By Diane K. Fisher and Tony Phillips

CloudSat is one of the Earth observing satellites collecting data that will help develop and refine atmospheric circulation models and other types of weather and climate models. CloudSat's unique radar system reads the vertical structure of clouds, including liquid water and ice content, and how clouds affect the distribution of the Sun's energy in the atmosphere. To see animation of this data simulation, Click Here.

The story goes that a butterfly flapping its wings in Brazil can, over time, cause a tornado in Kansas. The “butterfly effect” is a common term to evoke the complexity of interdependent variables affecting weather around the globe. It alludes to the notion that small changes in initial conditions can cause wildly varying outcomes.

Now imagine millions of butterflies flapping their wings. And flies and crickets and birds. Now you understand why weather is so complex.

All kidding aside, insects are not in control. The real “butterfly effect” is driven by, for example, global winds and ocean currents, polar ice (melting and freezing), clouds and rain, and blowing desert dust. All these things interact with one another in bewilderingly complicated ways.

And then there's the human race. If a butterfly can cause a tornado, what can humans cause with their boundlessly reckless disturbances of initial conditions?

Understanding how it all fits together is a relatively new field called Earth system science. Earth system scientists work on building and fine–tuning mathematical models (computer programs) that describe the complex inter–relationships of Earth's carbon, water, energy, and trace gases as they are exchanged between the terrestrial biosphere and the atmosphere. Ultimately, they hope to understand Earth as an integrated system, and model changes in climate over the next 50–100 years. The better the models, the more accurate and detailed will be the image in the crystal ball.

NASA's Earth System Science program provides real–world data for these models via a swarm of Earth–observing satellites. The satellites, which go by names like Terra and Aqua, keep an eye on Earth's land, biosphere, atmosphere, clouds, ice, and oceans. The data they collect are crucial to the modeling efforts.

Some models aim to predict short–term effects — in other words, weather. They may become part of severe weather warning systems and actually save lives. Other models aim to predict long–term effects — or climate. But, long–term predictions are much more difficult and much less likely to be believed by the general population, since only time can actually prove or disprove their validity. After all, small errors become large errors as the model is left to run into the future. However, as the models are further validated with near– and longer–term data, and as different models converge on a common scenario, they become more and more trustworthy to show us the future while we can still do something about it — we hope.

For a listing and more information on each of NASA's (and their partners') Earth data–gathering missions, visit science.hq.nasa.gov/missions/earth.html. Kids can get an easy introduction to Earth system science and play Earthy word games at spaceplace.nasa.gov/en/kids/earth/wordfind.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

By Dr. Tony Phillips

In case it is ever found by intelligent beings elsewhere in the galaxy, Voyager carries a recording of images and sounds of Earth and its inhabitants. The diagrams on the cover of the recording symbolize Earth's location in the galaxy and how to play the record.

Tonight, when the sun sets and the twilight fades to black, go outside and look southwest. There's mighty Jupiter, gleaming brightly. It looks so nearby, yet Jupiter is 830 million km away. Light from the sun takes 43 minutes to reach the giant planet, and for Earth's fastest spaceship, New Horizons, it's a trip of 13 months.

That's nothing.

Not far to the left of Jupiter is Pluto. Oh, you won't be able to see it. Tiny Pluto is almost 5 billion km away. Sunlight takes more than 4 hours to get there, and New Horizons 9 years. From Pluto, the sun is merely the brightest star in a cold, jet-black sky.

That's nothing.

A smidgen to the right of Pluto, among the stars of the constellation Ophiuchus, is Voyager 1. Launched from Florida 29 years ago, the spacecraft is a staggering 15 billion km away. It has traveled beyond all the known planets, beyond the warmth of the sun, almost beyond the edge of the solar system itself…

Now that's something.

“On August 15, 2006, Voyager 1 reached the 100 AU mark—in other words, it is 100 times farther from the Sun than Earth,”” says Ed Stone, Voyager project scientist and the former director of NASA's Jet Propulsion Laboratory. “This is an important milestone in our exploration of the Solar System. No other spacecraft has gone so far.”

At 100 AU (astronomical units), Voyager 1 is in a strange realm called “the heliosheath.”

