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[Chicago Astronomer - Astro Joe]

Perseids Meteor Shower
- August 2005 -

The source of the shower is Comet Swift-Tuttle. Although the comet is nowhere near Earth, the comet's wide tail does intersect Earth's orbit. We glide through it every year in July and August. Tiny bits of comet dust hit Earth's atmosphere traveling 132,000 mph. At that speed, even a tiny smidgen of dust makes a vivid streak of light--a meteor--when it disintegrates. The shower is most intense when Earth is in the dustiest part of the tail.

Perseid meteors fly out of the constellation Perseus, hence their name. The best time to watch is during the hours before sunrise when Perseus is high in the sky: sky map. Between 2 a.m. and dawn on August 12th, if you get away from city lights, you could see hundreds of meteors.
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It's remarkable that many brighter meteors can still be seen through the light polluted skie of Chicago. I recall watching a good Leonid show from the NW side of Chicago two years ago with very good results... ;D

The Chicago Astronomers are planning to see this cool event together...and details are working on this right now!

[Chicago Astronomer - Astro Joe]

The Tears of Saint Lawrence

I share this interesting angle from Ireland on the Perseids...

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SWIFT METEORS

At various times throughout August, there are at least seven active meteor showers with some overlap, two for Southern Hemisphere observers and five for northern observers.

Probably the best of these showers for northern observers is the Perseid shower (see picture) whose broad peak this year is expected to occur during the early hours of August 12 and 13. Usually, up to about 80 fast-moving meteors, many with persistent trains, may be seen under ideal circumstances from suitable dark observing sites.

This year there will be no interference from the first quarter Moon as it will have set before the optimum viewing hours.

Every year the Earth encounters a stream of particles emitted by periodic comet 109/P Swift-Tuttle. This comet makes one complete orbit of the Sun roughly every 130 years and, each time it comes closest to the Sun, it sheds a fresh batch of particles.

The Earth encounters these mostly tiny particles at very high speed (over 130,000 mph) and, in the great heat generated, vaporises them in the upper atmosphere at heights of about 60 miles.

The shower is known as the Perseids because they appear to radiate from the constellation of Perseus. Some of the particles may be as large as pebbles, and these may cause bright fireballs.

The Perseids are also known from a German tradition as the 'Tears of St Lawrence' since the peak of activity of the shower occurs near the anniversary of his martyrdom in AD 258. This shower is probably the most famous of all meteor showers.

The earliest record of its activity appears in ancient Chinese writings in AD 36. The earliest sighting of Comet Swift-Tuttle appears to have been in the year 69BC and it was most recently at perihelion (closest point to the Sun) in 1992.

Edward C Herrick, a Yale University Librarian and Treasurer who had a persistent eyesight problem, independently discovered the annual Perseid meteor shower on 1837, August 9, and proceeded to make a life-long study of them. He tentatively suggested that meteor showers might originate from comets.

In the year of Herrick's death, 1862, Lewis Swift of New York, discovered a comet, eventually named 1862 O1, which later was found to be the source of the Perseids. Three days after Swift's discovery, Horace P Tuttle of Harvard College Observatory independently discovered the same comet, whence Comet Swift-Tuttle.

For the best views of these meteors choose a dark site with a clear, cloudless vista towards the north or east. After your eyes have become accustomed to the dark, look in this general direction at an altitude of about 45° keeping the radiant to the edge of your field of view.

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It's interesting to learn about various folklore on the same astronomical event.

[Chicago Astronomer - Astro Joe]

Here is something I ran across that is simple and clear regarding meteor showers from the Utah Skies Report:

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Perseids RA: 03:04 DEC: +58°

Annually there are more than 50 documented, separate meteor showers. Of these the Perseids are one of only three that have 100 or more meteors per hour (Zenith Hourly Rate) and is the only of the three that does not occur in winter. If you're going to try to catch a falling star, then this is the meteor shower to see.

The Perseids are so named because they appear to emanate from the constellation Perseus. In reality, the earth passes through the debris of a long-gone comet, which crossed between Earth and the stars that form the Perseus constellation. The peak activity level will be during the morning hours of August 12, although some Perseids can be seen during any dark hours between July 17 and August 24.

Meteoroids generally become visible when they strike the Earth's thermosphere, located at an altitude of about 50 to 75 miles (80-120 km). Once a meteoroid strikes the atmosphere and creates a brief flash, they are then called meteors. If a meteor (or pieces of it) manages to survive passing through the atmosphere and hits the ground, it is called a meteorite.

Meteoroids travel at an impressive speed, usually between 25,000 and 160,000 miles per hour. Since the Earth is moving 67,000 miles per hour around the Sun, meteoroids have to 'catch up' to the Earth to be seen in our evening skies, and as a result generally appear slower. In the morning, when the dark sky is the leading side of the planet, meteoroids appear to strike much harder and faster in the sky as they are hitting our planet 'head on.'

[Squirrel Mom]

I'm new to this board so if this has been asked before please forgive <damn newbies....>....

I live near Joliet and am looking for some advice on where I can drive to get un un-light polluted view of the sky for the Perseids and such stuff. Any advice? Anyone meeting out in the dark outside of Chicago that I could meet too? (Hey, now, I mean that in a nice way...)

Thanks in advance for any help.

[Chicago Astronomer - Astro Joe]

Hey SM,

Welcome to the Chicago Astronomer and for your first post.

All questions are welcomed and pleased to answer them.

We have many members here who live in the surrounding areas of Chicago who may offer some guidance in darker skies for the remainding days of the shower. I have a friend in the Kankakee area who enjoys dark skies, and Chicago Astronomer Bill likes the Silver Springs area for darker skies. Perhaps he will chime in.

How did you come across the Chicago Astronomer?

[Al Degutis]

Squirrel said:

I live near Joliet and am looking for some advice on where I can drive to get un un-light polluted view of the sky for the Perseids and such stuff. Any advice?

A couple of things to keep in mind...

• The Perseid shower just peaked on Friday (Aug 12th) so hourly rates will be dropping. By the end of this week the rate will be under 10 per hour.
  
• The best time to observe it is the last couple of hours before sunrise
  
• The darker the skies the better, especially as this shower winds down, so you're smart to look for a good dark site.
  

Good luck!

[Chicago Astronomer - Astro Joe]

Perseid Animation

This cool animation from Spaceweather.com comes from Portugal...

In Lisbon, Portugal, Filipe Alves photographed this brilliant Perseid fireball:

"This was the night's brightest Perseid," says Alves. "It exploded in mid-air, leaving behind a luminous cloud that was visible to the naked eye for several minutes."

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I like the trail it left behind.

I understand that the peak shower was not as good as expected. I didn't see a single one this year...

I often thought about just pointing my security camera up near the radiant and see what it can capture.

[Ruthann Cecela]

Hi. Please email me any information you have on upcoming meteor showers. We missed this one

Thanks

[e-mail]

[Chicago Astronomer - Astro Joe]

Ruthann,

Thanks for your visit to the Chicago Astronomer in seeking up-to-date astronomical information. The best way to keep abreast of the upcoming events is to return here on a regular basis, look around and post a question or two.

Thanks for your interest in the Chicago Astronomer.

[Al Degutis]

Ruthann said:

Hi. Please email me any information you have on upcoming meteor showers.

There are many minor showers that produce very few meteors going on throughout the year. The next major shower is the Orionids which will peak on Oct 21st.

You can get the complete list of showers here:
www.skyinsight.net/meteorshowerlist.php

or go to the main page:
www.skyinsight.net/
which shows the current and upcoming (next 30 days) of showers.