Passing Time With The Pleiades, The Late Night Skywatcher’s Fuzzy Friend

The Pleiades (middle right) and neighboring stars are reflected in Boulder Lake near Duluth, Minn. recently. Credit: Bob King

“Many a night I saw the Pleiads, rising thro’ the mellow shade,
Glitter like a swarm of fire-flies tangled in a silver braid.”

– from Locksley Hall by Lord Alfred Tennyson, Victorian poet

The Pleiades star cluster catches the eye of the late night skywatcher as we transition into September. Is there a surer sign of winter’s slow approach than the return of this little dipper of stars to the eastern sky? I saw the bunch last night struggling to clear the treetops around 11 p.m. By midnight it stood apart – a beautiful sight with both the naked eye and binoculars.
The bright stars in the Pleiades are named for the daughters of Atlas and Pleione in Greek mythology. Credit: John Lanoue
I love watching the Pleiades (PLEE-uh-deez). There’s nothing quite like it in the heavens. Most stars are single and separate from each other, but the Pleiades packs more than a handful into a single compact shape that stands apart from nearly everything else in the sky.
You’ve probably noticed that the cluster looks a little fuzzy. That’s due in part to seeing so many stars – some visible and many below the naked eye limit – so close together they blend and blur the same way billions of faint stars in the Milky Way do to create a hazy, speckled band across the sky. That’s not all. The Pleiades stars are caught up in a dim cloud of stellar dust or nebulosity that further softens their appearance.
A telephoto view of the Pleiades shows many more stars – much like the view in a pair of binoculars. Credit: Bob King

Each bright “Pleiad”, as they’re called, is named after a daughter of the Greek god Atlas, whose job it was to hold up the sky, and Pleione, a protectress of sailing. Say hi to Maia, Electra, Alcyone, Taygete, Asterope, Celaeno and Merope. Oh, and don’t forget the parents – they’re included too.

The Pleiades is one of brightest and closest star clusters in the sky. It contains some 3,000 stars and lies about 400 light years from Earth. From side to side the group spans 13 light years or about halfway from Earth to the bright star Vega. Like a school of fish, all the Pleiads move together as a gravitationally-bound swarm through space. Within the cluster, you’ll also find double and multiple stars including Alcyone (al-SY-oh-nee), a fine quadruple splittable in just about any telescope.
The brilliant blue-white stars in the Seven Sister Cluster reveal a cloud of interstellar dust through which the cluster is moving. The brightest patch of nebulosity surrounds the star Merope and is visible in a small telescope from a dark sky. Click to enlarge. Credit: NASA/ESA/AURA/Caltech, Palomar Observatory
Time exposure photos reveal hazy clouds of stardust swaddling the cluster. This was originally thought to be gas and dust left over from the Pleiades’ formation. Recent studies now show that the group just happens to be passing through a random cloud of interstellar dust. Starlight reflecting off minute dust grains light up the cloud a chilly blue-white, the same color as the hottest, most brilliant Pleiads.
So how many Pleiades can you see?  Atlas, Alcyone, Merope, Electra and Maia are easy. Pleione and Taygeta are tougher, and only the very keen-eyed can spot Asterope and Celaeno. When the group rides high in the south just before dawn in a dark sky you might spot additional outliers using averted vision (looking to the side and around an object instead of staring straight at it). I’ve heard reports of some observers seeing 15 to 20!
The view facing northeast around 11:30 p.m. in early September. Capella is a brilliant star in the constellation Auriga.

Take a look at this stellar treat the next night you’re out late. Enjoy the fact that you don’t have to freeze while doing so. Come November, when the Seven Sisters appear in the east as soon as it’s dark, you’ll need a warm coat and hat when you venture out for a look.

14 Responses

  1. Edward M. Boll

    The Pleiades are my favorites in binoculars. Tomorrow morning, my goal is to go out about 3:20 AM. There will be no Moon yet. Jupiter will be shining brightly. Mars is almost ready to come up. I plan to pinpoint the location of the rising of Comet ISON. I am sure that I won’t see it tomorrow but pinpointing the location will help me when I get serious to look for it. According to recent reports this morning, I am predicting a magnitude of 12. 5 on September 7. This may be bright enough to grab with a 10 inch scope.

  2. Edward M. Boll

    September 7, Comet Lemmon should be around magnitude 11.5. This is pretty remarkable for a comet that has been fading for around 6 months. I would assume that most amateurs have taken their last look at it.

    1. astrobob

      Probably not the last look for some of us. I’ve been following it all along. It was about mag. 11 two nights ago with an ~40′ tail and 3′ coma. Tail is getting faint though. L4 PANSTARRS was about 11.7 with no tail, only a slight elongation of the coma.

  3. Tim Fleming

    Pleiades is always a favorite – right up there with Orion. Something very comforting about seeing them – a constant in life. I wish us northern hemisphere folk had a Magellan cloud to enjoy.

    Thanks for your site Bob.


  4. Giorgio Rizzarelli

    I agree Pleiades are a beautiful subject at low magnification. At naked eye I usually see 4 or 5 (+Atlas), but all 7 if watching carefully (never tried Pleione).

    Another naked-eye multiple subject in that sky region, favorite of mine, is the double star Theta Tauri in Hyades: the 5′ separation is easily resolved by naked eye (which has a resolution of 1 or 2′). Interestingly Ganimede at max elongation (at Jupiter opposition) has also 5′ (and mag5); hence it can’t be seen by naked eye only because Jupiter blinds it. So next opposition let’s try to see at naked eye Ganimede by covering Jupiter with something.

    Morning sky is indeed a show in this period, with Mars and Jupiter up in the dark together with gorgeous winter constellations Aur Tau Gem Ori. Last night the two planets, with Moon and Gemini (Pollux actually), formed a “parallelogram”.

    Speaking again about Jupiter, it’s now enough high at dark to have good seeing in scope, if one has a good weather as I had yesterday. I could separate in visual (& photo) the N & NN temperate belts, which I couldn’t last year. Either I have a more exercised eye, or the bands had a little change (did you maybe heard some news about?).

    1. astrobob

      I’ve always enjoyed Theta Tau. They look so positively sharp and clear when you stare at them. Your description of Jupiter makes me eager to get out soon for a look in my scope. I plan to Tuesday morning.

  5. Edward M. Boll

    The sky at 10:20 PM seems a little weird now. There is no Moon, no naked eye planets unless you can see Uranus which is still quite low in the sky.

  6. Peter K

    Love that boulder lake photo! Is that a little meteor just left of Pleiades? Can you post a link to a higher res photo?

  7. lari

    I have been starwatching for 4 consecutive nights now enjoying the Pleiades through binoculars. The skies have been so clear! Early this morning I luckily saw 3 shooting stars! One just to the left of Cassiopia around 5:30 CT, it had a long white tail and came from the north (random leftover perseids?). The other two were in the east. The first one was just above Orion at 5:53 CT with a long white tail and the other was redish with short tail, and it looked like it came right out of Betelguese around 6:04 CT. Neat, wonder if anyone else saw them?

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