As Stone explains, our entire solar system—planets and all—sits inside a giant bubble of gas called the heliosphere. The sun is responsible; it blows the bubble by means of the solar wind. Voyager 1 has traveled all the way from the bubble's heart to its outer edge, a gassy membrane dividing the solar system from interstellar space. This “membrane” is the heliosheath.

Before Voyager 1 reached its present location, researchers had calculated what the heliosheath might be like. “Many of our predictions were wrong,” says Stone. In situ, Voyager 1 has encountered unexpected magnetic anomalies and a surprising increase in low-energy cosmic rays, among other things. It's all very strange—“and we're not even out of the Solar System yet.”

To report new developments, Voyager radios Earth almost every day. At the speed of light, the messages take 14 hours to arrive. Says Stone, “it's worth the wait.”

Keep up with the Voyager mission at voyager.jpl.nasa.gov. To learn the language of Voyager's messages, kids (of all ages) can check out spaceplace.nasa.gov/en/kids/vgr_fact1.shtml .

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

AOAS' own comet expert, Mike Holloway, has been following the latest visitor to the inner solar system known as Comet C/2006 P1 McNaught over the past several months. It is only rarely that we are treated to a comet which becomes a real spectacle as it makes its closest approach to the Sun, and Comet McNaught is certainly now a spectacle. The last comet that was this spectacular and sported several similar aspects to McNaught was Comet West in March 1976.

While we won't be able to see this comet's grand finale as it has now switched to the southern skies, there are plenty of experienced amateur astronomers in the southern hemisphere. Here are the images from Mike Holloway's newly restored Holloway Comet Observatory as McNaught came into prominence for the northern observers, and also the work of Australian astronomer Vello Tabur detailing this comet's unexpectedly exciting apparition for southern observers.

Mike Holloway imaged the bright comet C/2006 P1 McNaught near the horizon north of Van Buren on January 8, 2007. It had only recently been characterized as the brightest comet in 30 years.

It may only happen every 30 to 50 years. Either a new or a long-period (200+ years between apparitions) comet returns to the inner solar system and brightens to a level so bright that they can sometimes be seen even in broad daylight! New comet C/2006 P1 McNaught has become the first comet to reach this level of brightness in at least the past 30 years.

Our own AOAS comet photographer has been watching and imaging McNaught for the past few months, and occasionally sending me an email expressing his suspicions that this one would be especially bright. It was my own fault for not listening to Mike before the first of 2007, but I'm now a true believer.

On January 11, I was at the Git-R-Dun laundromat on Logtown Hill in Van buren, AR, when I started watching for the comet as the Sun set below the horizon that evening. Without any trouble at all, I could see it in considerably bright twilight, even the tail stretching up and curving to the right of the nucleus. I asked everyone in the laundry at the time to come and see, and all but two were also able to see it without optical aid. That's a fairly profound thing to someone like myself who has seen a number of comets in the last 22 years, but I've never seen one anywhere close to that bright ever before. My only disappointment was the knowledge that when the comet was to be at its brightest a few days later, it would by then be below the horizon for all northern hemisphere observers making that sighting my only view of the comet.

Australian astronomer Vello Tabur imaged comet McNaught on January 19th with an impressive tail sweeping away to the north of the comet's nucleus.

For northern hemisphere observers and comet chasers, the show from comet C/2006 P1 McNaught is over. Our luck just didn't pan out this time. It happened similarly for southern hemisphere observers for comets Hyakutake and Hale-Bopp in 1996 and 1997 respectively. Then it was we who had the show of a lifetime, while our southern counterparts only saw the later remnants of those two comets. All of us who were able to see those comets will never forget their appearance, just as southern astronomers will likely never forget this appearance of Comet McNaught.

Click read more for the BEST images and for links to images of other exceptionally bright comets in the (relatively) recent past.

"Science and the technical wonders it produces CAN blaze suddenly towards the heavens and then just as quickly return to the desert sands, lost and forgotten."

The Antikythera Device, a computer from ancient times recently determined to be an accurate mechanism for determining the movements of the Sun, Moon and five known planets of the ancient world. Source: Wikipedia, taken from APOD for December 5, 2006.

