ASTRONOMY CLUB OF TULSA

Astronomy Club of Tulsa Meeting

Friday Aug 18, 2000 at 7:30 P.M.

Come at 7:00 PM to see sunspots and solar prominences from parking lot!

Where

Room M1 inside Keplinger Hall, the Science & Engineering Building at TU.

Enter the parking lot on the East Side of Keplinger Hall from

Harvard and 5th Street. This will take you directly toward the

staircase to enter the building. Room M1 is the first room on the left.

John Land

A billion tons of high-energy particles are hurtling through space at a million miles per hour directly toward EARTH!

Sound like the teaser for the next blockbuster disaster movie?  In fact we have had at least five such events this summer. Our Sun is the source of these incredible Solar Blasts! At our Friday Aug. 18th meeting we will be learning more about our fascinating Daytime Star. Come Early! ! We will have several telescopes set up to view sunspots. The Tiners also have a new H-Alpha filter that will allow us to observe those mysterious prominences that drift like giant spider webs above the sun. Maybe we'll get lucky and see a solar flare in progress. Our program will feature a video entitled "Solar Blast" revealing some of the latest knowledge about our Sun. You won't want to miss it!

In addition Dean Salmon will share with us some of his experience viewing and photographing an Aurora event this summer. Aurora (northern lights) are produced while high-energy particles from the sun collide with Earth's magnetic field. During the 89-91 Solar Maximum several aurora events were visible from the Tulsa area. So far this year we have had the bad luck of low latitude Aurora occurring during our daylight hours. The biggest event would have produced aurora as far south as Mexico if it had been at night! Dean will also be showing us how to use the bulletin board to post and read events at the club website.

Up coming Club meetings and events:

Below are tentative dates for our club meetings and star parties.

They may be subject to change if there is a conflict with the TU calendar.

Club Meetings: Friday Aug 18, Sept 15, Oct 13, Nov 10? TBA Club Dinner Dec 15

Club Observing Nights - Sat Aug 26 Workday starts at 3:30, Observing at Dusk

We will announce future club observing nights at the meeting.

We had at least 50 people at our July 30 Picnic and observing night. We all got to get a last glimpse of the "headless" comet Linear S4 as it was disintegrating. The Hubble Space Telescope has been able to detect at least six tiny comets resulting from its break up. Several of us got to find the asteroid Vesta - Planets - Uranus, Neptune and Pluto! These should still be accessible through Sept. We also got to see some really spectacular early Perseid meteors. Even with this week's bright moon you should be able to see several meteors through Aug 15th or later. Come to the next observing night to find out who has a new 17.5 inch Dobsonian.

Club Work Day - Sat Aug 26 - We have made great progress this summer correcting leaks in the dome and other repairs. We still have some yard work to complete and some water damaged sheetrock to replace. A big hand goes to Gerry Andries and Hugh Selman for repairing the stairs. K.C. Lobrecht for cleaning and painting the restroom floor. Butch and Donita Woodall for trimming the high grass near along the road. Gerry can still use some volunteers to help with the regular mowing. You don't need a mower to volunteer.

09-01-00 Fri 19:30 Girl Scout Troop 232 (15) girls will be visiting the observatory. To help Contact: Gerry Andries - 369-3320 gmandries@juno.com

Okie-Tex Star Party - Sept 24 to 30 Mile High Dark skies in Oklahoma Panhandle.

Okie-Tex has long been a favorite autumn retreat under the canopy of night. Since its move last year to the pristine ebony skies of the Black Mesa, Okie-Tex is rapidly becoming known as THE PLACE to be! Registration is only $30 per person plus $7.00 per meal. However you must get your registration and meals reserved by Sept 10th! Several of our members are already signed up so the HEATED bunkhouse beds are going fast.

Email - starpartyinfo@okie-tex.com Website http://www.okie-tex.com

Mail Okie-Tex Star Party, Box 128, Mustang, OK 73064

Observing Manuals Available

You can get started in astronomy with one to the Astronomical League Observing Projects. We have several of the "Universe Sampler" booklets to get you started learning the night sky. We also have a few of the "Messier Observer's" and "Herschel I " manuals for the more advanced or ambitious observers. These are available for $8.00 each. Plus we also have a list of the features to be observed to earn your Lunar Certificate for only $1.00.

For a look at these and other programs, check out the Astronomical League web site at: http://www.astroleague.org./al/obsclubs/obsclub.html or contact John Land at astroland@gbronoline.com or call 357-1759.

