July 11, 2007: Got a calendar? Circle this date: Sunday, August 12th. Next to the circle write "all night" and "Meteors!" Attach the above to your refrigerator in plain view so you won't miss the 2007 Perseid meteor shower.

"It's going to be a great show," says Bill Cooke of NASA's Meteoroid Environment Office at the Marshall Space Flight Center. "The Moon is new on August 12th--which means no moonlight, dark skies and plenty of meteors." How many? Cooke estimates one or two Perseids per minute at the shower's peak.

Above: A Perseid fireball photographed August 12, 2006, by Pierre Martin of Arnprior, Ontario, Canada. [Larger image]

The source of the shower is Comet Swift-Tuttle. Although the comet is nowhere near Earth, the comet's tail does intersect Earth's orbit. We glide through it every year in August. Tiny bits of comet dust hit Earth's atmosphere traveling 132,000 mph. At that speed, even a smidgen of dust makes a vivid streak of light--a meteor--when it disintegrates. Because Swift-Tuttle's meteors fly out of the constellation Perseus, they are called "Perseids."

Note: In the narrative that follows, all times are local. For instance, 9:00 pm means 9:00 pm in your time zone, where you live.

The show begins between 9:00 and 10:00 pm on Sunday, August 12th, when Perseus rises in the northeast. This is the time to look for Perseid Earthgrazers--meteors that approach from the horizon and skim the atmosphere overhead like a stone skipping the surface of a pond.

"Earthgrazers are long, slow and colorful; they are among the most beautiful of meteors," says Cooke. He cautions that an hour of watching may net only a few of these--"at most"--but seeing even one makes the long night worthwhile.

As the night unfolds, Perseus climbs higher and the meteor rate will increase many-fold. "By 2 am on Monday morning, August 13th, dozens of Perseids may be flitting across the sky every hour." The crescendo comes before dawn when rates could exceed a meteor a minute.

For maximum effect, Cooke advises, "get away from city lights." The brightest Perseids can be seen from cities, he allows, but the greater flurry of faint, delicate meteors is visible only from the countryside. Scouts, this is a good time to go camping.

Above: The eastern sky, viewed during the hours before sunrise on Monday, Aug. 13, 2007.

And there's a bonus: Mars. In the constellation Taurus, just below Perseus, Mars shines like a bright red star. Many of the Perseids you see on August 12th and 13th will flit right past it. Instead of following the meteor, you may find you have a hard time taking your eyes off Mars. There's something bewitching about it, maybe the red color or perhaps the fact that it doesn't twinkle like a true star. You stare at Mars and it stares right back.

Earth and Mars are converging for a close encounter in December 2007. NASA is taking advantage by launching a new mission to Mars--the Phoenix Lander. Phoenix will touch down on an arctic plain where it can dig into the ground and investigate layers of soil and ice, searching for, among other things, a habitable zone for primitive microbes. The launch window opens on August 3rd, so by the time the Perseids arrive Phoenix may be hurtling toward the Red Planet. Landing: late Spring 2008.

It's something to think about at four in the morning, with Mars rising in the east, meteors flitting across the sky, and a summer breeze rustling the legs of your pajamas.

Maybe you should go circle your calendar again.

Author: Dr. Tony Phillips | Production Editor: Dr. Tony Phillips | Credit: Science@NASA

____________________________________________

Web Links

NASA's Future: The Vision for Space Exploration

Source: Science@NASA

For Northern Hemisphere skywatchers, August is usually regarded as "meteor month," with one of the best displays of the year reaching its peak near mid month. That display is, of course, the annual Perseid meteor shower.

This year experts predict an excellent Perseids display, as peak activity will coincide with a new moon, meaning dark skies that allow the meteors to shine.

Meanwhile, there are other lesser-known summer meteor displays to check out right now

In general, the Earth encounters richer meteoric activity during the second half of the year. And you're more likely to see twice as many meteors per hour in the predawn hours as compared to the evening hours. During the pre-midnight hours we are on the trailing side of the Earth as it moves through space. Any meteoric particle generally must have an orbital velocity greater than that of the Earth to "catch" us. After midnight, when we have rotated onto the Earth's leading side, any particle that lies along the planet's orbital path will enter our atmosphere as a meteor.

In these head-on collisions, meteors hit our atmosphere at speeds of 7 to 45 miles per second. Their energy of motion rapidly dissipates in the form of heat, light, and ionization, creating short-lived streaks of light popularly referred to as "shooting stars."

