A GLANCE INSIDE
What’s Up in November
NPMAS Election Results
A Look Back at October
Leonids in the Crystal Ball
On the Horizon
WHAT'S UP IN NOVEMBER
November 10th MONTHLY MEETING
Please join us at the Neville Public Museum from 7:00 to 9:00 PM. This month's topic will be "The Sun" given by club member Tom Jorgenson. Happy Joe's to follow!
November 15th TRANSIT OF MERCURY
The transit or passage of a planet across the disk of the Sun is a relatively rare event. On average, there are only 13 transits of Mercury each century. The last one of this century will be visible just before sunset on November 15th.
First contact should be about 3:15 PM local time with greatest distance into the Sun at 3:40 PM. The transit will be over by 4:07 PM, which is just before Sunset(4:25 PM). Look for Mercury on the Sun’s Northeastern limb.
November 16th - 18th LEONID METEORS
Most experts agree that 1999 is a likely year for a Leonids meteor storm. The estimated peak will take place between 7:00 – 10:00 PM local time on the 17th, making the morning of the 18th the best viewing (see Leonids in the Crystal Ball below).
Club member Steve Mofle is inviting other club members out to his house (2431 North New Franken Road) in New Franken to observe the shower/storm the nights of the 16th and 17th. Give him a call at 920-866-3523 for directions or to confirm.
NPMAS BOARD OF DIRECTORS ELECTION RESULTS
By Katrina DeWitt
This year was a record number of members running for nine slots on the NPMAS Board of Directors. At the October meeting, members had a chance to vote for which nine members who would oversee the club for the next two years.
Before I announce the results, I'd like to thank everyone who ran for the Board this year. It was great to see a lot of members wanting to be involved. I hope to have this kind of turnout for elections in 2001! I need to make a special thank you to Don DeWitt and Steve Mofle. Both of them had decided to step out of the running after serving several consecutive terms. They had told me they wanted to see new faces on the Board and more importantly, they both wanted to get out and do more observing. It was fun working with them and I wish them success in their hunt for Herschel 2's!
Without further ado, those elected (in alphabetical order) are as follows:
Tony Kroes and Jill Last are the two new individuals who join the Board for the first time! Hopefully, they will have some great input in the next couple of years.
While we ran out of time at the monthly meeting, the newly elected Board met on the last Wednesday of October to elect the officers as well as conduct their first official business. The new officers are as follows:
After coercing members to fill these important spots, they got down to business and made out the preliminary schedule of club events for 2000. Not a bad start for the new term.
A LOOK BACK ATOCTOBER
MONTHLY MEETING – October 13th
Over fifty people were in attendance for October's meeting at the Neville Public Museum. The great number was due to the presence of several members of the Packerland Chapter of the American Meteorological Society. This joint meeting featured a wonderful Power Point presentation of "Optical Phenomena" by Jeff Last.
Jeff gave detailed explanations of halos, glories, rainbows, sun dogs and other types of light reflections. Beautiful slides accompanied each subject. Excellent job, Jeff!
The talk was followed by election results which you can read about in more detail on page 1. The second hour featured club business and a slide show by Tony Kroes. Tony put together a sequence of several CCD images of a comet to show it’s motion in relation to the background stars. It was quite interesting and well done, especially considering it was a "first try". Nicely done, Tony!
BOARD MEETING – October 27th
Special meetings are held by the NPMAS Board of Directors several times each year. All interested club members are invited to attend these meetings to discuss club business and upcoming events. Future board meetings will be announced in "The Eyepiece".
Attendees were: Wayne Kuhn, Jill Last, Katrina DeWitt, Don DeWitt, Tony Kroes, Ron Parmentier, Gary Baier, Steve Wicker, Sue Wicker, Ray Nancoz, and Tom Cashman. Here are the meeting highlights:
LEONIDS IN THE CRYSTAL BALL
From Space Science News – NASA
Imagine tuning in to the local TV weather report and hearing this from the weatherman:
"Good evening space weather lovers! Last night Earth was hit by a high-pressure solar wind stream. It's expected to persist for 3 or 4 more days producing a 50% chance of mid-latitude aurora. But the big news today is the 1999 Leonid meteor shower. Experts are predicting a big storm on November 18th with up to 100,000 shooting stars per hour. Of course, we could be off by a couple of years. The storm might hit in 2001 instead. Or maybe not at all! Hey, if predicting these things were easy we wouldn't need experts!"
