ASTRONOMY CLUB OF TULSA

OBSERVER

E-mail version

May 1999

ACT, Inc. has been meeting continuously since 1937 and was incorporated in 1986. It consists of approximately 150 members and is a nonprofit; tax deductible organization dedicated to promoting, to the public, the art of viewing and the scientific aspect of astronomy.

WHAT:

The Astronomy Club of Tulsa Meeting

WHEN:

Friday May 28, 1999 at 7:30 P.M.

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.

FUTURE MEETINGS:

June 25, July 30, and August 27

THIS MONTH'S PROGRAM:

Dr. Steve Balog will be speaking on the subject of "Black Holes". Steve has been into both amateur and professional Astronomy for over 25 years. He has a Ph.D. in Particle Astro-Physics and has done considerable research into the nature and theory of Black Holes. He is an Instructor at St Marks School in Dallas, Texas and is both the Planetarium director and Observatory director. He also serves on the Board of Directors of the Texas Astronomical Society. Steve is an excellent and dynamic speaker. I am very excited about having him as our guest speaker this month!

LAST MONTH'S PROGRAM:

I was honored, as your new president, to get to speak on the subject of Astronomical Software. I enjoyed demonstrating a number of very interesting Astronomy programs that can be ran on a standard PC. I gave out the web addresses where a large number of the programs, I demonstrated, can be downloaded for free. If you did not get the opportunity to write down the URL's, they can be found on the clubs web site. The Astronomy Club of Tulsa's web address is listed on the last page of this newsletter.

A WORD FROM THE PRESIDENT:

It was a real delight to have the opportunity to attend the Texas Star Party. Scott Parker and myself arrived at about 10:00 AM Sunday the 9th and stayed until the following Sunday the 16th. There were 594 registered participants this year and I'd guess about that many telescopes. The largest telescope, that I'm aware of, was a 36 inch. We enjoyed almost perfect skies every night except the last night when it clouded over shortly after midnight. One other night had a few clouds for a while but the rest of the week was great! The very dark, dry, skies of the Davis Mountains in West Texas are really a treat for anyone who loves Astronomy. I observed Omega Centauri, the brightest globular cluster in the sky, like I've never seen it before! Wayne Johnson, president of the Orange County Astronomers in California, and I observed together through my 17.5 inch telescope for two nights. Wayne is currently the discoverer of six supernovae. Using my telescope with digital encoders linked to "The Sky" (computer software), He and I hunted for a seventh discovery until dawn both nights. We didn't find a new supernova, but we really had a lot of fun!

On Friday and Saturday evening TSP gave away a number of prizes. Scott Parker won $50.00. I know he was happy about that!

SCHEDULED EVENTS:

On Friday Night, June 11th, the ACT Club star party will be held at the RMCC Observatory. All club members, their families, and friends are welcome. The sun sets at 8:41 PM that evening, so the Observatory facility should be open by about 8:15 PM for everyone who wants to set up their personal telescope. For directions to the Observatory or in case of poor weather call Gerry Andries at: 918-Phone.

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DAVID'S ASTRO CORNER

By David Stine

When was the last time you could go in your backyard and view a comet? It has been quite a long spell since that was possible, but for a few weeks that wait is over. Steven Lee, an amateur astronomer, discovered Comet Lee while at a star party near Mudgee, New South Wales in April. Circumstances were very similar to the way Comet Hale-Bopp was discovered. This comet will in no way get as bright as Hale-Bopp, but it is beginning to shape up as a decent backyard telescope comet. Comet Lee is to reach perihelion on July 11, 1999. At that time, the long period comet will be at a distance of 0.71 AU, which is about the distance of Venus from Earth. The downside is that it will be on the other side of the sun and not visible at that time. Now is your best shot at viewing Lee. The comet is traveling very fast northward at this writing and is already reported to be brighter than Mg. 7., which already has exceeded earlier predictions. Rusty Fletcher, our fearless leader, observed the comet at the recent Texas Star Party and reported it as quite bright with a small faint tail. On the night of May 19, K.C. Lobrecht reported that from the RMCC Observatory, that Comet Lee was just gorgeous. It was like M13 and better than Mars. According to K.C. it will blow you away in weeks to come. She did say she felt it was moving even more rapidly than predicted and that the coordinates are off by a degree or so. She estimated it to be as bright as Mg. 6.9. For the next two weeks, Lee is expected to brighten even more, possibly reaching naked eye visibility by the end of June. By mid June it will move into Cancer, but start getting lower on the horizon. In early July it will be its brightest, somewhere between 6th and 7th Mg., but it will be quite low in the evening sky. By the 10th, Lee will be lost in the sun's glare. After perihelion, Comet 1999 H1 Lee, will return to view in the early morning hours in August. By August 11th, Lee will be visible prior to morning twilight and will have faded to about Mg. 7.6. August 15th, it will be moving through western Auriga. By September, although faded to Mg. 8.5, it will become a circumpolar object, viewable all night long. In October it will be high in the sky by 11p.m. in Andromeda at Mg. 9.3. Then by the end of the month it will have passed into Pegasus, and fade rapidly to 12th Mg. by mid November. But for now, on May 28th, ACT Club meeting night, the comet will be below the stars that make up the head of Hydra in the West. I will bring my telescope to the meeting and we can view it afterwards. Below are coordinates for the comet from May 28th through June 8. These are the latest, but could change a degree or so depending on how fast the comet moves. MG. estimates are already incorrect so I did not list them. Comets can be very unpredictable when it comes to brightness predictions as this one has already exceeded brightness predictions. Again I warn, don't expect to see a Comet Hale-Bopp, that was an unusual comet, but Lee will not disappoint. Additional information and the latest updates on Comet Lee can be obtained at the following website: http://antwrp.gsfc.nasa.gov/apod/ap990427.html. I will also have a few copies of Comet Lee's path through the sky at the meeting for those interested in tracking this visitor from deep space.