One of the quiet but great stories of 2006 was the confirmation that a lump of corroded metal retrieved more than a century ago from the Aegean Sea was in fact an extremely ingenious ancient computer revealing a computational sophistication unmatched until the fourteenth century. In an article in the November issue of Nature, a panel of scientists and classical scholars led by Michael Edmunds released their findings on the Antikythera Mechanism, named after its place of discovery in A.D. 1900 in a Roman shipwreck. Said Edmunds, "Before its sojourn on the sea bed, (the Antikythera Mechanism) computed and displayed the movement of the Sun, the Moon and possibly the planets around Earth, and predicted the dates of future eclipses. It’s one of the most stunning artifacts we have from classical antiquity."

The Mechanism, enclosed within a wooden case a little bit smaller than a shoebox, contains at least 30 gear wheels, each one handcut from a single sheet of bronze, and ranging in size from nearly the width of the case to less than a centimeter across. On the front and sides are a number of dials and windows showing the zodiac, the day of the year, the phases of the moon, and the positions of the sun, moon and five planets known at the time. On the back are two spiral dials--one showing the 235 month Metonic cycle, which correlates the orbit of the moon around the earth with the earth's orbit around the sun, and the other the 223 month Saros cycle, used to predict ecllipses.

We even have the names of who could have built this technological wonder. The wrecked ship that the Mechanism was on could be dated to sometime in the first century B.C. and probably from the Greek islands of Rhodes and Cos. On the device itself was a dial to compensate for errors in the Egyptian calendar which was used at that time. This dial was adjusted in such a way that researchers were able to determine an exact date - 80 B.C. - when the Mechanism was last set. Classical scholars also know that just seven years earlier, in 87 B.C., a Greek named Geminus wrote a book which describes a device that sounds remarkably like the Antikythera Mechanism.

Jay Hilgartner sits at a computer station in today's modern Library of Alexandria where he recently visited. The new library is built on the site of the ancient Library of Alexandria, where detailed plans for building a device such as "The Antikethera Mechanism" may have been kept. All photos by the author unless otherwise noted. Click HERE for interior of library, and HERE for exterior.

Perhaps it was built by Geminus himself or by another astronomer mentioned by him - Poseidonius of Rhodes. Poseidonius is also mentioned by Cicero as the designer of an instrument which records the movement of the Sun, Moon, and the five planets. Or, others say, it may have been designed centuries earlier by the brilliant Archimedes or by another Rhodes’ astronomer Hipparchus, who died around 120 B.C.

Suffice it to say that the sophistication of the Antikythera Mechanism gives all lovers of science and civilization pause, for it challenges the idea of continued uninterrupted human progress. Science and the technical wonders it produces CAN blaze suddenly towards the heavens and then just as quickly return to the desert sands, lost and forgotten. Indeed, the Hellenistic world that the Mechanism was created in did just that.

The great city of Alexandria in Egypt, the center of Hellenistic culture, once boasted a library and museum containing over half a million books, attracting scholars from all the known world. It was the first deliberately built great research center, museum, and library all in one, lavishly supported by the first three Ptolemy pharaohs. The library flourished for almost 300 years until it was burned in 48 B.C. during Julius Caesar’s war with Pompey. Many books were lost, but many also survived in a branch library in Alexandria at a temple complex called the Serapeum. With the Roman conquest, Alexandria’s golden age had passed but scholars still regarded the city as the place to complete their studies, that is, until the fourth century A.D. when the Serapeum was destroyed by an angry Christian mob. The books were either burned or lost in time. It is sobering to think that a scroll describing how to construct the Antikythera Mechanism may have been destroyed either in the library’s first fire or in the destruction of the Serapeum.

Click read more for the rest of this fascinating story.

I previously gave some recommendations for buying a telescope in another AOAS website story. Then it occurred to me that a telescope is only as useful as how well its owner can understand how it operates. Just, “…point it up that-a-way!” isn’t a very good idea, although I more-or-less started this way myself. My earliest beginnings would have been more enjoyable if I’d had some helpful suggestions and explanations.

STEP 1: Setup in daylight. Learn all the parts and functions of your telescope while you can see them clearly. In darkness, you'll be doing this all by touch alone.