Summertime meteors are especially noticeable between mid-July and the third week of August. And between Aug. 3 and 15, there are six different minor displays. When they run (and peak):

Reserve the overnight hours of Aug. 12-13 for observing the Perseids, which under clear, dark skies will produce one or two meteors every minute.

Southern Delta Aquarids, July 12-Aug. 19 (July 28), 15 per hour, faint, medium speed.

Alpha Capricornid, July 3-Aug. 15 (July 30), 4-5 per hour, slow, bright, a few fireballs.

Southern Iota Aquarids, July 25-Aug. 15 (Aug. 4), 1 to 2 per hour, faint, medium speed.

Northern Delta Aquarids, July 15-Aug. 25 (Aug. 8), 1 to 4 per hour, faint, medium speed.

Kappa Cygnids, Aug. 3-Aug. 25 (Aug. 18), 1 to 3 per hour, slow moving, sometimes brilliant.

Northern Iota Aquarids, Aug. 11-31 (Aug. 20), 1 to 3 per hour, faint, medium speed.
go

I read somewhere that September 1st will be a great night for watching in the northern hemisphere........But, I will be watching as many as I can, thanks for the info!!

7 August 2007

Shooting stars are seen on Earth as our planet enters a dust cloud ejected by a comet, in this case, Swift-Tuttle. The dust burns up as it enters the atmosphere creating natural fireworks in the night sky.

Credits: ESA (D. Koschny)

As the Perseid meteor shower becomes visible in all its glory on 13 August, natural fireworks will fill the sky.

Showers of meteors, or ‘shooting stars’, appear as bright streaks of light in the sky. The display runs through the night.

Dust trails are left behind by every comet as it nears the Sun. As Earth’s orbit crosses the dust ejected by the comet Swift-Tuttle, a regular occurrence every August, it provides a fabulous spectacle for viewers on Earth. As the particles enter the atmosphere, they burn up, producing the fireworks. This phenomenon, called the ‘Perseid’ meteor shower, gets its name from the constellation Perseus, from where the shooting stars seem to come.

This year the Perseids are visible from 17 July to 24 August. One or two per hour can be seen at the start, increasing to about five to ten per hour in early August. The display will be at its maximum before sunrise on 13 August, when 80 to 100 meteors should be visible every hour, weather permitting.

The best time to go observing is during the pre-dawn hours of 13 August. The occurrence of a new Moon on 12 August will make for perfect observing conditions.

Even if the sky may not be totally clear, you can expect to see tens of meteors in the sky from all over Europe. The display will be on all night, starting from about 23:00 CEST on 12 August, peaking before sunrise on the 13th. This year, as a bonus, Mars is visible as a bright red dot in the East, after midnight.

Telescopes or binoculars will not be necessary as the shower is visible with the naked eye. It is important to be in a dark area, without much smog, pollution or illumination. Do make yourself comfortable – use a reclining chair or spread a blanket on the ground. The shooting stars will appear all over the sky, you need not look in a particular direction. Just make sure your eyes can adapt to dark.

This constellation map shows the constellation Perseus, from where the Perseid meteor shower can be seen arising in the sky. This year, as a bonus, Mars is visible as a bright red dot in the east, after midnight.

Credits: ESA - G. Barentsen

The Meteor Research Group at ESA is performing coordinated observations at several locations in Austria and Germany in collaboration with the German Aerospace Center (DLR) and three more participating institutes: The ‘Institut für Weltraumforschung’, Austria, Technische Universität Berlin, Germany and the Max Planck Institute for Solar System Research, Germany.

A detailed list of all observation posts can be found on the map. After the observations are conducted, we will publish pictures provided by ESA’s observation teams. Stay tuned!


Note:

The International Meteor Organization welcomes your visual meteor observations. Visit their website (www.imo.net) for instructions. Come out of your office and do some science from a sleeping bag!

Source: ESA - News

I'd thought I'd share this piece of advice that was shown as a graphic on my local news for viewing the meteor shower along with other helpful information:

"Look up"

There was cloud cover over every inch of the sky!

I actually had a clear sky. Being on the outskirts of London the light pollution is such that only the brightest of the meteors is visible even when the Moon is new ( as it was last night). Never the less as I set my camera up I saw three real beauties. I wanted to finish the film in my camera and so I took 2 five minute exposures. During that 10 ten minute period I saw not a single Perseid. I'm hoping the camera caught some I didn't see.

I spent a while outside last night looking out for them, luckily the clouds cleared up just in time. Although they were quite frequent at first they weren't as impressive as the few I saw on Saturday night, probably because of increased light pollution.

