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Jupiter and Venus Hug in the West

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Catch the Conjunction!

The planets Venus and Jupiter in conjunction around June 30, 2015.
The planets Venus and Jupiter in conjunction around June 30, 2015.

Take a moment from your busy day to step outside after sunset tonight and the next few nights and check out the close conjunction of Venus and Jupiter in the western sky.  They make quite a pretty sight in the gathering twilight. I heard someone describe them as “hugging in the sunset” and that’s a very poetic way to see them.

June 30 conjunction view.
June 30 conjunction view.

“Conjunction” is an astronomy term that means “two objects look fairly close together in the sky”.  The formal definition is “when two objects in the sky have the same right ascension or ecliptical longitude when observed from Earth.” These astronomical events can include specific bright stars, as well, so occasionally you might see one or more of the planets in conjunction with a star such as Spica (in Virgo) or Regulus (in Leo).

What’s Really Happening?

As planets orbit the Sun (and as the Moon orbits Earth), they appear against a backdrop of stars, and occasionally other planets are in the view, too.  Think of it like being on a merry-go-round and looking out at the scenery as it goes by. People standing near the carousel appear against a backdrop of other people or trees or parking lots or whatever is out there.  They may all look close together, but in reality, they’re not. This is because we live in a 3D universe where objects are distributed throughout space.  From your perspective, however, they seem to be close together.

So, how far apart are they?  Right now Venus is about  670,198, 462 kilometers (416,442,017 miles) from Jupiter. (That’s 4.48 times the distance from Earth to the Sun.) If one of the planets happened to be in conjunction with the star Regulus, they would be 77.6 light-years apart! So, conjunctions are something of an optical illusion, collapsing the reality of space between them.

Conjunctions can happen on other worlds, and someday when we’re all living on Mars, we’ll be able to see events like this one that include Earth in the view. Until then, however, let’s make the most of the view from our planet! The planets are visible right after sunset and will slowly move toward the western horizon over the next few hours. Take out your telescope or binoculars to get a more detailed look at Jupiter. Happy gazing and clear skies!

 

'Casts, amateur astronomy, astrocast.tv, astronomy, Orion, Orion Nebula, our night sky, star charts, stargazing

Stargazing in February

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It CAN Be Done!

The first month of the year is behind us now, leaving 11 more months of sky sights to check out. February for many northern hemisphere observers is still the winter season, so of course you have to dress warmly unless you live in relative sunny climes. For southern hemisphere viewers it’s late summer, so the dress code’s a little different. No matter what you wear, though, there ARE some great sky sights to check out.  I outline a few of them in my monthly video called Our Night Sky, produced for Astrocast.TV. You watch it here.

A chart view of Orion, showing Betelgeuse in the shoulder of the giant. The three belt stars run through the middle, and just below them is the Orion Nebula starbirth region. Courtesy Zwergelstern on Wikimedia Commons.

I always come back to Orion for my sky gazing this time of year. It’s just a gorgeous star pattern.  What I like most about Orion: it provides a lot of interesting stuff to look at. There’s Betelgeuse, for example. It’s a red supergiant star in his shoulder, and it’s likely to pop off as a supernova anytime (well, “anytime” is relative — it could be in the next million years).

Notice the three stars across Orion’s middle. Just beneath them lies a spectacular star birth region called the Orion Nebula. It’s about 1,500 light-years away from us and it just blazes with hot young stars, set among clouds of gas and dust that are still forming stars.

I’ve been stargazing since I was a kid. I didn’t always know what I was looking at, but over time (and using star charts and taking a few astronomy classes and teaching in the planetarium) I got to know the sky pretty well. You don’t have to do all that to explore the sky. You can start very simply: take it one constellation at a time.  Look at it with your naked eye, then scan it with binoculars or a small telescope.  Chances are, you’ll find something cool and interesting to check out each time you look.

People often ask me what star charts they should get. I always recommend they check out Sky&Telescope.com or Astronomy.com. Those two sites (and their associated magazines) have very useful star charts that you can customize for your location. If you have an iPhone or an iPad, you can get a wonderful app called Starmap. (Disclosure: I’m working on a project for these guys, but I was using their sky maps (free of charge on their site) long before they contacted me to work with them.)  I also very much like Skymaps, which provides both northern and southern hemisphere charts.  I also wrote about some good astronomy books and apps just before Christmas — check them out  here and here if you’re looking for some more extensive, tree-based information about where to look during your sky gazing sessions.  Now, get out there and check out the sky!  (Just be sure and dress for the weather!)