One day, space weather forecasts like this could be commonplace. As our society comes to rely on satellites, cell phones, and other space-age gadgets, forecasting solar storms and meteor showers can be just as important as knowing the chances of rain tomorrow. Three weeks from now we may be treated to a very visible reminder of space weather when the Leonid meteor shower strikes on November 18, 1999.
What's the probability of significant meteoroid precipitation? That's what stargazers and satellite operators everywhere would love to know.
Most experts would agree that predicting the Leonids can be tricky. To understand why it's helpful to know the difference between a "meteor shower" and a "meteor storm." Simply put, meteor showers are small and meteor storms are big. Meteor showers produce a few to a few hundred shooting stars per hour. Meteor storms produce a few thousand to a few hundred thousand meteors per hour. A meteor storm, like a total solar eclipse, ranks as one of Nature's rarest and most beautiful wonders.
A Leonid meteor shower happens every year around November 17 when Earth passes close to the orbit of comet Tempel-Tuttle. Usually not much happens. The Earth plows through a diffuse cloud of old comet dust that shares Tempel-Tuttle's orbit, and the debris burns up harmlessly in Earth's atmosphere. A typical Leonid meteor shower consists of a meager 10 to 20 shooting stars per hour.
Every 33 years something special happens. Comet Tempel-Tuttle swings through the inner solar system and brings a dense cloud of debris with it. For 3 or 4 years after its passage the Leonids can be very active. In 1966 for instance, over 100,000 meteors per hour were seen from parts of North America. Curiously, there isn't a full-fledged storm every time Tempel-Tuttle passes by. Sometimes there's simply a stronger-than-average shower. Sometimes nothing happens at all!
The period of maximum activity during the 1998 Leonid shower took place about 12 hours before the earth crossed Tempel-Tuttle's orbital plane. The early activity caught many observers by surprise, but it was business as usual for the unpredictable Leonids. Rainer Arlt of the International Meteor Organization noted that while the maximum activity came early, there was a secondary maximum when the Earth passed the comet's orbit (see left). This pattern is similar to that observed in 1965, the year that preceded the great Leonids storm of 1966. In his report, Bulletin 13 of the International Leonid Watch: The 1998 Leonid Meteor Shower, Arlt wrote: The radar, visual, and photographic records of the 1965 Leonids indicate an activity profile which resembles that of the 1998 Leonids. Even the low population index seems comparable. Judging from these phenomenological facts, we may expect 1999 to show a similar shape of activity as in 1966. The actual maximum meteor numbers are hardly predictable.
If the 1999 Leonids are anything like the 1966 storm, stargazers are definitely in for a treat. The 1966 event was, predictably, somewhat unexpected. The comet had passed by Earth's orbit in 1965, so astronomers were aware that something might happen. But, judging by the paucity of the 1899 and 1932 showers, it was widely thought that the orbit of the debris stream had been deflected so much by gravitational encounters with other planets (mainly Jupiter) that a close encounter with Earth's orbit was no longer possible. The best predictions suggested a strong shower over Western Europe with 100 or so meteors per hour.
Instead, there was an stunning display of shooting stars over western North America. This recollection by James Young at JPL's Table Mountain Observatory in California gives a sense of what the storm was like:
"This very noteworthy [1966] meteor shower was nearly missed altogether... There were 2-5 meteors seen every second as we scrambled to set up the only two cameras we had, as no real preparations had been made for any observations or photography. The shower was expected to occur over the European continent.
The shower peaked around 4 a.m., with some 50 meteors falling per second. We all felt like we needed to put on 'hard hats'! The sky was absolutely full of meteors...a sight never imagined ... and never seen since! To further understand the sheer intensity of this event, we blinked our eyes open for the same time we normally blink them closed, and saw the entire sky full of streaks ... everywhere!"
