Pegasus
Volume XXVI Number I
January /February 2000
Upcoming Highlights
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...". I’ll let
Bruce finish that, but I’m sure it will be an exciting
journey!!
In this issue:
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
President's Message
Welcome to the year 2000!
I’ve 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. We’ll have many good programs and
activities for all ages. We’ll continue with the old
successes, and try some new things. I urge you all to
become involved in YOUR club. I’d 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 let’s 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 don’t have to wait
any longer. If you have seen one, it’s 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 we’ll 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. Don’t be shy. Remember, this is not
the Met. This is BCAAS. We’re 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. That’s two out of one
hundred and twenty people in our organization that wanted to
make our newsletter more enjoyable to browse.
I’m 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 club’s web site.
- Set up a Star Watch and
coordinate it with the club.
- Help out at one of the
club’s 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 it’s 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 club’s
officers.
- Use your imagination,
I’m sure that there’s 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.
Mike
Bashore
A Layman’s 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 star’s color in
addition to it’s 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 star’s temperature
from a distance, simply by measuring it’s 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 Wien’s 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.
Ron
Kunkle
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 didn’t 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.
Linda Sensenig
Back
to Mythology
Kudos
Last but not least, I’d
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
George’s right hand man and also did and excellent job.
What else can be said about Dave well, we’ll 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.
Bob Capone
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