The photo at the top of this page is a halo around the Hunter’s Moon on October 29, 2012, as seen by EarthSky Facebook friend Randy Miller in Anderson, Indiana.
The October full moon – the Northern Hemisphere’s Hunter’s Moon – came to pass last night (October 18/19). In a bit of misfortune for meteor-watching enthusiasts, the full Hunter’s Moon happens only a few days before the expected peak date for the Orionid meteor shower.
Although the Orionids will be bombarding the nighttime from midnight till dawn for the next few nights, the light from the bright waning gibbous moon is sure to wash out all but the brightest Orionid meteors. The most meteors are expected to fall in the wee hours before dawn on Monday, October 21. On a dark, moonless night, the Orionids can produce up to 25 meteors per hour, but only a fraction of this number can be seen in the bright moonlight in 2013. But if you’re game, give it a go anyway, as seeing even one meteor can be quite a thrill.
The moon will look plenty full tonight, as it lights up the nighttime again tonight from dusk till dawn. In fact, the moon will appear big and bright all through the peak nights of the Orionid shower. What’s more, the moon will be out from early evening from sunrise, to put a real damper on this year’s Orionid meteor shower. The waning moon following the full Hunter’s Moon rises sooner than usual in the evening, and moreover, shines higher than usual in the western sky during the predawn hours. The Hunter’s Moon double-whammy makes 2013 a tough year for the Orionid meteor shower. But even if you don’t catch many Orionids, chances are that you’ll see the constellation Orion – the radiant of the Orionid meteor shower – on this moonlit night. Orion rises in the east at late evening, fairly close to midnight.
The radiant point for the Orionids is in the northern part of Orion, near Orion’s club. Many see the Hunter as a large rectangle. You’ll surely notice its distinctive row of three medium-bright stars in the middle: those stars represent Orion’s Belt. The brightest star in the sky, Sirius, is to the southwest of Orion on the sky’s dome, and the Belt stars always point to Sirius. This constellation is up in the southeast in the hours after midnight and it’s high in the south before dawn. We will have much more to say about Orion in the months to come, because it’s one of winter’s most prominent constellations.
Do you need to know Orion to see the meteors? Nah. The meteors appear in all parts of the sky. But if you trace the paths of the meteors backwards, you’ll see they all seem to come from single point within Orion. The radiant point for the Orionids is above and outside Orion’s rectangle. But – again – you don’t need to identify exactly where the radiant is to enjoy the meteors, or Orion! Just go to a dark sky and look up.
When should you watch for Orionid meteors in 2013? The best time for viewing for these fast-streaking Orionid meteors will be between midnight (1 a.m. daylight time) and dawn on the mornings of October 20, 21 and 22, 2013. That time holds true no matter what time zone you’re in. If you’re in Asia, you might want to lean a bit toward the morning of October 22.
What planets are visible at late night? The planet Jupiter rises in the east at late evening, and the planet Mars rises in the east in the wee hours after midnight. Dazzling Jupiter beams to the northeast of Orion in October 2013, near the constellation Gemini’s two brightest stars, Castor and Pollux. The planet Mars shines close to Regulus, the brightest star in the constellation Leo the Lion.
Where do the Orionid meteors come from? Earth crosses the orbit of the famous Comet Halley every year in October. The meteors are debris from this comet that enter Earth’s atmosphere and vaporize as they fall.
How many meteors can you expect to see? The number will vary greatly depending on when and where you watch. Meteor showers are not entirely predictable. That’s the fun of them! At most – on a moon-free night – you might see about 25 meteors per hour, or one meteor every few minutes. Although no moon-free night greets the 2013 Orionid meteor shower, watching even one bright meteor can make for a memorable night. Have fun.
Bottom line: The 2013 Orionid meteor shower is expected to peak on Monday, October 21, in the hours between midnight and dawn. However, the light of the bright waning gibbous moon will wash out all but the brightest Orionid meteors.