Download PISGAH Dr. Bob Hayward ASTRONOMICAL Astronomer/Educator

PISGAH
ASTRONOMICAL
RESEARCH
INSTITUTE
Dr. Bob Hayward
Astronomer/Educator
Graphics from TheSky
Software Bisque
Mountain Skies
February 22, 2016
JUPITER MOVES INTO THE EVENING SKY
The planets: With no planets in our evening sky for the past month, we are eager to see a few
of these beautiful objects both visually and with our telescopes. Things are quickly changing for the
better in this respect. Due to the motion of the earth around the sun, Mars, Saturn and Jupiter are
rising earlier each month and, one by one, we will soon be seeing them before a normal bedtime.
Jupiter is already there, in fact, as it rises at 7:30 p.m. this evening. As the second brightest of the
planets (after Venus, now our “Morning Star”), we could call Jupiter our “Evening Star.” Keep an eye
on it and particularly note it on Saturday evening when it is just to the north of the still nearly full moon.
Mars follows Jupiter by rising a few minutes before 1 a.m. It is getting brighter as we approach
it in our orbit around the sun and its red color will become more apparent. The beautiful ringed planet
Saturn is now rising before 2:30 a.m.
So, if you think about it, we have three planets rising
successively throughout the night. This means in the predawn hours they are lined up across the sky.
There, they are joined by Venus and Mercury so, as for the past month, we have had all five of the
classical planets in the east before dawn. Mercury is the lowest and most elusive and, while it is still
visible low in the morning twilight, it is getting harder to spot it. Tomorrow morning it rises less than an
hour before the sun and it passes behind the sun in superior conjunction only a month from tomorrow.
So, with Mercury low in the southeast, use Venus up and to the right of it as a guide. Venus is the
brightest of the planets and, even though it is getting lower each morning itself, it is much easier to spot
than Mercury. By the end of the month Mercury will be too close to the sun for observation.
Now, look up to the south for the other three planets. First, above and to the right of Venus is
Saturn near the bright star Antares. Farther up is the red planet Mars. Then a bright stars pica. And
finally, a bit to the west of due south is the bright planet Jupiter. Happy observing!
The stars: The bright stars of the winter skies are now becoming even more apparent. Orion
the hunter can be found in the east as the sky darkens and serves as the central figure for our
observing. Locate his belt marked by three bright stars in a row. Now, draw a line through his belt
towards the west and you will come to a bright star, Aldebaran, the eye of Taurus the bull. A cluster of
stars called the Hyades forms the face of the bull and can be seen in the form of a letter “V” with
Aldebaran at the top of one side of the “V.” Technically, Aldebaran is not a member of the Hyades but
rather a foreground star, one in front of the Hyades.
Go back to the belt of Orion and draw a line to the east. Rising in the southeast is a bright white
star. This is Sirius the Dog Star. While Sirius appears to be the brightest star in the nighttime sky, it is
not intrinsically the brightest nor is it the closest to us. But it is a combination of both so that it appears
to be the brightest; it is a white-hot star that is a little less than nine light years away, close as stars go.
Sirius was known as Sothis to the ancient Egyptians and was a very important star to them because,
when it rose just before the Sun, called a “heliacal rising,” it foretold the pending flood of the Nile River.
It also gives rise to our term “dog days of summer.”
To the north of the great dog Canis Major lies the dimmer but still quite noticeable star Procyon.
As the risings of Sirius and Procyon are
observed
from
mid-northern
latitudes,
Procyon comes up just before Sirius; thus,
Procyon
means
“He
who
Procyon is the brightest
precedes.”
star
in the
constellation of the little or lesser dog,
Canis Minor, sometimes dubbed “The Pup.”
There is only one other moderately bright
star
in
Canis
Minor
and,
thus,
the
constellation looks less like a puppy than a
hot dog. A triangle formed by the red star
Betelgeuse in the shoulder of Orion with
these two dog stars, Sirius and Procyon, is
known as the Winter Triangle.
Celestial Calendar:
February 22, 1:20 p.m. EST – Full Moon
March 1, 6:11 p.m. – Last Quarter Moon
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PARI is a public not-for-profit public foundation established in 1998. Located in the Pisgah National
Forest southwest of Asheville, NC, PARI offers educational programs at all levels, from K-12 through postgraduate research. For more information about PARI and its programs, visit www.pari.edu. Follow PARI on
Twitter at http://twitter.com/Astronomy_PARI. “Like” PARI on Facebook at
www.facebook.com/Pisgah.Astronomical.Research.Institute.
For further information or questions about this Mountain Skies column, contact Dr. Bob Hayward at
[email protected]. Graphics produced with TheSky Astronomical Software, Software Bisque.