January 13, 2000 7:30 P.M.
Reading Public Museum
The sky is falling! The sky is falling! Well Chicken Little was an alarmist, but Joe Varady being a rational astronomer has made a commitment to the collecting and study of meteorites. Joe will share his extensive knowledge about these exotic visitors from the cosmos with us this evening. If you would like some hands-on education, do not miss this great presentation.
February 10 2000 7:30 P.M.
Reading Public Museum
Our February program will be presented by our own Bruce Dietrich. Come and travel with Bruce to" The Greatest Places...". Ill let Bruce finish that, but Im sure it will be an exciting journey!!
In this issue:
2. Dues are due
3. Lunar Eclipse Observing
4. Announcing the first BCAAS talent Fest
5. What Can I Do to Make My Club Better
Pegasus is a bimonthly publication of the Berks County Amateur Astronomical Society
Editor/Desktop publisher: Bob and Joanne Capone
E-Mail submissions may be made to: BobC1957@netcarrier.com
Welcome to the year 2000! Ive anticipated this time in history since I was a kid. Dampened somewhat by all the Y2K hype, it still promises to be an exciting New Year for all of us! I look forward to a lot of good astronomy and fellowship with all of you. Well have many good programs and activities for all ages. Well continue with the old successes, and try some new things. I urge you all to become involved in YOUR club. Id like to thank past President George Babel for an excellent job done over the last two years, and also to thank him in advance for the help he will give me this year with programs and other things. So lets all get ready to make this one terrific B.C.A.A.S. year!!
-Barry L. Shupp
Dues are Due
If you have not already paid your dues for the year 2000, you will find a brightly colored renewal notice attached to this issue of Pegasus. If you receive one and you already paid, do not ignore it. Notify me. It means I have not marked my records that you paid. If you joined during the year 1999, your dues have been pro-rated to the end of 2000.
In order to avoid paying the $2.50 late fee, it is important that I receive your due by the end of January. If you cannot get to the January meeting (or if the January meeting should be snowed out), it is important for you to mail me a check payable to BCAAS.
Lunar Eclipse Observing
We had the brightest and largest full moon last month. What can we do to top that? How about the darkest full moon? If you have never witnessed this spectacle before, you dont have to wait any longer. If you have seen one, its time to reacquaint yourself. Either way, we will be getting together on Thursday, January 20, 2000 at the flying field to view this event starting at 7:00 P.M. until about 1:00 A.M. Dress warm and well see you there hopefully.
Announcing the first BCAAS talent Fest!
At the March meeting you will have an opportunity to participate in our first talent program. If you would like to participate but cannot sing or play a musical instrument, the talent presentation need not be musical. Perhaps you have a flair for comedy. Perhaps you like drama. Perhaps several would like to get together and perform a skit. There will be a piano available in our meeting room that night.
This talent fest will not be judged. No prizes for the winner. We are not interested in winning or losing. We just want to have a good time. Your performance need not be confined to an astronomical topic.
If you would like to participate, please contact me prior to the March meeting. I only need to know who is participating and the type of talent you are presenting. Dont be shy. Remember, this is not the Met. This is BCAAS. Were all friends.
What Can I Do to Make My Club Better For Everyone?
Over the past year I became involved with printing the Pegasus newsletter for our club. During that time it became quite aware to me that for the 120 copies of the newsletter I printed up every two months it was lucky if the editor received articles for each newsletter from more than two members. Thats two out of one hundred and twenty people in our organization that wanted to make our newsletter more enjoyable to browse.
Im not writing this article to gripe about our memberships non-participation, but rather to point out to all who read this that we can all do something for the club to make being a member of the BCAAS a fun and enjoyable interaction between people with similar interests. If each of us would do just one thing throughout the year, there would be a substantial increase in club activity.
You say to yourself, "what can I contribute that anyone else would wish to see or hear?" Let me list a number of items that would be greatly appreciated by the BCAAS general membership.
- Write an article for Pegasus about anything astronomically related no matter how simple or complex.
- Ask to add a section of your own to the clubs web site.
- Set up a Star Watch and coordinate it with the club.
- Help out at one of the clubs Public Star Watches.
- Do a program for one of our meetings or find a speaker for one of the meetings.
- Tutor a young astronomer and let everyone know how its going with an article for Pegasus.
- Find astronomy related events and add them to the web site or Pegasus and bring them up at our meetings.
- Put together handouts for our club events possibly describing what viewers might see through the scopes that evening.
- Help with club fund raisers
- Run for club officer or offer your assistance to one of our clubs officers.
- Use your imagination, Im sure that theres a universe of ideas out there
I am positively sure that when you become more involved with the club and its activities it will be more enjoyable for you and everyone else whom with you may come in contact. Make at least me happy and give a little of yourself and we will see how far we can go.