C/1999 H1 (Comet Lee)Orbital Elements: T 1999 July 11.1652 TT, Q=0.708294, E=1.0,
Peri.=40.6733, Node=162.6417, Incl.=149.3545

The following coordinates are the latest for Comet C/1999 H1 (Lee)

May 28: 8hrs38.8min RA, -0deg35min dec
May 29: 8hrs37.6min RA, 0deg36min DEC
May 30: 8hrs36.4min RA, 1deg45min DEC
May 31: 8hrs35.2min RA, 2deg51min DEC
June 1: 8hrs34.1min RA, 3deg54min DEC
June 2: 8hrs33.1min RA, 4deg55min DEC
June 3: 8hrs32.0min RA, 5deg54min DEC
June 4: 8hrs31.1min RA, 6deg51min DEC
June 5: 8hrs30.1min RA, 7deg46min DEC
June 6: 8hrs29.2min RA, 8deg38min DEC
June 7: 8hrs28.3min RA, 9deg29min DEC
June 8: 8hrs27.4min RA, 10deg19min DEC

A quick update on Ron Woods - he is gaining strength and feeling better. The doctor says blood vessel growth is continuing but hasn't set a date for the skin graft. His eyelid skin graft is slowly healing. In sum, Maura says healing continues and they will be thrilled when he finally gets the skin graft. Thanks for all the cards and letters.

That's its from my Astro Corner this month.

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CSAS Star Party

Are you planning a family vacation for this summer and want to incorporate some spectacular observing? Come to Colorado in July!!

You are invited to join the Colorado Springs Astronomical Society at the 13th annual ROCKY MOUNTAIN STAR STARE, July 8-11. This is one of the biggest amateur gatherings in the Rocky Mountains, with over 300 observers expected this year. This year's site is at an elevation of nearly 9000 feet, about an hour's drive west of Colorado Springs. Also featured this year is the Astronomical League's MARS South regional meeting. (MARS stands for "Mountain Area Research Section")

We are located in the heart of Colorado, with lots of nearby attractions,

including fishing, hiking, site-seeing, white-water rafting, and everything else that makes Colorado a wonderful vacation destination. If you visit the Colorado Springs area over the 4th of July holiday, you can even check out the highest road race in the country - the Pikes Peak Hill Climb - that takes brave drivers to over 14,000 feet of elevation.

If you would like to learn more, please visit the RMSS page from our web site: http://members.aol.com/bygrens/CSAS.html

There you will find everything you need, including driving directions, camping suggestions, tentative speaker and events schedules, and our pre-registration instructions. We look forward to seeing you this summer in Colorado!

