Observing Calendars

July Observing Calendar:   This month we are going to look further south to the constellation Scorpius, the Scorpion. Reference to the constellation Scorpius can be traced back to the Mesopotamian era. References can be found in Babylonian, Sumarian, and Assyrian texts as far back as 2500 BC. Greco-Roman mythology has the Scorpius biting Orion on the heel. Look southeast low on the horizon. Locate the three fairly bright stars forming an arch-like pattern and a bright reddish-orange star down toward the horizon near the center of the three star arch. The reddish-orange star is Antares, and is very low on the horizon now. Antares is actually a close double star. Its Greek name means "rival of Mars" because of its reddish color like Mars. Find the dimmer star just above Antares. Between Antares and this star is a bright but rather small globular cluster, M4. M4 is an easy target for small scopes and binoculars. It is estimated to be 6,500 light-years distant. Move about halfway between these two stars and slowly scan south, or to the right to find it. Now return to marker star above Antares. Find the topmost star of the three star arch forming the head of the Scorpion. Notice the dim star to the left and below the bright star. Draw an imaginary line between the two dim stars. Scan slowly along the line and about halfway between them, you should find another globular cluster M80. Easily seen in small scopes and binoculars, it is estimated to be 28,00 light-years away. When we view Scorpius, we are looking toward the center of our galaxy. We are on the interior edge of the Orion-Cygnus Spiral arm. We look through the interior stars of this arm and through the interior stars of the Sagittarius-Carina Arm to the center of the Milky-Way. On August 26-27, Mars will be the closest to earth in 60,000 years. This is a heads-up to those interested in preparing for a Mars observation or imaging session. Check Sky & Telescope magazine June issue for details.