A Laymans Guide to Stellar Evolution
This article is part of a series dealing with stellar evolution. The articles are written by a layman to convey that understanding to others. To that extent, errors and omissions should be excused. The series will cover the formation of stars, their energy production, assemblages, and their deaths. For comments, please contact the author.
Article 3, Star Color (Surface Temperature)
The determination of the real brightness, or absolute magnitude, of a star was discussed in two prior articles. In this article we discuss the color property of stars. When we know a stars color in addition to its brightness, then it can be classified by type. Knowing the types of stars, we can then discuss their formation, energy production, and their deaths or end states. We will begin to describe the various types of stars in subsequent articles, but first we need to understand the color property of a star.
When one carefully observes stars, it becomes apparent that stars exhibit subtle differences in color. Many are bluish, such as is Rigel, while some are more white in color, like Sirius. Some, like our Sun, are yellowish. Others, such as Aldebaran are orange and some are decidedly reddish in color, e.g. Betelgeuse. These color differences are the direct result of the surface temperature of the star. The relationship between color and surface temperature is readily demonstrated by heating a piece of iron. As the iron bar begins to heat it glows red-hot. As it gets hotter, it turns orange, then yellow, until at its hottest it is white-hot.
The relationship between color and temperature of an object is due to the unique spectrum of radiation emitted by any object above absolute zero temperature. By measuring the emitted radiation spectrum of an object and determining at what color that spectrum peaks, one can effectively determine the temperature of the object. Thus one can effectively measure a stars temperature from a distance, simply by measuring its radiation spectrum. For those interested in further reading, the technical name of this type of spectrum is that of a black-body radiator, and the law that relates the peak of the spectrum to a temperature is called Wiens Law.
Stars are assigned a letter to designate their color class or surface temperature. They are assigned a letter from the sequence OBAFGKM where 0 type stars are the hottest, e.g. blue-white in color, and so on down to class M, for the much cooler, reddish stars. The corresponding temperatures associated with these colors range from 40,000 K down to about 2,500 K respectively. Our Sun is a class G, yellowish star with a surface temperature of about 5,800 K. Recently the classification sequence of stellar colors has been expanded to include the classes L and T, even cooler types of star then the class M. Note, a useful tool for remembering this color sequence is the phrase "Oh Be A Fine Girl, Kiss My Lips Tonight."
In the next article in this series, the Brightness and the Color (or surface temperature) of a star will be used to generate a population plot for a large group of stars. From this plot, called a Hertzsprung-Russell diagram, we shall be able to discern various types of stars and some details about their evolutionary sequence.
MYTHOLOGY OF THE NIGHT SKY - PERSEUS
It was a typical day in the life of our hero, Perseus. He was flying through the sky on Pegasus, his winged horse, coming home from an adventure. This particular day he was carrying the head of Medusala woman with a REALLY BAD hair day, so bad in fact that anybody who looked on her turned to stone. He had been required to present a Gorgon head and was fortunate enough to find the sisters sleeping. (SISTERS? There are more than one snake-haired woman? Wonder what happened to the others.) Being the clever hero that he is, he used a mirror to reflect her image so he didnt have to look at her. Then he cut her head off. Mission accomplished. Time to go home. Anyway, he was flying over the coast when he looked down and saw Andromeda, a really gorgeous, sexy princess, chained to the beach and lo and behold, there was a Cetus, a sea-monster heading straight for her!
"Never fear, Perseus is here!" He swooped down just as Cetus arrived, flashed the head of Medusa at the monster, turning the monster to stone, rescued the fair maiden and whisked her back to her family. In appreciation, Perseus was placed in the night sky. I think he would have preferred a gold shield or something.
In keeping with this theme, the star Algol is the head of the demon. In keeping with the hero theme, even the Christian constellations have this star formation named David with the head of Goliath. The constellation is 28 degrees in length, one of the most extended in the heavens, which is only appropriate for someone as heroic as Perseus. Argelander lists 81 naked eye stars in his star atlas. He also suggested that within the boundaries of Perseus may lie the center of the universe. I think that might be attributing a little bit TOO much grandeur to our hero.
Of interest to amateur astronomers is the double star cluster.
Back to Mythology
Last but not least, Id like to pass on our personal thanks to George Babel, outgoing president, completing his second year.
Over those past two years, he has been a driving force in promoting the clubs activities and public awareness of our existence. He has been instrumental in securing educational programs for our club meetings, as well as procuring ongoing star-watch events. His knowledge of telescopes and observing skills has been beneficial to new and old members. Those same skills have been pasted on to the public, on many occasions.
We also need to give our congrats to Dave Brown, outgoing vice president. He was Georges right hand man and also did and excellent job. What else can be said about Dave well, well leave that up to each of us that know him. Only kidding Dave, if I ever had to have one friend, it would be Dave.
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