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The Herdsman, Napoleon, and the Kangaroo
updated: Jul 12, 2014, 11:00 AM
By Chuck McPartlin
Sorry, everyone. I admit that I caused the cloudy conditions on the Fourth of
July that detracted from the fireworks displays. Setting up a telescope just
seems to do that. I was hoping to get images of the close approach, from our
point of view, of the large asteroids Ceres and Vesta, which I'll cover in a
future article. With clouds illuminated by the First Quarter Moon covering
most of the sky, I had to go for some astronomical goodies that were almost
directly overhead, in the constellation Böotes, the Herdsman.
If you follow the curve in the tail of Ursa Major, the Great Bear, which also
forms the handle of the Big Dipper, you can "arc to Arcturus", a prominent
reddish star. Arcturus comes from the Greek for "Guardian of the Bear", and
forms the base of Böotes, which to me looks like a giant ice cream cone. To
the Greeks, the Herdsman and his Hunting Dogs, Canes Venatici, were chasing
the Bear around the North Pole, keeping the stars rotating around the sky.
Here's how they are depicted in Starry Night Pro:
Arcturus is about 37 light years away, and is a red giant star nearing the
end of its life. It's only slightly more massive than the Sun, so it will
eventually poof out a planetary nebula and collapse into a white dwarf. It
is the brightest star in the northern hemisphere summer sky.
Böotes is home to a couple of fun asterisms, groupings of stars that make
recognizable patterns in the sky. We've previously seen some winter asterisms,
but there are plenty in the Santa Barbara's summer skies, too.
Right next to Arcturus is a little arc of stars that form an asterism known
as Napoleon's Hat. It's just a chance alignment of stars at different distances.
It's visible in binoculars if you keep the glare of Arcturus out of the field
Up in the scoop of ice cream is another asterism that may be overhead, but comes
from Down Under. This one is the Kangaroo. Once again, it's a chance arrangement
of stars between about 200 and 16,000 light years away that looks a bit like a
hoppy marsupial. This one's a little too dim for binoculars.
There are many more asterisms to hunt down on clear summer nights, so stay tuned!
References for a Cloudy Evening
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