Observing Calendars

March Observing Calendar   Last month we focused on Orion. Before we leave this grand constellation, we should speak to its mythology. Stellar mythology can be found deeply rooted in all of the ancient civilizations: Chinese, Egyptian, Mesopotamian, Greek, Roman, North and South American Indians, etc. So we must choose which civilization's mythology we wish to follow. I have followed the Greek characters for the most part. Orion was the offspring of Neptune and the nymph Euryale. He was gigantic in stature and strength, and so became the great hunter. He boasted that he was not afraid of any man or beast and that he may chose to eliminate all animals on earth. When Gaia, Goddess of Earth, heard this she sent the scorpion to kill him. We see Scorpion rising in the east in pursuit as Orion sets in the west. Another version goes this way: Diana, Goddess of the Hunt, fell deeply in love with Orion. Her brother, Apollo, accused her of neglecting her duties in favor of Orion... saying she could not even kill the hare rustling in the bushes near Orion. Angered by his accusations, she shot an arrow at the hare, missing and killing Orion instead. Zeus, urged by Diana in her grief, placed Orion in the stars so he would be forever memorialized. The constellation Lepus, the Hare, is placed just below Orion in tribute. Find Procyon as described last month. Scan left, toward the northeast. Find the two bright stars, one yellowish and the other white. These are Pollux and Castor, respectively, the heads of the Gemini Twins. This time of year they stand on their heads, so you must scan up toward the zenith (overhead) to visualize their bodies. Pollux is a cool star with a surface temperature of 4,500 degrees Kelvin, 35 light-years away, and about four times the diameter of the sun. Castor is actually six stars, three pairs of close binaries all bound gravitationally and circling a common center point. Follow up the torso of Castor along his left side as you are looking. Count the brightest stars starting with Castor's head. Visualize an equilateral triangle formed by the sixth and seventh stars on the right and the third point of the triangle to the left. Now scan up and down a couple of degrees roughly parallel to the two stars. You should come to M35, an open cluster containing about 75 stars. A smaller more compact cluster may be seen to the southwest. Smaller scopes will show M35 as a bright patch. Scopes of 8-inch apertures or more will reveal more detail and resolve stars in the group. Draw another imaginary equilateral triangle, this time with Pollux and Procyon toward the zenith and the third point looking down toward the horizon. You will be looking at the center of the faint constellation Cancer, the Crab. In this field of view will be M44, Praesepe or the Beehive Cluster. This is a naked-eye object and is an excellent binocular or small telescope object, aptly named for its beehive appearance on clear dark nights. It is 577 light-years away and is comprised of about 200 stars. Now follow the two stars off to the right. Jupiter may obscure the first one. This forms the right-hand arm of the "Y" in Cancer. Scan roughly two degrees up from here. You should find another open cluster, M67. This is one of the oldest galactic clusters known. Its chemistry is more like a globular cluster although it clearly is not. It is about five billion years old, the same age as our sun, and is about 2,500 light-years distant. We can't leave this month without commenting on Jupiter. It may be obscuring our view of M44 at this time. Jupiter is a fantastic sight any time, in any size instrument. One of the reasons is that it will change significantly even over a viewing period. The four major moons rotate out of view about every two and a half days. One of the exciting visual events is watching a moon disappear behind Jupiter or seeing its shadow on Jupiter's surface as it makes its transit. You will notice the several bands of darker color radiating from the equator. These are called equatorial belts. They are comprised of fast-moving clouds held in place by gravitational and centrifugal force, each rotating at different speeds. The large oval spot is a cyclonic cloud that changes size and position from time to time. As a matter of perspective, it is presently shrinking but still measures about two earth-diameters wide. Thirty-nine moons have been identified orbiting Jupiter. Saturn has 30. One hundred two moons have been found orbiting the planets of the solar system.