In October 2010, keep your eyes open for comet 103P Hartley. This comet is a fairly short period comet with an orbital period of a little under 6.5 years. This year's apparition, though, could be a very interesting one.
The 2010 apparition of comet 103P Hartley is interesting because the comet's perihelion and closest approach to Earth are so close to each other. Shown in the image to the right is the comet's close approach to Earth on October 20th, 2010. This close approach is only 8 days prior to the comet's perihelion, where it is closest to the sun. This combination could result in a 2010 apparition of 103P Hartley reaching up to magnitude 5. If we're very lucky, it may go even higher!
Once every year, the Perseid meteor shower returns. Each year, the Perseids are an excellent meteor shower, and are possibly the most popular meteor shower (they're definitely my favorite). They are often very fast and bright, and can sometimes leave fiery trails in the sky.
The Perseids are called so because of their apparent origin, called the radiant, in Perseus. Each meteor you see is actually a piece of the comet Swift-Tuttle. This comet leaves behind a trail of dust and debris every time it orbits the sun, thus refreshing the source of the Perseid meteor shower. This year's Perseid meteor shower will be at its most active peak on the night of August 12th, 2010.
The Perseids can be viewed any time between now and the 24th, however, since their peak is so broad. Look to the North and Northeast to see the most meteors. This year's shower also has the benefit of having very little interference from the Moon. The best time to watch the meteor shower is after midnight, as the Earth is rotating into the shower in the predawn hours. This will increase the meteor rate considerably.
With good, dark skies (after the moon sets at about 10 PM), expect up to 100 meteors per hour. Of course, light pollution and moonlight may decrease your observed meteor count.
Viewers and amateur astronomers in the northern US may be treated to a special event tonight and tomorrow night. The sun recently emitted a solar flare in the Earth's direction.
While this has been quite rare lately, this one is poised to put on quite a light show in the Earth's upper atmosphere. When the charged particles from this solar flare reach the Earth, their energy is turned into light by the Earth's upper atmosphere. We know these as the aurora borealis.
So tonight (August 3rd) and tomorrow (August 4th), look high in the sky at dusk and into the night to see a possible aurora display in your town! Current estimates are a 45% chance of activity with a 10% chance of significant geomagnetic activity. Pretty good odds considering!