PeGASus Newsletter Issue #61 – Nov. 1995

The PGAS meets next on November 29 at 7:30 PM Room 2-223 at CNC


CONTENTS

Editorial
Coming Events
In The Sky
Astronomy at the Museum
AstroSurfing
Membership Application Form
(not necessarily in that order)


The PeGASus is published monthly by the Prince George Astronomical Society. Contributions to the newsletter are welcome.

Send correspondence to: The PGAS 3330 – 22nd Avenue Prince George, B.C. V2N 1P8 or Aaquist@cnc.bc.ca

The PGAS is a nonprofit organization dedicated to the advancement of science and astronomy in the Prince George region and neighbouring northern school districts.

OUR PURSUITS ARE ASTRONOMICAL OUR ACTIVITIES ARE OUT OF THIS WORLD OUR AIM IS THE SKYOur observatory is located near West Lake on Tedford Road, 10 kilometres from Highway 16 down Blackwater Road. For hours of operation, call someone on the Executive. The observatory phone number is 964-3600. This is a party line, so a busy signal does not imply that someone is there.


PRINCE GEORGE ASTRONOMICAL SOCIETY EXECUTIVE, 1994/5

President: Jon Bowen 563-9869 Vice President: Bob Nelson 562-2131/563-6928 Secretary: Brian Potts 562-8113 Treasurer: Barb Hansen 962-7477

Members at Large:

Gil Self 964-7279 Eric Hansen 962-7477

Nominated Positions:

Technical Director: Bob Nelson Observing Director: Jon Bowen Building Director: Mike Hansen Promotional Director: Jennifer Whitman Financial Director: David Sundberg PeGASus Editor: Orla Aaquist


EDITOR’s COMMENTS

At October’s annual general meeting, Barb Hansen ran against Dave Sundberg for the position of treasurer, and Brian Potts ran against Mathew Burke for the position of secretary. For the two positions of member-at-large, we had four members running: Gil Self, Eric Hansen, Dave Sundberg, and Orla Aaquist. Even though I gave a passionate speech on my own behalf detailing all of my shortcomings, Dave and I were defeated by Gil and Eric.

In my mind, the outcome of the voting is not so important. What is more important is that the club has enough members who are willing to take an active part in the club’s activities. You do not need to be a member of the executive, or be one of the appointed directors, in order to become involved. You just have to have a desire to do something. For me, producing this newsletter is very enjoyable. It takes about one entire day to fill in the blanks and it takes another half day getting it printed, photocopied, and mailed out to you. I do not need to be on the executive in order to do this. Although Jon is trying to get me on the executive by creating another director’s position, there is no need to do this since it will not change what I am doing on behalf of the PGAS.

Because our club is growing, there is a great need for members to get involved. One way of doing this is to attract new members, because the more members we have, the greater is the chance that someone will be inspired to do something like plaster the walls, paint the walls, widen the driveway, build an observing deck, find us some money, host a neighbourhood star party, build a telescope, find some flooring, find some concrete, finish the basement, make an observatory sign, recruit new members, finish the darkroom, take some astrophotographs and make some postcards, make membership cards, start a youth group, learn how to use the club telescopes, teach others how to use the club telescopes, visit schools to show slides, hold public viewing sessions at UNBC, CNC, Fort-George Park, Civic Centre, and schools, look up at the night sky, build a bookshelf, frame some posters, share your thoughts about astronomy with other members, start an armchair astronomy session, start a

new-members learning group, develop a new-members’ information package, put together a promotion package, collect old astronomy books, search the library for interesting projects in astronomy, show the stars to your friends, build another picnic table, call a fellow member, catch the mice at the observatory, come up with a list of ideas of what the club should be doing, bring some friends out to the observator, count some meteors,


COMING EVENTS

If you are involved with any astronomical or otherwise scientific activity on behalf of the PGAS, please list the activity here.

Nov 25: If you get this newsletter on time, watch for a nice occultation occurs on the evening of November 25th, when the young crescent Moon overtakes 3rd-magnitude Rho-1 Sagittarii. See the map on page 80 of the January (?) issue of Sky and Telescope, but note the time tick should read 24:00 UT, not 23:50. You can call 301-474-4945 for updates or check out the WWW site http://www.sky.net/~robinson.

Nov 29: monthly meeting at the College of New Caledonia. The constellation of the month presentation is on Perseus. Afterwards, a video will be shown about the Shoemaker-Levy comet collision with Jupiter. Also discussed in this video is the risk we face from a similar collision with the earth. If it is clear, have a look at the first quarter moon through the college’s C8.

Dec 16: Christmas Party at someone’s house.

Dec 27: NO MEETING. No PeGASus.

Dec 13: Executive meets at the Xerox office. All members are welcome to attend and directors are requested to attend.

Dec 31: Mathew and Susan are getting married.