DAVID'S ASTRO CORNER

"Now You See It, Now You Don't"

By David Stine

That's about the best description for Comet Linear. One night it's glowing with a fantail and the next it disintegrates. It has been an amazing comet even though it only reached 6.5 Mg. The comet actually started breaking up the first week of July and then by the night of our star party and picnic it was nothing but a smear and all tail with no sign of a nucleus. What caused this breakup? Astronomers feel that intense solar heating triggered a massive disruption of the comets icy body. It's not that unusual for a comet to break up but the rapid disappearance is. The latest ground based images of Linear revealed no fragments brighter than 22nd Mg. Nothing is left except gas and dust. Fortunately for us we were able to view the comet at our annual summer picnic before it completely disappeared.

One thing that isn't disappearing is the intense activity on the Sun. The Sun continues to be a beehive of activity. If you view the Sun now you will think you have a dirty mirror with all the little dark spots all over it. Actually these are Sun spots many larger than the Earth. There isn't an area on the Sun that these spots are void. From these Sunspots come enormous flares that eject actual mass from the Sun. These are called Coronal Mass Ejection's. When these ejections impact the Earth, then we have radio interference, satellite drag, and even some brown and black outs. The good thing that comes from these impacts is the beautiful auroras they produce. When we have heavy geomagnetic storms, auroras can be seen even as far south as Oklahoma and Texas. Unfortunately we haven't seen any like this so far this year, however in 1989 you could go outside even in urban Tulsa and see the pinkish glow and the dancing white curtains in the northern sky. There are several websites that give you up to the minute information on the suns activity and aurora activity. For a brief forecast go to www.spaceweather.com. This site will give you Space Weather Current Conditions, which include the solar wind velocity and density, the sunspot number for the day, a recent photo of the Sun showing the sunspots, and a coronal hole photo. They also forecast possible solar flares for the upcoming week. The site gives a brief story on anything concerning space such as auroras, meteor outlook, and even comet news. Now if you want to follow the action on the sun go to the site http://sohowww.nascom.nasa.gov/data/realtime-images.html. Here you can view actual real time pictures of the sun and be updated every five minutes. At this site you can even download a real time screen saver that continually shows you what is happening on the Sun at a given moment. I have even been able to watch huge flares and coronal mass ejection's as they develop on this screen saver. If you go to http://www.spacew.com/www/aurora.html, you can see the latest aurora activity and whether it might be possible to view this far south. One last site is really innovated and could be helpful in alerting you to possible auroras. It is set up for central Illinois but it could still be useful for us. The site http://angwin.csl.uiuc.edu/~haunma/aurora/midwest.html, alerts you by e-mail when instrument sensors actually detect an aurora. This is in Illinois, but it still could be useful in alerting you that an aurora is in progress in Illinois and could possibly been seen in Oklahoma if intense enough. One of our members Joe Dillinger came across this site. There will be a discussion on solar activity at our August meeting, so you don't won't to miss it. We may be able to show you some of these sites.

One last thing before I close, if you haven't viewed the beautiful pairing of Jupiter, Saturn, Aldebaran, the Hyades open star cluster and the Pleiades open star cluster with the constellation Orion below and bright Capella in the Auriga constellation to the North, you are missing the reason you are in astronomy. It is a beautiful site and must be viewed before dawn interferes. Just look to the East for an unforgettable experience between 5 and 6 a.m. This sight can be viewed in Tulsa and no telescope is needed.

That's it for this month's Astro Corner, for astronomical updates contact me at dstine@exposquare.com.

And I will add your name to the astro e-mail group. Dream to observe the stars, observe to see the dream.

DAVIDS ASTRO CORNER UPDATE

The Hubble Telescope has done it again. This remarkable scope has found what is left of Comet Linear. Linear didn't just disintegrate it had babies. Hubble discovered not just one piece of the comet but also a shower of glowing mini-comets with tails. At least 6 mini-comets were clustered in the elongated stream of dust. There was one piece that was larger and brighter than the others and may be the parent nucleus for the smaller fragments. Hal Weaver, John Hopkins University astronomer stated that it will be important for large ground based telescopes to try and see the mini-comets as they spread apart, which could lead to a better understanding of the structure of the nucleus and the fragment sizes. Hubble is providing views of the disintegrating comet at a level of detail never before seen in a comet. If you go to the website http://science.nasa.gov/headlines/y2000/ast07aug_1m.htm?list, you can view the mini comets.

