AMATEUR ASTRONOMY:
JOVIAN SHADOWS:

Coming up in our night sky this weekend which, miraculously enough, is predicted to have clear nights skies.... With only a small low power telescope you'll be able to witness a rather unique event as all four of the Galilean moons of the planet Jupiter casts shadows that will be visible on the planet's surface. Jupiter can be easily spotted in the next few nights as it rises in the southeast and gradually makes its transit across the sky to the southwest as dawn approaches. It is quite bright ( -2.7 magnitude), and is in the constellation of Aquarius near to Pisces.

Tonight is also the peak night of the Taurid meteor shower, in Taurus of course. While not as spectacular as the Leonid meteor shower due to arrive later this month it has the advantage at least in Winnipeg of having good viewing conditions and relatively clement weather conditions.

Here's more on the upcoming "shadow transits" from the Space.com site.
JMJMJMJMJMJM
Jupiter's Moons to Perform Weekend Show for Skywatchers
By Geoff Gaherty

This weekend, a remarkable series of events will take place on Jupiter: The planet's four big moons will cast shadows on the gas giant planet that can be seen from Earth using a small telescope.

The planetary shadow play, which begins Saturday night (Nov. 6) and runs through early Sunday, will be primarily visible from the western coast of the United States. [Illustration: Moon shadows on Jupiter]

The four bright moons of Jupiter are known as the Galilean moons after their discoverer Galileo Galilei. As they revolve around Jupiter, they sometimes pass across the face of the planet as seen from Earth, as well as behind the planet and in its shadow.

How to see Jupiter's moon shadows

First, a word of caution: The overnight between Saturday and Sunday is when we switch back from daylight saving time to standard time, so be careful you get the correct time for your location.

Because the complete sequence of events is only observable from the U.S. West Coast, we will use Pacific Time here to discuss the best viewing times. Observers further east will miss the later events, and should add the appropriate number of hours to the times depending on their location and time zone.

The show begins at 8:53 p.m. PDT (11:53 p.m. EDT) on Saturday (Nov. 6), when Jupiter's largest moon Ganymede begins to cross the planet's face.

Because Ganymede has a relatively dark surface, it appears bright against the limb of Jupiter — but quickly appears to change to a dark gray against the bright central parts of Jupiter's disk. This can be seen with telescopes that have as small as a 5-inch aperture.

At 9:47 p.m. PDT, a second moon — Europa — follows Ganymede across Jupiter's face.

Because Europa's surface is icy, it reflects a much more light than Ganymede, and closely matches Jupiter's cloud belts behind it. As a result, it vanishes in all but the largest telescopes, perfectly camouflaged.

At 10:24 p.m. PDT, yet another moon — the volcanic Io — begins to disappear behind the opposite side of Jupiter.

At 11:52 p.m. PDT, Europa's shadow starts to take a notch out of the western limb of Jupiter. This can be seen with telescopes that have as small as a 3-inch aperture. Two minutes later, Ganymede moves off the disk of Jupiter and is once again a bright spot in the sky.

But wait, there's more — the Jupiter moon show isn't over just yet. Here's a rundown of the movements of Jupiter's moons to watch for on Sunday:

At 12:31 a.m. PDT, Europa leaves the disk of Jupiter.
At 1:12 a.m. PDT, a second shadow, that of Europa, puts the bite on the west limb of Jupiter. We now have two shadows creeping across the face of Jupiter, while the moons casting them are off to the right, a wonderfully three-dimensional effect.
At 1:41 a.m. PDT, Io emerges from Jupiter's shadow, ending its eclipse.
At 2:00 a.m. PDT, Daylight saving time officially comes to an end, and you should move your clock back to 1 a.m.
Now, at 1:34 a.m., Pacific Standard Time, Europa's shadow moves off Jupiter's disk. Finally, at 3:08 a.m. PST, Ganymede's shadow also moves off the disk.
You may be puzzled by the fact that Ganymede leads Europa across Jupiter's disk, but Europa's shadow precedes Ganymede's all the way across.

