Science

Two heavenly crowns for late summer.

As you study the night sky and constellations, you soon begin to realize that some star patterns come in pairs.

In several cases, the brightest constellation is recognized as “major,” while the smallest or dimmest constellation is designated as “minor.” We see this with two bears (Ursa) and two dogs (Canis). The star pattern known as Leo (the Lion) is so prominent that there is no need to use the “major” designation, however there is a much smaller and fainter constellation nearby that goes by the name Leo Minor.

Then there are the star patterns that describe similar animals but without the “major” and “minor” designations. There are two water snakes (Hydra and Hydrus) and two horses (Pegasus and Equuleus). The creature that gives the former constellation its name possesses the unusual ability to fly, while the latter is simply a foal.

Related: Western Zodiac Constellations

Finally, there are similar constellations that are located in the northern and southern halves of the sky. In such cases, “borealis” refers to the northern group of stars, while “australis” refers to the south. There are two triangles and a southern fish. (The zodiacal constellation Pisces represents two fish, but without any reference to their positions north of the celestial equator.)

And let’s not forget the crowns.

The Northern Crown

There are two star patterns that represent crowns that are visible in our current late-summer night sky: Corona Borealis (the Northern Crown) and Corona Australis (the Southern Crown).

Corona Borealis is a small but elegant star pattern, just east of Boötes (the shepherd). In heaven, it actually looks more like a tiara. For many years, I always enjoyed pointing out the Northern Crown to the public at the Hayden Planetarium in New York during the month of September, commenting that it closely resembled the crown presented to the winner of the annual Miss America pageant. But since the pageant moved to December, I have to be a little more creative.

Today, I link Corona Borealis with Boötes noting that this latter star pattern looks like an ice cream cone. Start at the Big Dipper, then work your way along the curve of its handle until you reach Arcturus, which marks the bottom of the cone.

As I have told my audience, the cone does not contain ice cream but orange sorbet. We know this because someone bit into the bottom of the cone, allowing some of this delicious concoction to drip off, and that’s when I point to the pumpkin-colored Arcturus.

I go on to point out that there were originally two tablespoons in this cone. We can see the lower blade embedded in the cone, but the upper blade has fallen off. That second inverted blade, placed just to the left of the top of the cone, is Corona Borealis; An alternative interpretation of the Northern Crown!

Whether you envision it as a sherbet ball or a crown, here are a couple of other interesting facts about this beautiful circle of stars.

The brightest star in Corona Borealis is Alphecca of the second magnitude, better known as Gemma, the jewel in the crown, perfectly placed in the middle of the arch. For positive identification, an imaginary line of Megrez, the star that connects the bowl to the handle of the Big Dipper, stretched to Alkaid, the star at the end of the handle, and then extended twice the distance between these two stars, you will take directly to the crown.

Sadly, this is only a momentary formation, as the stars are tumbling in different directions. For example, Gemma and Nusakan, a star immediately adjacent to it, have opposite movements and in the last 75,000 years they have almost switched places.

Another rather surprising feature of the Northern Crown is that within its limits is a very rich cluster of distant galaxies, known as a supergalaxy. It is one of the most remarkable of all these aggregations, made up of more than 400 galaxies. However, the cluster is extremely remote; estimates put it 1.3 billion light-years away and it is moving away from us at 13,000 miles per second (21,000 kilometers per second), or about 1/14 the speed of light.

The Crown of the South

Corona Australis, the Crown of the South, is located above the southern horizon at dusk this week, below the famous Sagittarius Teapot asterism.

Unfortunately, this corona is set so low in the sky when viewed from northern mid-latitudes. Most of the time, this conspicuous narrow semicircle of stars is hidden from view by a low haze near the horizon (its brightest stars are only fourth magnitude). When viewed from New York, it barely rises 10 degrees above the horizon. As we mentioned before, 10 degrees is about the width of your fist held at arm’s length, so the southern crown never reaches much higher than “a fist” above the southern horizon. You have to go to the southern US or the tropics to get a good view.

And in the same way that I used Boötes with Corona Borealis, about half a century ago, the late popularizer of astronomy George Lovi (1939-1993) pointed out that we could augment the Teapot with a teaspoon and a lemon wedge. Lovi’s teaspoon contains stars in Northern Sagittarius, while her lemon wedge is an alternate version of Corona Australis.

The obsolete crown (third)

At this point, I think it’s fair to mention a third crown that once adorned some, but not all, star atlases in the late 18th century. It was conceived by the German astronomer Johann Bode in 1787 as his way of honoring Frederick the Great, the late King of Prussia who had died the previous year.

The constellation Bode created was made up of a jumble of faint stars that were taken from adjacent constellations of Andromeda, Lacerta, Cepheus, Pegasus, and Cassiopeia. Known as Gloria Frederica or Frederici (Frederick’s Glory), it was an arcane, shapeless star pattern that Bode described as a crown floating on a sword, feather, and olive branch, based on his perception of Frederick as a “hero, wise and peacemaker. ”

But in the late 19th century, Gloria Frederica was all but forgotten, and in 1930, when the official boundaries of the constellations were established, Frederici never made the cut.

Too! Had it survived, we could have had a version of the triple crown in the night sky.

Crown mythology

Both Corona Borealis and Australis are ancient constellations, part of Claudius Ptolemy’s list of 48 groupings (c. 87 to 150 AD).

Corona Borealis represents the gem-studded gold crown of Ariadne, a Cretan princess associated with labyrinths, who in Greek legend received the crown of Dionysus, the god of wine and fertility, upon marrying him.

However, the much more subdued Corona Australis represented a crown of leaves that was sometimes worn by the ancients on ceremonial occasions. It does not have a particular story associated with it, although some write that it was another crown that Dionysus gave him as a gift, this one to his mother Semele.

Think about it for a moment: Dionysus gave his future wife a magnificent jeweled gold crown, while he gave his mother a mere crown of leaves!

Joe Rao serves as an instructor and guest speaker at the Hayden Planetarium in New York. He writes about astronomy for Natural History magazine, Farmers’ Almanac, and other publications. Follow us on Twitter @Spacedotcom and on Facebook.

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