I assume, although it may not necessarily be correct, that every telescope owner wants to use their telescope to see something in the sky. That is, after all, the most widely accepted use for telescopes. So, here are a few (hopefully) helpful suggestions on how to make that new telescope live up to some of the promises you expect from it.

Oh, and BTW - this is my third attempt to pen a story about “How to Use Your New Telescope”, honestly! I’d get started and the words would just flow and flow…….endlessly……about too many things that you don’t need to know so early in the game. I'll touch on these things in Pt 2. So here is my third attempt, this time with a set of blinders on, so that I can keep this version below 20,000 words, I hope.

You’ve bought a new telescope, and you’ve just finished putting the last item together and attaching it to the telescope tube. This will usually be the finderscope since that’s generally the last step in the instruction manual. But what is seldom made plain in the instruction manual is that the finderscope is the most important thing you should learn about. Here’s why…..

STEP 2: Locate a distant target.

All telescopes “see” a pretty small piece of sky. Almost every telescope’s widest possible field-of-view is only about the size of a quarter if you hold it out at arm’s length. That’s a pretty small field-of-view when you think about it, while the finderscope sees an area about the size of your clenched fist at arm's length. Now let’s abbreviate field-of-view to just FOV, and a big FOV is a popular misconception that most people have about what a telescope "sees". This may be one of your first realizations of many, many future new realizations concerning astronomy. Telescopes do NOT see large chunks of the sky!

FOV is different from one telescope to another, but by only a very small amount. What you must understand here is that a telescope’s finder sees a several-times-larger FOV than the main telescope, making it easier to get the telescope pointed in the right area. Learning how to properly setup a finder will assist you in finding almost any target you seek and usually on the very first try. We begin our setup in daytime, outside, with a target at least 500 feet away.

“See That Telephone Pole Down the Road?”

STEP 3: Center something you can see easily, like this insulator on top of that telephone pole.

First, a word about eyepieces. An eyepiece is what couples the light from an object to your eye, something similar to the way a speaker couples your favorite music to your ears. Great speakers can make a so-so receiver sound GREAT, and the same is true of good quality eyepieces for so-so telescopes. If your telescope came with low quality eyepieces, consider upgrading to quality eyepieces. It's a cheap way to dramatically improve your image quality in even the cheapest department store telescopes. Eyepieces can help a telescope see a wider FOV, and the eyepiece(s) that were supplied with your telescope are what you’ll start with. The lowest power, or more accurately the lowest magnification gives the widest FOV in your telescope. This is always the eyepiece with the highest number stamped on its side, maybe something like 25mm or 32mm.

Click read more for the rest of this finderscope alignment article.

Back in action after a lightning strike destroyed all his original equipment in August 2006, AOAS astrophotographer Mike Holloway has upgraded his equipment and is now imaging comets, nebulae and galaxies better than ever.

A new Losmandy G-11 mount, carrying the new TeleVue NP-127is refractor tube and the SBIG camera are the new replacement components of Mike Holloway's private observatory located about 12 miles NW of Van Buren, AR.

You could only imagine how it felt if it had happened to you. Mike Holloway had to deal with a balking insurance agent, an obstinate high-end CCD imager manufacturing company, a VERY long waiting period for a replacement of his primary telescope, and the sheer frustration of watching thousands of dollars worth of fine instrumentaion turned into extremely beautiful paperweights. But, now that he's returning to full operation in his private Holloway Comet Observatory, he's finally happy once again.

Happy can be a relative term sometimes, but Mike really is happy again. Part of the reason for that is in how he had to deal with all the ins-and-outs of buying new equipment that would replace the fried refractor, mount and imager which were destroyed by a direct lightning strike on August 4, 2006. Anyone would be happy if you had the same equipment that Mike now has to work with on a regular basis.

Take the new refractor, now a TeleVue NP-127is, a 5" f/5.2 refractor that replaced the ridiculously backordered Takashi FSQ 106ED, a 4" refractor. As Mike told me on a recent visit to his observatory to grab some imaging pointers, "This thing is SOOO much better than that 4", I just can't believe it. I'm much happier with this one."

His other mount was the Losmandy G-8, which, like everything else, was totally lost to the forces of Mother Nature.

