Observing Calendars

February Observing Calendar   The winter constellations are in full glory. The Gemini Twins are beginning their trek up the northeast horizon. The Big Dipper, Ursa Major, is standing on its handle in the northeast. Saturn is high in the southeast, an excellent viewing position. Jupiter is approaching good viewing in the northeast. Orion, magnificent at any time, is high in the zenith to the south, another prime viewing position. We will focus on Orion, The Hunter. From our vantage point, Orion appears to be reclining, suspended between the north and south celestial poles with his belt pointing almost perpendicular to the horizon. Betelgeuse, the bright orangish giant star just below Aldebaran, is a supergiant. It is about 590 light-years distant and nearly a billion miles in diameter. If it were the center of our solar system, it would nearly cover the orbit of Jupiter! However, its average density is less than one ten-thousandth the density of our atmosphere. This is the great hunter’s right shoulder as he faces us. Scan south to the three bright vertical stars forming the belt. Travel about the same distance further south and you come to the bright companion, Rigel, Orion's right knee. Rigel, also a supergiant star, is the seventh brightest star in our sky. Rigel is actually a binary star, meaning there are two stars that orbit each other. Go back to Betelgeuse. His left shoulder, Bellatrix, is the second brightest star in the triangle you see anchored by Betelgeuse. Let’s continue our orientation to the sky for a moment. Draw an imaginary line starting with Bellatrix through Betelgeuse. Continue left to the eighth brightest star in our sky, Procyon, in the constellation Canis Minor and named the Little Dog. Procyon, named in ancient Greece, means "Before the Dog," referencing its arrival in the heavens before Sirius. It is estimated to be about 11 light-years away, which partially explains its brightness. Visualize a line from Procyon to Cappella (see December), and you will pass through the knees of the Gemini Twins, Pollux, and Castor. Draw another line down from Orion's belt. The bright star you see is Sirius, the anchor star in Canis Major, the Big Dog. Sirius, known as the "Dog Star" or "Nile Star," is the brightest star in our heavens. It, Procyon, and Betelgeuse form the Winter Triangle. Canis Major is a rich portion of the sky for clusters, double stars, and nebula. Spend some time with a pair of binoculars or a small telescope. It's worth it! Now that we’re oriented, let’s focus on the many wonders to be found in Orion. Start with M42, (click here for image- return by using Back button on Browser) the Great Orion Nebula, just to the right of the bottom and middle star in the belt. This blurry streak is usually identified as Orion’s sword. It is awe-inspiring in binoculars or the smallest of instruments. This exceptionally rich, star-generating engine covers one square degree, four times the size of the moon, and is about 1,600 light-years away. The entire constellation is blanketed in a cloud of molecular soup composed primarily of hydrogen. The center star in the nebula is a very young, hot star. The energy emitted by this star causes the gases in the cloud to become excited and throw off electrons, hydrogen ions, and photons (visible light, in this case in the red spectrum). These atomic materials in turn are re-captured to build new stars. There are four very young stars in the center "bright spot" of the nebula. They are called the Trapezium, and are believed to be less than 100,000 years old. More than 100 other new stars are growing in this star incubator! M43 is just below the M42 image, and its nebulosity is surrounding one star. The dark space between them is actually stellar material obscuring the light from our view. The dark ridges flowing up the right-hand fan illustrate this quite well. It, too, is estimated to be 1,600 light-years away. NGC 1980 is partially seen in the upper right-hand corner. This is actually a cluster of some 30 stars embedded in more nebulosity. Now move from the bottom star of the belt on a line toward Betelgeuse. About two or three degrees toward Betelgeuse, position your field of view toward the horizon. You should see another star surrounded by more nebulosity. This is M78. There are many other worthy targets in Orion. Spend time browsing The Hunter. You won't be disappointed!