B.C.A.A.S. MEETING AGENDA
September 9, 1999 7:30 P.M.
Reading Public Museum
Well, most of us couldnt be present for last months total solar eclipse, but our representatives did make the trip. Experience the solar eclipse presentation of Paul Becker and Lee Zelley as they share their views on the last one in this millennium.
October 14, 1999 7:30 P.M.
Reading Public Museum
Barry Shupp has really done it this time, he scheduled a great Mars mission presentation to be given by a member of the HST. Thats Hubble Space Telescope. Dont miss the latest updates from someone in the know.
In this issue:
2. Magazine Renewals
3. It's Calendar Time
4. SETI @ Home
5. DR. Seuss explains computers
Pegasus is a bimonthly publication of the Berks County Amateur Astronomical Society
Editor/Desktop publisher: Bob Capone, Joanne Reigle.
E-Mail submissions may be made to: BobC1957@netcarrier.com
September 4 & 5 - Mega Meet at Pulpit Rock
September 14 - 6:30 P.M. Orwigsburg Masons talk and star party
October 9 - 11:00 A.M. to
Discover your Museum Day Reading Public Museum We will need plenty of volunteers!
October 8 thru 10 - Spruce
Join George Babel on a trip to Spruce Knob, West Virginia for some nights of dark sky observing at the highest spot in the State.
October 15 - 6:30 P.M. Public
Starwatch at the Berks County Heritage Center
Rain/Cloudout Date is Saturday October 16, same time
October 15 - 6:30 P.M. - Cornwall Terrace Elementary Boy Scout Star Party
MAGAZINE RENEWAL TIME
Its that time of year again when you need to renew your subscriptions to Astronomy and Sky & Telescope. Sky & Telescope has gone up to $29.95. I called Kalmbach to ask if they intend to raise the subscription to Astronomy by the end of the year and I was told that they do not PLAN to increase the subscription. Therefore, it SHOULD be safe to collect the same $29.00. I emphasized those words because this is what they usually tell me, then change the cost anyway AFTER Pegasus is mailed.
In order to renew your subscriptions, I need either the money or a check payable to BCAAS at the September or October meeting. If you do not subscribe to either magazine but would like to since you can now get it at a discount. you may subscribe at any time during the year, however this would be a good time because most of our members have their subscriptions effective January.
ITS CALENDAR TIME AGAIN!
Astronomy wall calendars are once again available. If we can put together an order of 12 or more, we get a 50% discount!! The full price of the calendar is $13.00, so if you want to have a calendar for the year 2000, it will only cost $6.50. I will send the order to Kalmbach in the beginning of November. So again, I need the money at the September/October meeting.
If you decide you want a calendar, after Ive sent the main order in, you can still get it at a really good discount. It just wont be 50%.
MYTHOLOGY OF THE NIGHT SKY - Lyra
Lyra the harp, was placed in the heavens because of the heavenly music it played. This fabled instrument was invented by Hermes and given to his half-brother Apollo, who in turn transferred it to his son Orpheus, the musician of the Argonauts. Yes, this is the same Orpheus who appears in the classical story "Orpheus in the Underworld". It was the music from this harp that caused his wife Euryd ice to be released from Hades. (Okay, all of you who know the story - I KNOW it had a tragic ending. But that wasnt the harps fault!) An occasional early title for this constellation was Aquilaris, referring to the fact that the instrument was often shown hanging from the claws of Aquila the Eagle. In Bohemia, the stargazers also saw an instrument, however they saw a fiddle. In fact, they called the constellation "Fiddle in the Sky".
Other than musical instruments, the other major category of designations for this grouping of stars involves animals. The Peruvians called it the Ram in charge of the heavenly flocks. Some Arabs called it the Mule. (Now, how would Arabs know what a mule looks like? I thought they only rode camels). In ancient India, they saw an Eagle. In Akkadia, it was Urakhga, the great storm-bird.
While I have been concentrating on the legendary history of this constellation, let me finish by mentioning some astronomical trivia. It was in the stars of this constellation, northwest of Altair, that Professor Edward E. Barnard discovered a comet from its trail on a photograph taken at the Lick Observatory on October 12, 1892. This was the first comet ever discovered by the camera.
SETI @ HOME
I found an intriguing site on the web. Its called SETI @ Home.
The web address is : http://setiathome.ssl.berkeley.edu/
You might be wondering, "What it is?". It's a way for you, as a computer astronomer, to do some real radio astronomy.
Everyone has heard of SETI before? Search for Extra Terrestrial Intelligence. Well the astronomers at Berkeley started out doing their research by themselves. They soon realized that the job of crunching all the data was too overwhelming. The price of building a dedicated computer was also out of the budget. The astronomers needed as way to crunch the data without using a large computer. They came up with a plan. What if they took all the data and split it up into smaller blocks, called work units, then left a lot of smaller computers crunch the data and send it back. This way they would only have to verify a block of data that looked like a possible contact. If a suspected signal looked promising, they would run tests and back up observing runs to verify the signal.