The 1966 return of the Leonids was one of the greatest displays in history, with a maximum rate of 2400 meteors per minute or 144,000 per hour.
Joe Rao, a Leonids expert who lectures at New York's Hayden Planetarium, also advocates 1999 as possibly the best year for a storm during this 33 year cycle. Writing for Sky & Telescope he says:
Based on what happened last November, I will venture a prediction. If a meteor storm is to take place at all, 1999 would appear to be the most likely year for it to happen. But even if this year's Leonids are richer in number, observers should not expect the same high proportion of fireballs that were seen in 1998. Instead, a more even mix of bright and faint meteors is likely.
Rao bases his argument on historical precedent and the Earth-comet geometry. During the seven most recent Leonid storms when Earth crossed Tempel-Tuttle's orbit soon after the comet, the average distance between the comet and Earth was 0.0068 astronomical unit. The average number of days between the comet's passage and the Earth's arrival at the plane of the comet's orbit was 602.8 days. With the 1999 values of 0.0080 AU and 622.5 days, Rao says we ought to be in a prime position to see significant, if not storm-level, activity.
Rao is also a meteorologist for News 12 Westchester, which seems a suitable occupation for predicting meteor showers.
In 1999, the Earth will pass nearly three times as far from the comet's orbital path as it did in 1966 and more than six times farther than it did during the great storm of 1833. If the peak of the Leonids arrives exactly when the Earth passes through the comet's orbital plane, Donald Yeomans of JPL gives 01:48 UT on November 18, 1999 as the most likely time for the 1999 maximum. That would make Europe and West Africa the best places to watch the show. However, Leonid meteor showers frequently arrive much earlier or later than predicted, so any place on the globe could be favored.
If the peak of the Leonids occurs over Europe or the Atlantic Ocean, then observers in the USA could be in for an unusual treat. The Leonid radiant would just be rising over North America at the time. In the eastern US sky watchers would see a large number of earth-grazing meteors skimming horizontally through the upper atmosphere. "Earth grazers" are typically long and dramatic, streaking far across the sky.
Most experts agree that 1999 is the most likely year for a Leonids meteor storm during the current 33 year cycle. However, if 1999 turns out to be a disappointment, don't despair! There are other studies that suggest 2000, 2001 or even 2002 could be better years. The Leonids are simply hard to forecast.
If 1999 is the year, when should you look? Most experts predict that the Leonids peak will occur between 0100 and 0400 Universal Time on November 18th. However, it is important to remember that such predictions are always uncertain. The 1998 Leonid fireball display occurred nearly 16 hours before the predicted maximum! No matter where on Earth you live, the morning of November 18 will probably be the best time to look for Leonids in 1999. This is true even if morning where you live occurs much earlier or later than 0100-0400 UT.
Conventional wisdom says that meteor observing is always best between midnight and dawn local time on the date of the shower (November 18 in this case). For a shower or storm like the Leonids that might be relatively brief, it is best to start watching no later than midnight. In fact, when the author of this story went outside last year at midnight to view the 1998 Leonids, the shower was already well underway! With this in mind you may decide it's a good idea to begin observing even earlier, say, 10 p.m. on November 17.
In the coming weeks Science@NASA will post more stories about the Leonids with observing tips for meteor watching with the naked eye, video cameras and other types of recording devices. One thing seems sure, no matter where you live: The Leonids are coming and, on Nov 18, 1999 the place to be is outside, looking up!
You can look up this story complete with pictures, graphs and other internet links at:
http://science.nasa.gov/newhome/headlines/ast27oct99_1.htm
ON THE HORIZON
HOLIDAY PARTY – December 11th
Our annual Holiday Party will take place at Daimon’s Clubhouse, 909 Plymrock Terrace on Green Bay’s West Side. We will meet at 6:00 PM for cocktails with dinner commencing at 6:30 PM.
Please mark your calendar now so you can help us celebrate the ending of a great year!