October skies rife with plenty of planetary activity
This month most of the planet watching will be concentrated around early evening or early morning hours. Venus brightens to an incredible magnitude of -4.5 as it hangs about 10 degrees above the southwestern horizon in the early evening hours. A special treat will be on the 16th when Venus will be only 1.5 degrees above the bright red star Antares in the constellation Scorpius.
Saturn is edging ever closer to the southwestern horizon. By mid-month binoculars will be needed to pick it out of the afterglow of sunset. Mercury puts in a brief evening sky visit early in the month. Even though it is brighter than Saturn it will be closer to the horizon and therefore you will probably need binoculars to find it.
The best opportunity will be on the 7th. Point your binoculars toward the southwest horizon and to the lower right of the crescent Moon. You might get lucky and see both Saturn and Mercury hanging just above the horizon with Saturn being about 5 degrees above Mercury.
Jupiter rises around midnight on Oct. 1 and two hours earlier by the end of the month. It also brightens to magnitude -2.4. Jupiter reaches quadrature, 90 degrees west of the Sun on the 12th. Because of the lighting angle with the Sun, this is a great time to view the shadows of the 4 large Galilean moons as the shadows transit the surface of the planet. To view these transits you will need a moderate sized amateur telescope.
Mars rises about 4 to 5 hours before the sun and spends most of the month hanging out in the constellation Leo, “the Lion.” About one hour before dawn on the 14th, Mars will be only one degree above the bright star Regulus. While all this is happening, a third object will be hurrying to join Mars and Regulus, Comet ISON.
During October, Comet ISON will brighten from magnitude 10 to magnitude 7, still too faint to be seen with the naked eye. It will pass 2 degrees north of Regulus on the 16th and should be visible through a good pair of binoculars or a small telescope. Mars and ISON will track along about 1 degree apart from the 16th through the 19th.
The Moon will be new on the 4th, first quarter on the 11th, full on the 18th, and last quarter on the 26th. Looking east on October 1st, about one hour before sunrise, the waning crescent Moon will be just below and to the right of Mars. Around 6 a.m. on the 25th and 26th, looking high in the southern sky, the waning Moon will bracket Jupiter in the constellation Gemini, “the Twins.”
Turning our attention to the west-southwest on the 7th through the 9th, a waxing crescent Moon will pass just above brilliant Venus as it climbs into the evening sky.
This year marks the 20th anniversary of the Enchanted Skies Star Party. It will be held from Oct. 2 through 5 in Socorro, New Mexico. We’re pulling out all the stops this year and we have an exciting lineup of events. Go to www.enchantedskies.org to preview events and for on line registration.
Jon Spargo is president of the New Mexico Tech Astronomy Club.