Pick out a dark place to view the Perseids

If you haven't already, now is a good time to pick out a good dark-sky place to watch what is probably the premier meteor shower of the year, the Perseids.

Meteors from the shower may be seen several evenings in advance of and following the peak day of Wednesday, Aug. 12.

Unfortunately for those of us who are not morning persons, the best viewing time will be in the hours before dawn on Aug. 12 when the leading side of the Earth will be heading face on into the meteor stream.

Comets are conglomerations of ice and dirt particles which reside in what is called the Oort Cloud, a vast region of space well out beyond the orbit of Pluto. These comets are the leftover bits from the formation of the solar system.

Occasionally a perturbation of gravity will loosen a comet and send it on a trip into the inner portion of the solar system to orbit the sun where it may be observed. Some comets have orbits around the sun in periods ranging from a few years to hundreds of years.

When comets do make the trip in, the heat from the sun melts some of the cometary ice and dust-sized particles will boil off the surface to be left in a trail or stream which follows the comet's path around the sun. When the Earth intersects one of these dust trail a meteor shower occurs.

Comet 109PSwift/Tuttle, the parent comet of the dust stream responsible for the Perseids, is a periodic comet co-discovered by astronomers Lewis Swift and Horace Tuttle in 1862. It has an orbital period of about 130 years. The most recent pass was in 1992. Orbital calculations discovered the comet has been observed for at least 2,000 years.

During the most recent pass there was some concern when initial orbital calculations indicated a possibility that the comet could strike the Earth or moon on its next pass in August of 2122.

Further investigation showed that would not be the case; however it will make a very close pass to the Earth at that time.

It is possible that this year's Perseids could produce up to 100 meteors per hour. The best place for viewing is a dark sky site away from city lights. Lay on a blanket or sit in a reclining chair where you will be able to get a whole-sky view, that way you won't miss any of the bright light streaks that make up the Perseids. After the moon goes down at 1:45 a.m., visibility will greatly improve.

SKY WATCH:

If you have a pair of binoculars check out the western horizon about a half hour after sunset to try and find bright Venus. It will be well within the glare of the sitting sun. If the glare isn't too bright check up and to the left of Venus for a line up of Regulus, the brightest star in Leo the Lion, and the planets Saturn and Mars.

On Aug. 2 an extremely thin crescent moon will join the Venus/Regulus pair. The next evening the moon will be between Saturn and Mars and on Aug. 4 a slightly thicker moon will be about 10 degrees, about the width of your fist held at arms length, to the left of Mars.

Also on Aug. 4, Venus will be in a very close pairing with Regulus, however the pair will be very, very close to the horizon and still in the bright glare of the setting Sunday, Aug. 6, will see a growing crescent moon visiting the bright star Spica, the brightest star in Virgo the Maiden constellation.

NEXT TIME:

More astronomical blathering.