As of right now, there are over 1,000,000 home PC's working on the work units that the group produces. Myself, included. The web site has a vast array of explanations as to how the system works; but, I will try to give you a quick over view.
The Arecibo radio telescope in Puerto Rico is the main telescope used for the SETI search. Whenever the telescope gets time it does a run and collects about 35 gig (35 billion) bytes of data a night. Former SETI attempts had dedicated, powerful, expensive computers doing the data crunching. This is very reminiscent from the movie Contact. What the Berkeley team does, it takes the 35 gigs of data and breaks it up into 300,000 byte blocks. You, as the home user, download a free program from their web site, and after installing it, gets a block of data and starts to work on it. You can have it run in the background all the time, or set it up as a screen saver. That way, you only crunch data when your screen saver is running. I run mine in the background and have had no problems with it. Once you start a data set, your computer will have done 175 billion calculations by the time it's done! To give you an idea as to the time it takes. I have a 400 MHz Pentium II and it takes about 13 hours to crunch 1 block of data. The average is about 27 hours. A slower computer will take longer to run the data. A little radio telescope icon is displayed in your system tray. When it's done it flashes red, then green. You can, then, connect to the Internet and get another block of data to work on. It's that simple.
So far, with everyone's help, this is what they've been able to accomplish!
Last updated: Mon. Aug 30 00:00:22 1999 UTC
|Total CPU time||59,223.41 years|
|Floating Point Operations||3.732045e+19|
|Average CPU time per work unit||27 hr 48 min 08.3 sec|
This would not have been possible without everyone's help.
If you're interested in having your computer do some "real" astronomical number crunching, log onto the web site, download the program and start crunching. Beam me up Scotty!
DR. SEUSS EXPLAINS COMPUTERS
If a packet hits a pocket on
a socket on a port,
and the bus is interrupted as a very last resort,
and the address of the memory makes your floppy disk abort,
then the socket packet pocket has an error to report.
If your cursor finds a menu
item followed by a dash,
and the double-clicking icon puts your window in the trash,
and your data is corrupted cause the index doesnt hash,
then your situations hopeless and your systems gonna crash.
If the label on the cable on
the table at your house,
says the network is connected to the button on your mouse,
but your packets want to tunnel on another protocol,
thats repeatedly rejected by the printer down the hall,
and your screen is all distorted by the side effects of gauss,
so your icons in the window are as wavy as a souse,
then you may as well reboot it and go out with a bang,
cause as sure as Im a poet, your systems gonna hang.
When the copy of your
floppys getting sloppy on the disk,
and the microcode instructions cause unnecessary risk,
when you have to flash your memory and try to RAM your ROM,
Quickly turn off the computer and be sure to call your mom.
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 editor of Pegasus.
Article 2, Stellar Distance and the Parallax Method
In the previous article we discussed stellar brightness, both apparent and real brightness. Apparent brightness can readily be measured, but to determine the star's real brightness (absolute magnitude) we need to first determine it's distant from us. In this article, the parallax method of determining stellar distance will be discussed. The parallax method of distance determination is the first and most fundamental scale of stellar distance measurement. All other distance scales rely on this fundamental scale.
To measure stellar distance astronomers rely on a phenomenon called parallax. This phenomenon can easily be demonstrated by looking past a nearby object, toward a very distant object. For example, hold your finger at arm's length and view the position of it against a distant wall using your right eye. Then close your right eye, open your left eye, and observe how your finger appears to shift it's position laterally relative to the more distant wall. The apparent shift in position of the nearby object based on two viewing locations is called the object's parallax. And this is the method used to determine the distance to nearby stars. From the measured amount of parallax shift and the known distance between the two viewing locations, the distance to the nearby object can be calculated by using simple trigonometry.
Stellar parallax or the lateral shift of a nearby star relative to more distant ones, is performed by watching the shift of the star's position from two different viewing points. The measurement units are typically in very small fractions of angle, called arc seconds. Traditionally this measurement was performed by comparing the views while the earth was at opposite sides in it's orbit around the Sun. This base line enabled the measurement of stellar distances for stars out to about 100 light years distance. More recently stellar parallax has been measured by satellite. The Hipparcos satellite, launched in 1989, measured the parallax of stars out to distances of about 1,000 light years. Thus one can see that parallax, either from earth observation or satellite, is only capable of measuring distances to relatively nearby stars, e.g. stars well within the galaxy and relatively close to the Sun.
Because of the limitations of the parallax method, other distance scales have been devised to measure stellar distances well beyond 1,000 light years distance. The methods of Cepheid vari-ables, spectroscopic parallax, and the more recently devised Type Ia Supernova scales are examples of other stellar distance scales. Suffice it to say that all of these distance scales are calibrated from the parallax scale. Much can be said about determining stellar distances by these other methods, and more will be discussed in future articles when longer distance scales are required.
Now that we can measure the distance to a star by using the parallax method, we can calculate it's true brightness or absolute magnitude by using the inverse square law (refer to Article 1 in this series.) In the next article of this series will discuss stellar color. After we understand the properties of brightness and color, we can begin to describe stellar populations and then begin to decipher their evolution.
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