Comet C/2006 M4 Swan in this 7-image mosaic taken October 29, 2006 by Mike Holloway. This was one of Mike's first comet images after getting some of his equipment replaced. The telescope is his new TeleVue NP-127is on a Losmandy G-11 mount with an SBIG ST2000 camera.

He now has upgraded that to the Losmandy G-11, and again he's much more happy with this new mount as opposed to the G-8. "It's sturdier, smoother, and handles this new tube assembly with ease," said Mike. He feels the extra cost of the G-11 was almost cheap in comparison to the increased load capacity and greater overall compatibility with his other new components.

And then there is that expensive CCD camera from Finger Lakes Instruments that was virtually blown to bits from the energy released in the lightning strike. You'd think that after selling him one camera, the company would at the very least be willing to sell him another new identical camera for the price of the first one. Somehow, though, they didn't see it that way and Mike settled on buying a new SBIG ST-10XMEI, one of the most sensitive and sophisticated imaging CCD's in the marketplace. Yep....Mike's a happy, happy guy!

Click read more to see some deep-sky objects with ALL of Mike's new equipment in FULL use.

One of the most asked questions that AOAS members, or any amateur astronomer faces is, "What kind of telescope should I buy?" This time of year we hear it more often. I'll try to give you some ideas about how you can help steer someone in the right direction the next time you hear this question.

Sometimes, asking questions can be most helpful in trying to assist someone in making a choice for a telescope. Ask them some basic questions about, 1) How much they want to spend? 2) What they want to see with a telescope? 3) Where will they use their telescope? And 4) Do they have any restrictions on how much they can lift or carry? These are among the most important questions that will help them make the right choice. Its all about which telescope they'll use most often. They won't be happy with any telescope that they don't, or can’t, use regularly.

Small refractor telescopes such as this is what to watch out for at the mega-department stores. In general, the optical glass that forms the image in these telescopes is of sufficient quality to give acceptable images, but the wobbly mounts and the inferior eyepieces supplied with these type of telescope is ALWAYS the thing that does them in. FOREGROUND: Franzie, 1997-2005;Coleman Chief of Security - 2003-2005

The "COST" of a Telescope

Some telescopes can cost a small fortune. These are NOT for the beginner. Many amateur astronomers prefer to influence a beginner to first learn the sky, and begin their star gazing adventures with a pair of binoculars. I have sometimes urged people to first attend several astronomy club star parties, where they can look at objects through club members telescopes and then decide if a telescope is right for them. That's also good advice, but assuming you're going to buy a telescope for yourself or someone special, here are my thoughts and advice for you.

A basic entry-level telescope will run from about $210 and as much as $500 dependent upon an individual’s budget. You shouldn't invest too much early on until you have some idea of whether you like the hobby of amateur astronomy enough to become more deeply involved. But remember.....to get the most out of whatever telescope you may buy, you'll want to start learning the sky anyway in order to locate the telescopic tidbits dwelling there.

These dollar amounts will give the buyer a choice of either a small refractor on a good mount, a small to medium-sized reflector on a simple-yet-sturdy Dobsonian mount (see my story about John Dobson under Topics: Telescopes), or a small reflector on an equatorial mount. Here’s where a little bit of “Telescopes 101” can come in handy.

Telescope Basics

Refractors, reflectors, Dobsonian mounts, equatorial mounts, and when you really think about it, just what exactly is a small or medium-sized telescope, anyway? Well, whether it’s a refractor or a reflector, the main optical component for all telescopes is called the “objective”, and the objective can be either a lens, if a refractor, or a mirror if a reflector. There is also a type of telescope which utilizes both lenses AND mirrors, and these are called catadioptrics, or compound telescopes. [See an image of one by clicking "read more" below]

A home-made 80mm f/13 refractor. AOAS member Margaret Brogley asked me to help her restore this telescope built by her brother in the mid-1950's. I built the wooden mount which gave it the stability it needed to work well. Wobbly mounts are a frequent problem found in smaller refractor telescopes.

A small refractor is in the 70mm to 90mm range, or for the metrically challenged, a 2.7” to 3.5” diameter of the main lens. For a reflector, a small size is typically a 4.5” or a 6”, while an 8”mirror can be considered by some to be medium-sized.

