As the sun begins to set, if you look straight up into the sky, you will see a bright object shining. That's not the first star of the night; what you're seeing there is the giant gas planet, Jupiter.
Jupiter is currently in the constellation Gemini near the star Mebsuta (Epsilon Geminorum). Mebsuta is part of the outstretched leg of Castor. This dim star -?compared to other stars nearby -?is a supergiant at approximately 840 light years away. It is 8,500 times more luminous than our own sun, and about 105 to 175 times its radius.
This star is outshined by the light reflecting off of Jupiter because Jupiter is much closer to us than the star it is dominating. Jupiter won't be there for long as it slowly makes its way to another star in Gemini, Wasat (Delta Geminorum).
By the end of March, Jupiter will be between Wasat and Mebsuta. Wasat is part of the waist of Pollux, but there is more to Wasat than just a simple little star that is again being outshined by Jupiter.
First off, Wasat was only 0.5 degrees to the west of Pluto in 1930 when Clyde Tombaugh discovered the tiny once-planet now a dwarf planet. Wasat is approximately 60.5 light years away, and it is predicted that within 1.1 million years, the star will come within 6.7 light years of our very own sun.
Wasat isn't just a single star either, it is a triple star system with a binary pair of stars orbiting each other with a period of 6.1 years, and those two orbiting the primary star with a period of 1,200 years. These should be possible to spot with a small telescope and high magnification.
Now that we have examined Jupiter and two interesting stars in Gemini, let's have a look toward another planet. Around 10 p.m., you can spot Mars low on the eastern horizon in the constellation Virgo.
You may remember last year around this time we were watching Saturn rise with Virgo. Saturn has now moved into Libra, but Mars is close to where it was last year, currently about 5.5 degrees northeast of the bright star, Spica.
Spica is the brightest star in Virgo and is Latin for "Virgo's ear of grain." If you look at drawings of the constellation, Virgo is holding an ear of grain right where Spica is located. Spica is approximately 260 light years from our solar system and is a double star. It's companion is not visible.
Spica is massive enough to become a supernova in the future, but I wouldn't count on that happening in our lifetime. The Greek astronomer and mathematician Hipparchus measured the position of Spica relative to the Autumnal Equinox around 127 BCE, noted its shift compared to earlier measurements and thus discovered the precession of the equinoxes. Nicolaus Copernicus also made numerous observations of Spica while researching precession.
Around midnight, Saturn starts to climb above the horizon in the constellation Libra. About 2.5 degrees east of the ringed planet is the star Zubenelakrab (Gamma Librae). Zubenelakrab is approximately 152 light years from the solar system and about 71 times more luminous than our sun.
The brightest star making up the constellation of Libra is Zubeneschamali (Beta Librae) and it is approximately 185 light years from the solar system. Zubeneschamali is a blue-white dwarf and spins at a high speed of 250 km per second. I can't go through this without writing about my favorite star name, Zubenelgenubi (Alpha Librae) which is the second brightest star in Libra.
Zubenelgenubi is a binary star whose companion, slightly above and right of it, should be visible to those with keen eyesight and visible to the rest of us in binoculars. Really though, the most interesting thing about Libra this year is Saturn. I highly suggest if you have a pair of binoculars or a small telescope to aim at Saturn and have a look. Saturn's rings are still tilted towards us giving it a nice view of the rings, and with enough power behind your telescope, you may be able to make out the Cassini Division, which is a large gap between two of the most prominent parts of the rings.
Whether you're staying up all night or waking up early in the morning, you will most likely spot a bright object rising above the horizon around 4:30 to 5 a.m. This is actually the planet Venus.
Venus is in the constellation Capricornus, but it's so low on the horizon that not much of the constellation will rise before the dawn washes out all the stars. Venus never fails to impress all by itself, though; it is so bright that it's hard to miss, even with a little bit of cloud cover. This is another interesting sight to view in your small telescope or binoculars. With some magnification on your telescope you can be sure to see that Venus doesn't appear as a round ball like the other planets I have mentioned so far. It cycles through phases just like our moon, albeit a bit slower. The planet can go from looking almost completely full, to becoming a thin crescent shape as it orbits around the sun getting closer between the Earth and the sun. This is what causes the phases.
If you have this with you on a long night of observing, have a look around the sky while you wait for the next planet to rise. You could easily stumble upon many great objects to look at such as nebula, galaxies, and star clusters. It's easy to get lost in space from you own backyard.
With our roll-off roof facility up and running, astronomers of the Adirondack Public Observatory are eager to dazzle you with telescopic views of planets and cosmos every first and third Friday of the month (next on Friday). Go to the APO website at apobservatory.org and click on "events" for more information and directions to our site above Little Wolf Pond in Tupper Lake. Listen for Aileen O'Donoghue on North Country Public Radio about once a month during "The Eight O'Clock Hour" or email her with any questions at firstname.lastname@example.org.