Although I was surprised when I saw a meteor going the wrong way (heading east). Is it possible that it wasn't a Perseid, rather a sporadic meteor with remarkable timing? I can't think of how else to explain it.

One of the brightest meteors I have ever seen was a sporadic during the Perseids.

13 August 2007

This image of the Perseid meteor shower was obtained in the night between 12 and 13 August 2007, when this recurrent summer phenomenon reached its intensity peak. The image was taken by ESA’s SPOSH camera during a 30-minute time frame, with 2-second exposures.

Stars appear as describing arcs around the pole star. The pole star itself shows up as a point, as it is almost stationary during the exposure time. The meteors are visible as streaks crossing the path of the stars.

Credits: ESA

Enthusiastic observers were rewarded by a nice display of the Perseid meteor shower that was visible at its best in the night between 12 and 13 August 2007. We present glimpses of the spectacle and the scientific rewards of staying up all night.

The comet Swift-Tuttle orbits the Sun with a period of about 130 years. Whenever the comet comes close to the Sun in its orbit, it ejects a stream of dust particles, which are then distributed along its orbit. When the Earth passes through their path - a regular occurrence every August - we see a meteor shower, a fabulous spectacle for viewers on Earth. The last such ejection from Swift-Tuttle took place in 1992.

Due to the relative orientation of the orbits of Earth and the comet, the meteor shower appears to originate from the constellation Perseus. This is why it is called the ‘Perseid’ meteor shower. As dust particles enter the atmosphere, they interact with it and generate light before they disappear.

The Meteor Research Group of ESA performed coordinated observations at several locations in Austria and Germany in collaboration with the German Aerospace Center (DLR) and three other participating institutes - The ‘Institut für Weltraumforschung’, Austria, the Technische Universität Berlin, Germany, and the Max Planck Institute for Solar System Research, Germany.

The Smart Panoramic Optical Sensor Head (SPOSH) camera imaging the night sky between 12 and 13 August 2007 (when the Perseid metor shower reached its peak), at the Kanzelhöhe Observatory in Austria.

The (SPOSH) camera, a highly sensitive instrument whose performance was tested during the Perseid observation campaign, is built for future use as a night-side imager of planets. It could also be used to observe meteors from space.

SPOSH was developed by Jena-Optronics and DLR under ESA contract.

Credits: ESA

The campaign had three main goals: to determine the orbits that the particles followed before they encountered the Earth, to study the physical properties of the dust by recording the light they emit (or their light-curve), and to test the performance of a new camera, known as the Smart Panoramic Optical Sensor Head (SPOSH).

The SPOSH camera, a highly sensitive instrument, is built for future use as a night-side imager of planets. It could also be used to observe meteors from space.

The test during the Perseid shower showed that the camera, which can image almost the complete sky, performed flawlessly. The top image, obtained with SPOSH during a 30-minute time frame with 2-second exposures, shows that stars appear to describe arcs around the pole star. The pole star itself shows up as a point, as it hardly moves during the exposure time. Meteors are visible as streaks crossing the path of the stars.

One of the cameras used by the ESA team was equipped with an objective grating, which splits up the meteor light into spectral colours. This allows the determination of the chemical composition of the particle.

About 30 meteors were recorded with this camera over about four hours. By combining this spectroscopic data with orbital data, it is possible to deduce the chemistry of the parent comet. This is done using models which describe how the dust particles lose some chemical elements with age.

With pairs of teams located from Northern Germany to Austria it was possible to use triangulation techniques to trace the individual trajectories of dust particles once they entered Earth’s atmosphere and the orbits of the meteors around the Sun (before they entered the atmosphere).

The orbits of the individual dust particles are similar to that of the parent comet Swift-Tuttle; however, they do not match exactly. Differences are introduced due to gravitational effects from planets and the influence of the Sun. Understanding these differences will shed light on the evolution of the dust particles in the Solar System, and on the ejection process of the particles at the comet.

The next scientifically interesting meteor display coming up is the Aurigid shower, a once-in-a-lifetime show originating from a long-period comet taking about 2000 years for each of its orbits around the Sun. The meteors from this comet reach us only every 70 years. It is expected to be visible from North America, Mexico, and Hawaii, with its peak on the morning of 3 September 2007.


Note:

The SPOSH camera was developed by Jena-Optronics and DLR under ESA contract.

Source: ESA - ATV

Cloudy and raining at my location...Rats!