Size Really Matters!

Never be lured into a situation of buying a refractor telescope at a department store. I tell everyone the same thing, “NEVER buy a telescope based on the “Mag Factor” ….magnification is NOT what gives good images. The size of the objective and its quality of craftsmanship are what really count the most. A Wally-World Rosco telescope advertising 650x power isn’t even worth a second glance, except maybe as an example of what you don’t want to buy.

Telescopic Targets

There are close objects within our solar system, the moon, planets, comets and asteroids, all of which refractors work very well on, and then there are the galaxies, nebulae, and thousands more objects in the deep-sky available for viewing with 4.5” to 8” (and larger) telescopes.

Click read more for more targets, more helpful suggestions about choosing telescopes, and for a group of links to some telescope manufacturers and dealers.

The usually productive Geminid meteor shower reaches its peak each year on the evening of December 13 & 14. In 2006 this is the middle of the week. Geminid meteors are occasionally bright, relatively slow compared to other showers during the autumn months, and best of all, they will restore your faith in meteor showers, at least, as long as the clouds stay away!

UPDATE: 12/14/06 The Geminids did NOT disappoint this year! AOAS members in attendance at Coleman Observatory were treated to rates of at least 90/hr, and the rates could have been as high as 110/hr. Along with the pleasantly warm temperatures, an exceptionally clear and steady sky, and lots of viewing the universe with our 14" computerized telescope, we all enjoyed ourselves, some until nearly 2:30am. We won't likely see another meteor shower this good again for a while, so if you missed this one, you missed a really good one!

Look to the ENE horizon at about 8:00pm on Wednesday, December 13, 2006. Orion will be to the SE of Gemini, and about as high above the horizon. Kick back in a lounge chair or in a thick, warm sleeping bag and just stare at as large of an area of sky as you can take in. Expect to see 50 meteors every hour originating out of the area near Castor early on. Rates will increase to 70/hr and may occasionally reach 90/hr as Gemini rises to near the zenith around 1:00am on Dec 14.

November 12, 1833 was just another day, but that night brought the end of the world! On that evening the greatest meteor STORM in human history occurred with an estimated fall-rate of up to 300,000 PER HOUR! Every place that witnessed the spectacle saw people fearing that the end of the world was at hand. This gigantic event was witnessed from Europe across the North Atlantic and well into the middle of North America, and it is said to be solely responsible for the birth of modern meteor science.

The 1833 outburst of activity was from the Leonid meteor shower. The Leonids fall from an area in the "head" of the constellation Leo every November 17-18. Even the east coast of the US saw rates of fall in 1833 on the order of a few thousand per hour, and needless to say, most people who witnessed that event would never be the same again. Many were convinced that what they were seeing was a direct effect from the Hand of God.

At the time, science had only recently begun to accept the notion that meteorites were pieces of rock and metal that fell to Earth from outer space. It simply seemed too counter-intuitive to be true, at least as far as most people were concerned, and there were some influential individuals in that group. One such person, a scientist who was also our second president of the United States, Thomas Jefferson, supposedly remarked after a recent fall of a small stone meteorite in Connecticut, "I'd [sooner] believe that two Yankee professors would lie than [accept] that stones would fall from heaven."

One of three images I took of the Leonid meteor shower of November 18, 1998, the night of 100 fireballs! This one ended in a "terminal burst" which is when a meteor briefly fades away and then suddenly bursts into light as it is completely consumed by the frictional heating with air molecules. Can you see the faint red horizontal streak of color near the trees? That's a "train" of still glowing air molecules left over from another recent bright fireball only minutes before I took this image.

This statement is believed to simply be folklore, but it reflects the feelings of the majority of laypeople and even most scientists of the day. Sometime around that same period in history, the connection between meteors and comets was also established. Those who studied the orbital motions of comets recognized that the thousands of meteors which fell in 1833's Leonid storm bore a remarkably close resemblance to the orbittal path of comet Temple-Tuttle. And, it just so happened that the comet was making its normal 33-year periodic visit to the inner solar system at around the same time. The Leonids sometimes produce HUGE meteor storms about every 33 years when Temple-Tuttle returns. Suddenly, here was the connection between meteors and comets right in the face of all who understood orbital mechanics based on mathematical formulae. Now we knew...annual meteor showers originated with the passages of comets through the inner solar system.