Jan 31: Monthly meeting at the College of New Caledonia. The constellation of the month presentation is on Orion. Afterwards, Bob Nelson will talk about variable stars.

Feb 28: Orla speaks on planetary nebulae.


A N N O U N C E M E N T S

If you have anything to announce or advertise, consider this space of the PeGASus. Welcome to the Club Catherine Verpaelst and Todd Whitcombe.

Thank You to all those who volunteered to help out at the Pine Centre booth during Science and Technology weekend. Participants were Don Goldie, Barb Hansen, Eric Hansen, Jon Bowen, Mike Hansen, Sean Ollech, Vince Hogan, Gerhard Bierman, Ted Biech, Gil Self, Steven Senger, Lance Odiorn, Mathew Burke and Shannon Austman. I sure hope I didn’t miss anyone. I think we had a really successful exhibit this year.

Belated Thanks to our one and only youth member, Sean Ollech, for spending some time at our P.G. Exhibition booth this summer. I think Sean was one of the few people who came out to help man the booth.

New Executive Al last month’s elections, a few changes to the executive was made. Barb Hansen was voted in as treasurer (replacing Dave Sundberg), and Brian Potts was voted in a secretary (replacing Mathew Burke). At an executive meeting following the annual general meeting, Mike Hansen took over the appointed position of Observatory Director from Eric Hansen, and Dave Sundberg was appointed for the new position of Financial Director.

Public Viewing Public viewing at the observatory will stop for the season at the end of November. They will begin again in the spring.

Membership Dues are Due Your annual dues of $20 are necessary in order to maintain this wonderful newsletter, pay the observatory’s utilities, and buy cookies.

Last Call for Calendars

At the start of November, Orla ordered 50 1996 Astronomy Calendars form the RASC in Vancouver. They are all sold. He will order more calendars, if there is a demand. Give him a call at 964-9626 before the end of November if you are interested. They are really nice calendars, and will make a great Christmas present. They are only $7.50 for members.

Darkroom is Developing The Fraser-Fort George Regional Museum has donated more darkroom equipment and chemicals. It looks like we have enough ‘stuff’ to build a working darkroom at the observatory. Gill Self estimates that we have acquired over $500 of materials from the museum. All we need now are sinks and a water supply. THANKS FFGRM.

Who wants to host this year’s Christmas Party on December 16?


ASTROSURFING

Details of the Science News posted here are available on the astronomy forum on the Prince George Free-Net.

NASA has begun flight testing an experimental aircraft wing panel that has Supersonic Laminar Flow Control (SLFC).

NASA physicists using the Ulysses spacecraft have obtained the first “snapshot,” of the spiral structure of our solar system’s magnetic field. These lines of magnetic force originate in the Sun and extend outward into the solar system. The aerial photo of the interplanetary magnetic field became possible with the flight of Ulysses over the south pole of the Sun in 1994. Now we could look down on the solar system.

Astronomers are now fairly certain that a planet is orbiting 51 Pegasi, a Sun-like, main-sequence star of spectral type G5 situated 42 light-years from Earth. Several observers have confirmed an announcement made by Michel Mayor and Didier Queloz of Geneva Observatory. The planet is lies only 7 million kilometers away from it – equal to just 1/20 of Earth’s distance from the Sun. Orbiting so close to the star, this world would be heated to 1,000 deg Celsius, and it’s likely a nearly molten ball of iron and rock. To create the observed wobble in 51 Peg’s spectrum, the planet needs a mass at least half that of Jupiter. 51 Pegasi is magnitude 5.5 and easily visible in binoculars; however, don’t expect to see the planet.

NASA’s Galileo spacecraft is proceeding toward its December rendezvous with Jupiter, with spacecraft engineers greatly relieved at last weekend’s test results showing that its onboard tape recorder remains functional. The suspicion is that part of the tape has weakened, causing it to slip in the transport mechanism.

Planetary astronomers recently got their first look at a crude compositional map of the asteroid 4 Vesta, thanks to images taken at several key wavelengths by the Hubble Space Telescope. Vesta, the third largest asteroid, is known to exhibit bright and dark markings. The new Hubble data suggests that one hemisphere is dominated a type of basalt similar to many lava flows on the Earth’s surface. The other half has the spectral signature of a basalt that solidified underground.

A team led by NASA researchers has devised a miniaturized sensor system that could be a catalyst for a revolutionary new generation of small, low-cost spacecraft to explore the solar system. The Planetary Inte-grated Camera-Spectrometer, or PICS, is ex-pected eventually to replace whole suites of individual spacecraft instruments. Its develop-ment represents a crucial step toward enabling future NASA missions that will have to use smaller launch vehicles and, hence, smaller spacecraft to travel to distant planets and other bodies in the solar system.

