The Hairiest Constellation

I’m back. All went well. Once the aliens were able to replicate and taste their first Chicago hotdog, their gratitude was boundless. My cohorts and I were released, and at least for now, Earth is safe.

We’re elated to be back. Turned out they had a fondness for Rebecca Black’s “Friday” song and played it incessantly through the ship’s sound system. I can’t tell you how happy I  am it’s Saturday.

To navigate to Coma Berenices, shoot a line through the top of the Big Dipper Bowl to Regulus, Leo's brightest star, found at the bottom of the 'Backwards Question Mark' figure that forms the lion's head. Look about two fists below to find his triangular tail. Coma Berenices lies between brilliant Arcturus and the tail. This map shows the sky facing east around 9 p.m. Maps created with Stellarium

New Moon is tomorrow, which means we’ve got about a week of dark, moonless evening skies ahead. That’s just what we’ll need to see a really cool constellation that practically hides in the shadow of Leo the Lion. It’s called Coma Berenices (Bear-en-EYE-sees) and refers to the hair (coma) of Queen Berenice II, a real queen who lived in Egypt in the 3rd century.

The constellation outline is little more than a right triangle composed of three dim stars. Instead, the real treasure here is what the ancient astronomer and mathematician Ptolemy referred to as ‘a nebulous mass’. If you look directly behind Leo’s tail star Denebola (den-EB-oh-la) from a moderately dark sky, you’ll be struck by a bunch of tiny stars, a.k.a Berenice’s curly locks.

Coma Berenices and the 'hairy' stars are one outstretched fist to the left and above Leo's tail star Denebola. If you have difficulty seeing the star cluster, try low power binoculars.

I’ve never counted them, but a glance will show at least a dozen and maybe a few more. If you sweep eye around the cluster in a technique called averted vision instead of staring directly at them, you’re sure to come across it.

Berenice's Hair (lower right) is below Canes Venatici the Hunting Dogs and right or west of the human figure, Bootes the Bear Guardian. Credit: Urania's Mirror

This swarm is a true star cluster and one of the biggest visible to the naked eye, measuring some five degrees or ‘half a fist’ across. One reason for its size is how close it is to Earth – a mere 288 light years. Only the Hyades in Taurus and a very spread-out cluster centered on the stars of the Big Dipper are closer.

Like other star clusters, Coma’s ‘hairy mass’ is a gravitationally bound system. All its stars are near one another and hang together as a unit in space as they orbit the center of the Milky Way galaxy. Astronomers know Berenice’s Hair as the Coma Star Cluster or Melotte 111, after the early 20th century astronomer Philibert Melotte, who compiled a catalog of open clusters.

A photo of Coma Berenices and Mel 111 shows how large and naked-eye rich the cluster is. Photo: Bob King

What’s a bit odd about Mel 111 is its location. Most star clusters of its type are found in the spiral arms of the galaxy. That means you’d expect to see it against the background of the misty Milky Way that cuts across the sky on early April evenings from northwest to southeast. The Coma Star Cluster is off by itself near the galaxy’s north pole. Why is still a bit of a mystery.

Take a look the next clear night. If you already know where Leo is, you’re in great shape to find Coma. Still in the dark on Leo’s location? You can use the Big Dipper, which now stands high in the northeast at nightfall, to navigate to Leo and from there to the queen’s hairdo.

8 Responses

  1. thomas s

    hi bob, yes i have observed coma, a long time ago in the days when my eyesight was sharp (then i could even distinguish the horse and rider in the handle of the dipper) and before i moved to an urban area where stars were dimmed by city lights. didn’t have a decent telescope in those days, couldn’t afford one so never got a chance for a good look at mell 111. keep it coming.

  2. stormchaser

    If I had to hear “Friday” playing like that, I’d aim for the emergency hatch and jump to my demise. lol

  3. VXIII

    I also live where the city lights block out all the stars, the night sky here has a dull reddish cast to it and you cant see anything except for one very bright star to my west that looks like an asterix, Is that the ancient star referred to by the Babylonians as Ishtar? If I am not mistaken isnt she going to go under the horizon for a few months or so then appear again in the west and begin her journey across the sky again.

    1. astrobob

      Ishtar is a Babylonian goddess but I’ve never seen it associated with Arcturus — that’s the bright star you’re seeing in the western sky.

      1. VXIII

        I’m sorry AstroBob, should have asked that question a different way, according to a theory I have read, all myths and many ancient religions are said to be based on how man tracked stars through the skies and as they used to sit around campfires and looking at the stars they made the constellations and told colorful stories about their movement through the skies in a manner even children could understand, (for example, when they dissappear below the horizon, the constellation/character is said to have “died” then when it comes back right on time as alway, it is said to have risen again) and these myths began to include Gods and Goddesses.

        Knowing what you know about the stars would you see this as likely or unlikely? Thats why I was asking about Arcturus, Im trying to see if this fits in with the Babylonian Ishtar, so Im asking, does Arcturus go below the horizon and if so when and then when does it appear again and where? Sorry for so many questions, this will be my last one for a while…

        1. astrobob

          I don’t know enough about Babylonian mythology to say. Perhaps another reader could help in this. I do know that Arcturus eventually disappears in the northwest in November, which is also about the same time it becomes visible in a dark sky before dawn. Visibility depends on your latitude to some degree. If you live in mid-northern latitudes, that’s true, but if you’re in the southern U.S. it disappears a little sooner and take a bit longer to reappear in the morning sky. Right now for Duluth, Minn., Arcturus is visible low in the northwest during early evening twilight and in the northeast during morning twilight.

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