zones.” The colorful Great Red Spot is a vast, hurricane-like storm 1.3 times the size of the Earth that’s been around since the 1600s. Christoper Go

The most colorful feature on the planet is the Great Red Spot, an oval storm a little larger than our entire planet that’s been whirling around up there for more than three centuries. You’ll need a 6-inch telescope and magnification around 100x-150x for a clear view. From mid-northern latitudes Jupiter is rather low in the sky this season, meaning it’s more affected by atmospheric turbulence. Don’t be surprised if some nights it looks blurry through the scope. Back off the magnification and enjoy the moons instead. On nights when the air is steady and the planet super sharp, crank up the magnification and see how many cloud belts and other atmospheric details you can eke out.

Comet NEOWISE reveals a blue gas tail and a broad tail made of dust on July 14. Within the dust tail you can see individual rays synchronic bands likely created when individual chunks of the comets fragment. Bob King

All this is easy to do because you’re out looking at the comet anyway, right? When you’ve had your fill of that sky wonder, turn around and point those binoculars at the largest planet in the solar system. Did you know 1,300 Earths could fit in there?

7 Responses

    1. Hi Joe,
      You will start to see it low in the northwestern evening sky starting July 16. Conditions keep improving from there as the comet gains altitude.

  1. Alexander Natale

    Great post as usual Bob, Last night my wife and I found Comet Neowise (3rd time) and then just as you stated we turned the Edmund Astroscan telescope around and checked out Jupiter and Saturn. The icing on the cake was a beautiful Space Station flyby just as we were viewing the Comet. I might set up the Celestron Telescope tonight if the sky remains clear. Best Regards, Alex

    1. Great to hear, Alexander. Take a close look at the comet’s head or coma through the scope for interesting details you don’t see in binoculars.

  2. Edward M Boll

    The planets and stars were really bright tonight. Probably because of clear skies and no Moon. I was going to go out at 10:20 and see Neowise just coming into view. At morn it’s easy, set an alarm. When it goes off I know what it’s there for. But talking with my dad on the phone, I lost track of time. I thought oh no, the comet will be too low. Boy, it wasn’t as low as I thought at 11, and what a sight. Still fairly easy with the naked eye, because of a bright tail. Binoculars revealed a large like star head and the tail which made it seem like a space craft with exhausts coming out like it was getting ready to land. Driving back to my home, I thought the trees would wipe out my view of a low comet. But down our street was a clearing and I thought I still saw it right by my house. And indeed binoculars proved to me that if I wanted to see it, I merely need to step to the side of my house. I finally thought about why Hyakutake was brighter but the tail was only visible with binoculars. My conclusion when we saw that one in 96, it had not reached Perihelion yet.

  3. Edward M Boll

    Yes I did look at the 2 giant planets last night. Neowise fainter has my attention because I realize that within weeks we will lose sight of it without a telescope. Last night without the Moon it was breath taking, I would say mag 2.1.

Comments are closed.