To Arcturus and the Northern Crown!

Hey, Sky Fans! Scott here. Happy Monday. I hope everyone had a good weekend. It’s been a tough few days. I hope you’re getting by.

I’m late today, but the meetings are done, Al Green is on the hi-fi, and the coffee is fresh and hot. So, at long last…

Did you see the Moon and Jupiter on Saturday? The skies here were clear and beautiful. A couple of people in the neighborhood were out and feeling chatty. Alignments like those are always wonderful on their own. When you stop to think, and have a chance to talk with other people about what we’re really looking at it, two of our closest neighbors along the same line of sight, wow… I always get a great sense of place from it.

As I turned to come inside, I looked around for a few other stars, and snapped this shot of the southeast’s sky with my little pocket click-o-cam set for 15 seconds at ISO400. Someone was kind enough to label the sky right when I had the shutter open. Here’s a non-emboxified version.

Corona Borealis near Acturus, June 3, 2017
Corona Borealis near Acturus, June 3, 2017

Sort of in the middle, you can see one of my favorite stars: orange Arcturus, the brightest star in the constellation Boötes, the herdsman. It’s fourth brightest in the entire night sky, and the second brightest visible here in the northern half of the Earth. Do you know the other three?

Once you’ve followed the arc of the Big Dipper’s handle to Arcturus, you’re in a part of the sky that doesn’t have a lot going on, so Arcturus really stands out.

You want astroexcitement? I’ll give you astroexcitement. The root of Arcturus’s name, arc, comes from Greek, and means “guardian of the bear.” It refers to Ursa Major, the great bear, which is in the northern sky. In turn, arc is the root of the word Arctic, itself an allusion to Ursa Major. Right, so, Arcturus guards Ursa Major, and by extension, the entire north, from all the frightening miscellany a giant astronomical bear can’t protect itself from.

It’s an old star; a red giant, about 36 light years (LY) away. If you’re at that part of your life, you’re looking at light that left it right around when you were born. Meanwhile, the good people living there are only now getting their first glimpses of Indiana Jones in Raiders of the Lost Ark, mere minutes after they saw Han Solo frozen in carbonite.

If you can, try to imagine that distance. Think of all of the things you’ve been through in that time, while those photons have silently and patiently made their way through space for their one shot, their one chance, at your eye. And 36 LY years isn’t even very far as these things go!

Red giants like Arcturus are similar to the type of star our own Sun will turn into billions of years from now, as it cooks through its hydrogen fuel. It’s a bit of a stretch, but, in some way, looking at it is like looking at our own future.

In the box, you can see a friendly, almost-complete circle of stars. That’s another small and easy constellation, Corona Borealis, the northern crown. We’ve talked a bunch about some of the great, smaller constellations, and here’s another for your collection.

Corona, which is even smaller than Corvus, is about 20 degrees — the width of both of your fists held out at arm’s length — to the left of Arcturus, at the moment. The rest of the crown curves out behind the moderately bright double star, Alphecca, in both directions. Keep an eye on that group of stars as the summer goes on. You’ll see it slowly rise higher and higher through the night. Watch it rotate and move above Arcturus, following it to the horizon. By late July, it’ll be shining high in the southwest by mid-evening.

Scorpius, certainly stunning, always gets the summertime press. For my dime, the smaller and dimmer Corona Borealis, is at least as great a place to spend summer nights. I hope you’ll try it on (get it… crown… you can wear… sigh…)

Clear skies, everyone!



11 thoughts on “To Arcturus and the Northern Crown!

  1. I could easily make out the crown in your biggified version. I agree, it is always fun when others are out and ask some questions about what you are doing. A few years ago I had some fun when Venus was high in the afternoon sky following the Sun. I took my Astroscan to the pedestrian area downtown, got it in the view, then asked people if they would like to see Venus. Some were convinced it was the crescent Moon. Others were amazed. Some shied away from me like I was dangerous.

    Liked by 2 people

    1. Hah… yeah, I know the feeling… one of the nights when we were having all of those total lunar eclipses a couple of years ago, I got to talking to a bunch of neighbors, a small class, I guess, about how it all works. It was a great few minutes, but it was funny/amazing how many of people quickly turned away, as if we were all part of some plot.

      Liked by 1 person

  2. You must have way better skies than mine. I doubt I could get the crown with 15-seconds and ISO 400. Maybe I will have to try…

    By coincidence I was specifically observing the area of the Northern Crown this weekend. I used it to find Hercules and the cluster by the same name, first time this year.

    Awesome explanation on Arcturus.

    Liked by 1 person

    1. Wow… Hercules. That’s one I never have any luck with. Thanks for the nudge. I’ll have to give it another shot some time.

      My skies are okay, I guess… I live on a darker-than-average street in a darker-than-average suburb, but it’s an overlit suburb near a giant city nonetheless. Truth be told, I’m amazed at what I can see there sometimes, and shocked at what I can’t.

      Thanks… I’m glad you liked it. An awesome star deserves an awesome description.

      Liked by 1 person

      1. I am about 25 miles west of Chicago. If you look at any light pollution map of the US, the city and its surrounding areas are an obscene blight, worse that just about anything along the east coast.

        Still, fortunately (for now) I don’t have too many intrusive lights. I have trained myself to see Ursa Minor and Draco. I did make out Hercules the other night. I can easily see the Orion Nebula.

        But my limit is that Orion is the only deep sky object I can see unaided. I cannot see the Andromeda Galaxy at all, and even through my 10″ reflector it is just a slightly un-dim smudge of the galactic center. It could be worse but I’d like it to be far better.

        Liked by 1 person

      2. Yeah… same here, more or less, I guess. I live in a pocket of relative darkness surrounded by unfortunate and unnecessary brightness. I can see nebulosity in the Orion Nebula, and on the clearest, stillest, midnightest of summer nights, I can see the faintest shading where the Milky Way is, high overhead; one of those “if you know it’s there, it’s there” kind of things. No sign of M31 whatsover, but I can pull out the thumb print smudge in my 15×70 binoculars.

        Liked by 1 person

      3. Interesting. You at least have some glimmer of the Milky Way. I have yet to see it in my neighborhood.

        Out of curiosity, how heavy are those 15×70 binoculars? Do they need a tripod?


      4. Yeah… I love the binoculars (Celestron Sky Master 15×70). They’re heavy but manageable. I’m not a muscular guy (what? really?!), but I’m able to hold them steady enough for a couple of seconds. I’ve been going with them a couple years just bracing my belt elbows on mailboxes and car roofs and stuff, you get it. A tripod would certainly be a good idea. I have a post in the works about a telescope I got recently, where I’ll talk more about this, but… long story short… I have a tripod now.

        They come with an attachable screw-in mount, though, which is a huge, huge bonus.

        Liked by 1 person

    1. Heh… thanks! I remember being a little confused when I saw Raiders of the Lost Ark and The Empire Strikes Back on the same day. Why wouldn’t people living around Arcturus? 🙂


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