Steve - CSAS webmaster bygrens@aol.com

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May SKY FORUM

By Don Cole

Neptune is the fourth largest of the planets in the solar system, and eighth major planet in order of increasing distance from the sun. The mean distance of Neptune from the sun is 4.5 billion km (2.796 billion mi), and its mean linear diameter is approximately 49,400 km (approximately 30,700 mi), or about 3.8 times that of the earth. Its volume is about 72 times, its mass 17 times, and its mean density 0.31 that of the earth (about 1.7 times that of water). The albino of the planet is high; 84 percent of the light falling on it is reflected. The period of rotation is about 16 hr, and the period of revolution about the sun is 164.79 earth years. The average stellar magnitude (see Magnitude below) of the planet is 7.8, and it is therefore never visible to the naked eye, but it can be observed in a small telescope as a small, round, greenish-blue disk without definite surface markings. The temperature of the surface of Neptune is about -218 degrees C (-360 degrees F), much like Uranus, which is more than 1 billion miles closer to the sun. Scientists assume, therefore, that Neptune must have some internal heat source. The atmosphere consists mostly of hydrogen and helium, but the presence of up to three percent methane gives the planet its striking blue color.

Approximately eight known satellites orbit Neptune, two of which are observable from earth. The largest and brightest is Triton, discovered in 1846, the same year Neptune was first observed. Triton, with a diameter of 2705 km (1680 mi), is only slightly smaller than earth's moon. It has a retrograde orbit-that is, it moves in the opposite direction to the planets direction of rotation - unlike any other major satellite in the solar system. Despite its extreme coldness, Triton has a nitrogen atmosphere with some methane and some form of haze, and it displays an active surface of geysers that spout an unknown subsurface material. Nereid, the second satellite (discovered in 1949), has a diameter of only about 320 km (about 200 mi). Six more satellites were discovered by the Voyager II planetary probe in 1989. Neptune is also circled by five thin rings. Its magnetic field is tilted more than 50 degrees to the rotation axis.

The discovery of Neptune was one of the great triumphs of mathematical astronomy. In order to account for perturbations in the orbit of the planet Uranus, the French astronomer Urbain Jean Joseph Leverrier in 1846 calculated the existence and position of a new planet. That same year the German astronomer Johann Gottfried Galle (1812-1910) discovered the planet within 1 degree of that position.

*** Astronomy Dictionary ***

(Magnitude), term used to designate the apparent brightness of a star as viewed from the earth. The ancient Alexandrian astronomer Ptolemy originally divided all visible stars into six magnitudes: the brightest were called first magnitude, those barely visible to the naked eye were called sixth magnitude, and the other visible stars were assigned intermediate positions. In the 19th century a standard system was finally adopted under which a star of any given magnitude is 2.512 times as bright as a star of the next higher magnitude; thus, for example, a star of the second magnitude is 2.512 times as bright as a star of the third magnitude. The advantage of this particular magnitude ratio, 2.512, is that it coincides closely with the Ptolemaic system; and because 2.512 is the fifth root of 100, a star of the first magnitude is exactly 100 times as bright as a star of the sixth magnitude, a star of the sixth magnitude is exactly 100 times as bright as a star of the 11th magnitude, and so on. Stars brighter than magnitude 1.5, of which there are 20, are called first-magnitude stars. Thus, the first- magnitude star Aldebaran has an actual magnitude of 1.1; the slightly brighter first-magnitude star Altair has a magnitude of 0.9. The brightest stars are brighter than magnitude zero. Sirius, the brightest star outside the solar system, has a magnitude of -1.6. The sun has a magnitude of -26.7, inasmuch as it is about 10 billion times as bright as Sirius in the earth's sky.

(Absolute magnitude), as opposed to apparent magnitude, indicates the brightness that a star would have if it were placed at a distance from the earth of ten parsecs, or 32.6 light-years. By rating stars in this way, astronomers are able to compare them with respect to intrinsic brightness. The sun, for example, has an absolute magnitude of +4.7.

*** From The Cargo Bay ***

Why are the Orbiter cargo bay doors opened once they are on station (in orbit)? This is a vital first task, because the radiators that shed, get rid of, or radiate the excess heat generated by the Orbiter are located and actually built into the inner surface of the cargo bay doors. If the doors remain closed, heat builds up within the vehicle and the mission will have to be aborted within 8 hours. Once the thirty two latches are released the doors can be opened and all systems are up and running, the mission can last anywhere from 7 to 30 days are possible. Once the Orbiter is in orbit how does it maneuver in space?

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

Reference Material :: "Astronomy, A self-teaching guide." by Dinah L. Moche (4th ed.) "Guide to the Stars" by Leslie Peltier. " Astronomy, For the Earth to the Universe" by Jay M. Pasachoff (3rd ed.)

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Astronomy Club meeting dates for 1999.

The club will meet the last Friday of each month except for November and December when a holiday will interfere with the last Friday. The November meeting will be on the 19th, and the December meeting will be on the 17th.

The dates are:

28 May

25 June

30 July

27 August

24 September

29 October

19 November

17 December

That’s all folks…