That's because Europa orbits much closer to Jupiter than Ganymede, so that the angular distance between Ganymede and its shadow is much greater than the angular distance between Europa and its shadow.

Gallery: Photos of Jupiter and its Moons

The Non-Event of the Leonids:
As I said previously, I was outside to try and view the Leonid meteor shower. To say the least it was a disappointment. I saw about 3 meteors until the cold set in. This was sort of expected as the peak viewing places were predicted to be in Europe and the East Coast of NA. Even there, however, the display was disappointing, as many people have remarked on the internet. Yet there is still hope for this year. The Geminid meteor shower is due on the evening of Dec 13/14. This year there will be only slight interference from a waning crescent moon. More on this later on this blog. Also more on the upcoming winter solstice.

Leonid Meteor Shower This Saturday:
The annual Leonid meteor shower will arrive this Saturday and will peak at 11:45 EST. This will be most visible in Western Europe and the Eastern seaboard of North America. in Western Europe the peak will be expected at 4:45 GMT. At this time Leo will be high in the southeastern sky just before sunrise. People here in Winnipeg and other areas of central North America will be disappointed as the peak viewing hours will be in or around dawn when Leo rises on the horizon.
The Leonids put on a spectacular display in 1966, despite the pessimistic predictions of many astronomers. One fireball from the display was 30 times brighter than the planet Venus, and the "meteor shower" became so intense in many places that it was impossible to keep accurate counts. more than 30 per minute were recorded in Arizona.
The Leonids are the "remains" of comet Temple-Tuttle, and they occur each year in mid-November. It's expected that many of the meteors will be visible even from urban locations. Space.com has provided a detailed guide to this celestial event.
Meteors are mostly the remains of passing comets or asteroids. When they pass through the Earth's atmosphere they are heated to over 3,000 degrees Fahrenheit. They are not actually heated by "friction" but rather by "ram pressure". When they enter the atmosphere they compress the air in front of them. The air heats up and, in turn, heats the meteor following behind it. Most meteors are vaporized by this heat. Some of them break up producing a fireworks-like display called a "fireball" and an explosion which can often be heard up to 30 miles away. Meteors which reach the ground are called "meteorites". A "meteoroid" is an object in space that may become a meteor if it hits the atmosphere.
How a meteor behaves depends on both its composition and the "angle of incidence" . Meteors falling at an oblique angle experience more stress, ad iron composition meteors withstand this stress better than "stony" or "cometary" meteors. Even iron based meteors will usually break up at an height of 7 to 5 miles up. If a meteor actually hits the ground it generally blasts out a crater 12 to 20 times its size. Larger meteors create not just a normal crater but also a "rebound effect" that creates a central peak.
Historical accounts of meteorites include an event in Connecticut in 1807 when several meteorites touched ground and, of course, the 1908 event in Tunguska, Siberia where many hundreds of square miles of forest were flattened by an exploding impact. The largest meteorite found in the USA weighed in at 2,360 pounds, and it was found in Nebraska in 1948. Big Boom to say the least. Meteor Crater in Arizona is one of the most famous sites of a meteor impact. The crater is 600 feet deep and about a mile wide. Evidence that the end of the Cretaceous age coincided with a massive impact off the coast of the Yucatan Peninsula has become pretty well standard theory in the last few decades. Throw a big enough smoke bomb and see what happens.
The best time to watch a meteor shower is usually in the early hours before dawn when the "leading edge" of our planet's rotation tends to catch oncoming meteors left by comets. yet this fact has to be put in place with the light conditions of viewing. Hence the poor viewing conditions where I live, in the central part of North America. The weather report, by the way, predicts clear skies for the night of the 18th/19th,;so you can bet I'll be out there in early dawn. Many flares of activity may also be seen tonight and Sunday.
Keep watching the sky;
Molly