Meteors from ALL showers are simply that dusty material shed from their cometary parent-bodies as they pass through the inner solar system.

Earth's orbit takes us once around the Sun each year. If a comet has passed through the area where our orbit lies, we pass through dust particles left behind from that comet. We pass through the dust trails of several past comets every year.

I apologize for my drawing above, but without it I'd be forced to try and help you envision where the Geminid meteor shower comes from with mere words.

COMETS 101

A basic understanding of comets is needed here, and we must start with the elemental make-up of the comet itself. Comets are chunks of frozen water-ice and a wide mix of frozen gasses, as well as millions of tons of small pieces of dust and metal fragments. A typical comet is usually about the size of a large city, but some are thought to be up to many dozen miles in diameter. The general description of comets being huge "dirty snowballs" is absolutely accurate, and yet they are some of the smaller members of our solar system. Their apparent size is covered in the "read more" area.

Sometimes comets are set in motion from their origination point 10-billion miles away, towards the general direction of our Sun by a passing star or a gravity wave. Once this occurs, nothing can stop it, and the (frequently) odd-shaped comet nucleus will begin to form a dusty and gaseous halo around itself as the volatile frozen gasses are heated by the Sun's energy as the comet draws nearer. The Sun's solar wind is always blowing outward in all directions, and this energy causes the dust and gas to be swept backward away from the comet's head causing the characteristic "head-and-tail" appearance. No matter which direction the comet is moving, the energy from the solar wind ALWAYS forces the tail to point away from the Sun. A comet's tail points away from the Sun when the comet is inbound, and then the head actually follows the tail after it rounds the Sun and once again moves outbound through the middle-to-outer solar system.

Click read more for the rest of this story.

NEVER use a telescope to view the Sun, unless you use PROPER, SAFE solar filters. Instant and permanent eye damage may result! Proper filters cover the opening end of a telescope and must be rated as allowing a maximum of only .001 of 1% of visible light transmission. If you own a small telescope that utilizes a small screw-on filter that attaches to the eyepiece, THROW IT AWAY! These eyepiece filters can break from the intense heat of the Sun and you can not move fast enough to keep from being blinded PERMANENTLY!

Mercury is the innermost planet of our solar system. Being so close to the Sun it automatically has a very rapid orbital period. This gives Mercury a "year" of only about 88 Earth-days. On occasional orbits around the Sun, Mercury happens to pass in front of the Sun's face as seen from Earth, and when this happens, its called a transit.

AOAS will not be offering public views of the November 8 transit. But for anyone who wants to see this event, we have some web addresses where visitors can view the transit from many different telescopes located in some far-flung places around our planet.
UPDATE: I have posted two of my images of the transit. The one below lists the equipment used. The second is available by clicking on READ MORE below.

This image of the Venus transit from June 8, 2004 was taken with my digital camera as it appeared on my monitor while watching the event "live" via webcast from two different solar observatories in the eastern hemisphere. Click "Read More" below to go to the web addresses for live views of this next transit on Nov 8. Click here to see my album of images of the Venus transit of June 8, 2004.

AOAS members at our October 6th meeting discussed the possibility of hosting the public to view this semi-rare event of Mercury transiting the face, or disk, of the Sun. When we considered the day of the week, the absolute necessity of having a solar filter for magnified views of the tiny disk of Mercury, and the "oomph", if you will, the amount of bang for the buck invested, we decided NOT to setup our telescopes for this event.

Mercury transits the Sun on average about 13 or 14 times each century. I watched the November 1999 Mercury transit from my home in Sallisaw with my dad. His eyes didn't allow him to see the tiny (and I mean, TINY) pitch-black disk of the planet near the edge of the solar limb, but I could see it without too much trouble. But as I watched the event over a short period of time, I had to wonder what all the hooplah was about for planetary transit in the first place. I mean, when it comes right down to it, you need a telescope with a proper and SAFE filter for viewing the Sun, and lots of patience to watch the event as it slowly drifts across the disk.