August SKY FORUM

By Don Cole

Star, large celestial body composed of gravitationally contained hot gases emitting electromagnetic radiation, especially light, as a result of nuclear reactions inside the star. The sun is a star. With the sole exception of the sun, the stars appear to be fixed, maintaining the same pattern in the skies year after year. In fact the stars are in rapid motion, but their distances are so great that their relative changes in position become apparent only over the centuries.

The number of stars visible to the naked eye from earth has been estimated to total 8000, of which 4000 are visible from the northern hemisphere and 4000 from the southern hemisphere. At any one time in either hemisphere, only about 2000 stars are visible. The other 2000 are located in the daytime sky and are obscured by the much brighter light of the sun. Astronomers have calculated that the stars in the Milky Way, the galaxy to which the sun belongs, number in the hundreds of billions. The Milky Way, in turn, is only one of several hundred million such galaxies within the viewing range of the larger modern telescopes. The individual stars visible in the sky are simply those that lie closest to the solar system in the Milky Way.

The star nearest to earth and the solar system is the triple star Proxima Centauri, which is about 40 trillion km (about 25 trillion mi) from earth. In terms of the speed of light, the common standard used by astronomers for expressing distance, this triple-star system is about 4.29 light-years distant; light traveling at about 300,000 km per sec (about 186,000 mi per sec) takes more than four years and three months to travel from this star to earth (see Light-Year below).

Physical Description

The sun is a typical star, with a visible surface called a photosphere, an overlying atmosphere of hot gases, and above them a more diffuse corona and an out flowing stream of particles called the solar (stellar) wind. Cooler areas of the photosphere, such as the sunspots on the sun, are likely present on other typical stars; their existence on some large nearby stars has been inferred by a technique called speckle interferometry. The internal structure of the sun and other stars cannot be directly observed, but studies indicate convection currents and layers of increasing density and temperature until the core is reached where thermonuclear reactions take place. Stars consist mainly of hydrogen and helium, with varying amounts of heavier elements.

The largest stars known are supergiants with diameters that are more than 400 times that of the sun, whereas the small stars known as white dwarfs have diameters that may be only 0.01 times that of the sun. Giant stars are usually diffuse, however, and may be only 40 times more massive than the sun, whereas white dwarfs are extremely dense and may have masses about 0.1 times that of the sun despite their small size. Supermassive stars are suspected that could be 1000 times more massive than the sun, and, at the lower range, hot balls of gases may exist that are too small to initiate nuclear reactions. One possible such brown dwarf was first observed in 1987, and others have been detected since then.

Star brightness is described in terms of magnitude. The brightest stars may be as much as 1,000,000 times brighter than the sun; white dwarfs are about 1000 times less bright.

Star Catalogs

Except for the comparatively few stars visible to the naked eye, stars are named by numbers according to the various star atlases and catalogs issued by astronomical observatories. The first such star catalog was compiled by the Egyptian astronomer Ptolemy in the 2d century ad. Called the Almagest, it listed the names and locations of 1028 stars. In 1603 a star atlas was published in Augsburg by the German astronomer Johann Bayer (1572-1625). Bayer listed a much larger number of stars than did Ptolemy, and he designated stars by a Greek letter and the constellation, or the celestial configuration, in which the star appears.

In the 18th century the English astronomer John Flamsteed also published an atlas in which stars were named according to their constellation, but Flamsteed differentiated them with numbers rather than letters. This atlas contained the locations of approximately 3000 stars. The first modern star catalog, that issued in 1862 by the observatory of Bonn, Germany, contains the locations of more than 300,000 stars.

In 1887 an international committee began work on an elaborate star catalog. The charts were to be compiled from photographs taken by about 20 collaborating observatories and comprising some 21,600 individual plates. From these photographs an exhaustive catalog is to list between 8 million and 10 million stars.

Modern catalogs of stars consist not of books, but of copies of glass photographic plates taken with large wide-field telescopes. The first such major survey was completed in the mid-1950s, using the 48-in. (122-cm) Schmidt telescope on Mount Palomar. Each plate covers a region of the sky 6‹ by 6‹, and 1035 charts cover all the sky visible from Mount Palomar. A corresponding set of charts of the southern sky is currently being made with the use of Schmidt telescopes in Australia and Chile.

*** Astronomy Dictionary***

Light-Year: A unit of length sometimes used to measure vast distances. It is equivalent to the distance that light travels in a mean solar year. At the rate of approximately 300,000 km/sec (186,000 mi/sec), a light-year is equal to 9,461,000,000,000 km (5,880,000,000,000 mi).

So until next month Dark Skies and Steady Seeing to You ...