Observing Highlights for October: A Penumbral Lunar Eclipse and the Approach of Comet ISON
A penumbral lunar eclipse can be a trick to see. Unlike a "regular" lunar eclipse, the moon never passes into the darkest part of Earth’s shadow, and therefore the dimming of the moon is slight and difficult to detect.
For those in the United States, a penumbral eclipse will already have begun on October 18 as the full moon rises. The farther east you are, the more likely it is that you’ll see a change in the Hunter’s Moon. The event will end soon after moonrise.
Observers are eagerly awaiting the appearance of Comet ISON, which will put on its best show in November and December. But for those who want to get an early peek, get up before sunlight in mid-October and look east-southeast. Regulus, the brightest star in Leo, and reddish Mars will be just one degree apart on October 14, with Mars about one degree above and to the left of Regulus. Use binoculars or a telescope to look the same distance and direction above Mars to find Comet ISON.
The three objects will be similarly close together on October 15, and then Mars and ISON sink below Regulus. By October 20 ISON will start to speed away from the Red Planet as it heads toward the sun.
Three planets are in the southwest after sunset, but Venus is the one that will draw all eyes. It blazes at magnitude -4.3, easily overcoming the twilight's glow. But Saturn and Mercury, to Venus’s right, have a harder time. Try to find them on October 6 when a crescent moon lies between the two planets. Saturn will be above and Mercury will be below the moon.
If it’s cloudy, try the next night, October 7, when the moon is about halfway between Venus, to the left, and Mercury and Saturn, to the right. On October 8, the moon has moved off to above Venus, and Mercury and Saturn come within five degrees of each other, but they separate from here after and sink toward the sun.
The Orionid meteor shower peaks in October on the evening of 20th overnight to the 21st, but with the moon just past full it will wash out the fainter shooting stars. The Orionid meteor shower is a product of Halley's Comet and can produce 25 meteors an hour.
(Photo: Jupiter among the winter constellations. Credit: John Chumack.)
Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She writes the SkyGuide for AstronomyToday.com. You can follow her on Twitter at twitter.com/Astronomommy.