Here is one of my first images of Mercury just after it had begun its transit. Notice the nice sunspot near the limb. This image is taken with a Meade ETX125-EC w/o drives, and withmy home made solar filter with Baader Astro Solar Safety Film. I used a 26mm Plossl eyepiece. The camera is my Canon PowerShot A10 at nearly full zoom (about 4.5X ?) and on automatic.

In 1999, the event was a very "shallow" transit, meaning it entered and crossed near the edge of the Sun's disk giving a length of time of only an hour or so from start to finish.

This transit on Wednesday, November 8, 2006 will be a much "deeper" transit across the Sun's disk, and the event will last 5 hours, from around 1:12PM when it first touches the Sun until just after the Sun sets in the west as seen from Van Buren. Folks need to be west of a line running north-and-south through the Rocky Mountains in order to be better placed to allow viewing of the entire transit. Hawaii and Australia are best placed for this particular transit.

But, knowing that there will likely be people wanting to see this event, we offer this link to the Exploratorium for a live feed of the transit as it progresses from observatories around the world such as Kitt Peak in Arizona , or possibly Keck or any of the other of the myriad observatories located in Hawaii. This will assure everyone interested that you'll be able to see a live streaming video of the entire transit, all 5 hours of it, without interuption from clouds or other disturbances.

Visitors to the Exploratorium will also find detailed explanations as to what a transit is, and how to view it safely. There is much information on past transits and future transits as well.

So, visit AOAS when we have one of our frequent nighttime viewing events. We'll gladly show you dozens or even scores of dim deep-sky and planetary objects. But for the November 8, 2006 transit of the Sun by Mercury, go to the Exploratorium, or perhaps another site to watch this event take place in complete comfort and safety, and enjoy a ton of other information about what's going on, too.

Click read more for another image after nearly an hour into the transit.

NASA's Cassini spacecraft in orbit around Saturn since January of 2005 has taken yet another dramatically important image of the Ring World. Who could have forseen this wonderful image taken as Cassini moved through the shadows of the Saturnian night looking back at both the Sun, and our own Earth!

Its a sort of over-the-shoulder image taken by Cassini's camera's as the spacecraft sped through the darkness of Saturn's night side and looked back beyond Saturn towards the Sun. The outermost diffuse "E" ring is the newly discovered ring created by water ice spewing from the ice-fountains of Saturn's moon Enceladus.

Saturn's beauty is seen anew at almost every orbit around the Gas Giant turned in by the robotic Cassini spacecraft. Giovanni Cassini was the first to discover a gap in the Rings of Saturn with a telescope dividing them into the wider inner ring and the narrower outer ring. This gap is named the "Cassini Division" in honor of him. How fitting that the spacecraft that bares his name should have discovered the newest "ring" of the system created by the orbiting moon Enceladus as its water-ice fountains spew their material into space along its orbit.

This image comes from the Astronomy Picture of the Day (APOD) for October 16, 2006. CLICK HERE to see the image in larger and finer detail. By doing so, you'll also see a small dot just above the bright rings and slightly inside the narrowest sharp ring. It can easily be mistaken as one of Saturn's 35+ moons, but in reality, that's you, on Earth, that Cassini is looking back towards!

For continuously changing updates on the Cassini mission to Saturn, go to the Cassini Home Page and consider making it one of your "Favorites" or mark it with a "Bookmark", depending on your browser's home page. Check it once or twice a week to see all the newest images and science discoveries at Saturn's distance of roughly 750,000,000 miles from home.

Or you might want to review all of our AOAS website stories about Saturn and the Cassini/Huygens mission to the Ring World by clicking on the "Lunar and Planetary" section. This allows visitors to pull up our entire listing of stories about Mars, Saturn, Jupiter, as well as any recent comets and/or stories about asteroids.

It's still two more years before Cassini's original mission comes to its end, yet due to the spacecraft yielding SO MUCH data over the 4-year life span of the mission, we will likely see another 2, or maybe even another 4 years added on to the mission. One thing is almost certain, someday we will have another return trip to Saturn with an even more "magically" sophisticated and wonderous spacecraft giving us even more info on this beautiful planet. What new wonders will await us then?