OCCULTATIONS OF PLANETS BY THE MOON in 2007

The Moon occasionally hides bright stars and planets as it moves around the Earth. Near the time of an occultation, when the moon and the planet are both visible in a small telescope, you can actually see the Moon move eastward in its orbit around the Earth. These events are visible within bands on the Earth that are about 2100 miles wide (the Moon's diameter). Great chance for an interesting photo if the Moon's glare doesn't wash it out.

See list at IOTA

METEORS

The flash of a meteor is caused by a fragment, often no larger than a fingernail, descending through the atmosphere at speeds of ten to fifty miles per second. We see them at heights of about fifty miles, and they seldom reach the ground.

WHAT IS A METEOR/SHOOTING STAR?

It lasts only a second or so, and in that brief time it can move half way across the sky. These streaks of light are produced by small bits of dirt entering our atmosphere at speeds of 10 to 40 miles a second (36,000 to 140,000 miles per hour). At that speed you could fly from New York to London in 3 minutes.
By photographing them from the ground, astronomers have found they burn up at heights of 20-50 miles. Some of the fragments are debris from the tail of a comet, left behind as the comet evaporates in the sunlight. When the earth plunges through the path of a comet, we see a shower of meteors, such as the Perseids, the Leonids or the Geminids. During a shower (which last for hours or days) the meteors can appear at a rate of dozens per minute, but a more common rate is one per minute. These showers are named for the constellation they appear to stream from. Some of the fragments are probably left over from the early days of the solar system, when the planets were being formed. These produce "sporadic"meteors which can be seen any time of year at a rate of about one per 5 minutes or so.
The body of a meteor is called a meteoroid. If you want to see what a meteoroid might look like, make a snowball and smash it against a tree. The flying fragments are roughly the size of a meteoroid. But they are much slower. If you could shoot a fragment at a speed of 36,000 mph, it would glow from the heat of air friction and you would have a meteor in your yard.

TWO TYPES OF METEORS

Meteors come in two varieties: "sporadic" and "shower." On every dark night of the year, it is possible to see a sporadic, or random, meteor every few minutes. There is no telling where the next will appear, because they are scattered through the solar system and presumably are fragments left over from the formation of the planets. Occasionally a very large fragment will produce a "fireball," remaining visible for hundreds of miles and crashing to earth as a meteorite. Meteor "showers" are produced by swarms of cometary debris that follow their parents about the sun. Every comet produces such a swarm, but we encounter only a few of them. When we do, the meteors appear to fan out from a single point in the sky. This is the "radiant," and the shower is named for the constellation or star near that point. On the night of a shower, hundreds of meteors may be seen in a few hours.

METEOR SHOWERS

This table lists the best showers. They appear on the same date each year, because their orbits are fixed in the solar system. The last two columns of the table indicate how the moon light will impair the visibility of the meteors. Within a few days of full moon is considered "bad," new moon is "good" and the time of first and third quarter are "fair".

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THE MOST INTENSE METEOR SHOWERS

NAME	DATES	MAX HOURLY RATE	COMET	MOON: 2007
Quadrantids	Jan. 3,4	50	?	Poor
Eta Aquarids	May 1-9	20	Halley	Poor
Delta Aquarids	July 25-30	20	?	Fair
Perseids	Aug. 10-14	50	1862 III	Good
Draconids	Oct. 10	Variable	Giacobini-Zinner	Good
Orionids	Oct. 18-24	20	Halley	Good
Leonids	Nov.14-20	10	Temple	Good
Geminids	Dec. 10-14	50	?	Good
Ursids	Dec. 19-25	15	Tuttle	Poor

LOOKING FOR METEORS

Little is gained by looking for meteors with binoculars or telescopes because such devices restrict your field of view. The most important precautions are to find a place where the sky is dark and there are few obstructions and to let your eyes become dark adapted for at least 15-20 minutes. It is true of most showers that the rate of appearance will increase after midnight, so try to stay up late -- or set your alarm for about 2 or 3 in the morning. Finally, be patient. Even the flashier showers (producing 50 meteors/hour at maximum) only give a meteor every few minutes on average. The fun comes in trying to identify the radiant -- the point in the sky from which they all seem to radiate. And in catching the occasional biggy.

PHOTOGRAPHY

Photography is not difficult. Use fast film and open the lens as far as possible. Then leave the shutter open for a half-hour or so. (In other words, you cannot do this with a typical point-and-shoot camera. You need one which permits full control of the shutter. Make sure the flash is disengaged; it will only interfere, unless you want some special effects, such as trees in the foreground.)

AVOID THE MOON

Moonlight is a definite hindrance (and will make such photography practically impossible), so it is best to look for meteors when the moon is not up. The last row of the table above will help you to select the showers.that are least hindered by the moon.