What some scientists are calling ‘the most dramatic images yet taken by the Hubble Space Telescope was presented at 3 p.m. EST, Thursday, Nov. 2, 1995, in the NASA Headquarters Auditorium, 300 E St. SW, Washington, DC. The images reveal dark pillar-like structures in the Eagle Nebula (also called M16). These structures are thought to be incubators for new stars and are called “EGGs” (Evaporating Gaseous Globules”).

An extremely lightweight camera and a variety of instruments designed to study daily weather patterns and the icy south pole on Mars have been selected by NASA officials to fly aboard an orbiting spacecraft and lander in late 1998, known as the Mars Surveyor ’98 Orbiter and the Mars Surveyor ’98 Lander.

The latest information about NASA’s Galileo Probe mission and other information about the solar system’s largest planet, Jupiter, is now available on the Internet. Information can be accessed on the World Wide Web at URL: http://ccf.arc.nasa.gov/galileo_probe/

Measurements of interstellar Helium have improved over the years to such an extent that various theories can soon be put to the test. Not only are cosmological theories at stake but various features of the standard model of particle physics.

Hubble will soon be joined in space by the Infrared Space Observatory built by the European Space Agency.

A huge interplanetary disturbance struck the Earth’s protective magnetic field on Oct. 18, producing a magnetic storm and auroral displays, or “Northern Lights” that persisted for two days. The phenomenon was visible in the United States as far south as Denver.

The Sun has passed through a series of Saturn-ring-plane crossings which began in May and August and will conclude in February. The crossing times have been coming late by at least 20 minutes. This means either the planet’s spin axis is precessing at only about 2/3 the predicted rate or, more likely, our knowledge of the pole’s location is off by about 2 arcseconds.


IN THE SKY ALGOL, THE “DEMON STAR” by Alan Whitman

The constellation Perseus represents a mythical hero. He carries the head of the monster Medusa, a gorgon with snakes for hair whose gaze turned men to stone (the origin of the phrase “a petrifying glance”). Perseus managed to avoid the monster’s eyes by looking at its reflection in his polished shield while slaying it. Medusa’s head is represented by Algol, the first star that 17th century astronomers noticed varying in brightness.

However, the classical identification of a bright variable star with the head of a demon strongly suggests that the variability was known in ancient times.

Algol consists of two stars orbiting their mutual centre of gravity, with the plane of their orbits nearly aligned with our line of sight to the system. Once every 2.9 days the brighter star of the pair is partially eclipsed when the larger but fainter companion star passes between the bright star and us. Dr. Bob Nelson studies similar eclipsing binary systems at the PGAO.

When viewing the sky with the unaided eye, most stars appear the same brightness night after night but not Algol, the demon star! Most nights Algol is as bright as Gamma Andromeda, to Algol’s right (west) on the star chart (see page opposite). Normally, Algol is about four times as bright as Rho Persei, the star just below (south of) Algol. When Algol is being eclipsed, it fades slowly for four hours. Then for two hours at mid-eclipse it is as faint as nearby Rho, before brightening again. You will find that Algol’s changing brightness is easily judged by comparing it with adjacent Rho.

Algol will be partially eclipsed and consequently be at minimum brightness for two hours centered on the times in the box at the end of this article.

Algol is not the only Perseus gem visible with your unaided eye in a dark sky. “The Double Cluster” is easily found as a hazy spot midway between the prominent arc of stars through Alpha Persei and the “W” of the constellation Cassiopea. Binoculars will start to resolve “the Double Cluster” into faint stars while the view in a small telescope will delight you. The 24″ shows several prominently orange stars.

Below Perseus is the bright Pleiades star cluster, also known as “The Seven Sisters”. Most people see six or seven tightly clustered stars but keen-eyed persons may glimpse eleven or more without optical aid. Binoculars will show the Pleiades’ full glory, revealing several chains of fainter stars.

Binoculars will easily show the cluster M34 about 40 percent of the way from Algol to Gamma Andromedae. After finding it, you should be able to see it with your unaided eye if you observe from dark country skies.

Finally, use your binoculars to sweep between the Perseus stars Alpha and Delta. You will discover a marvellous swarm of young luminous stars called the Alpha Persei Association.

By month-end you should see Venus becoming more prominent in early evening twilight. It will be a brilliant “Christmas Star”, joined by a crescent moon on December 23rd and Christmas Eve.

Minima of Algol Look for a decreasing light output of Algol two hours before or after the times given here. Sunday Nov 26 5:55 PM Friday Dec 8 5:11 AM * Monday Dec 11 2:01 AM Wednesday Dec 13 10:50 PM Saturday Dec 16 7:39 PM *between November 26th and December 8th the eclipses occur during daylight from this longitude.


ASTRONOMY AT THE MUSEUM by Orla Aaquist

In conjunction with the Fraser-Fort George Regional Museum, I am in the process of developing new physical science programs which address the Elementary Schools’ new curriculum. Among these are two astronomy programs, one for grade 6 and the other for grade 7.

The theme of the grade 6 program is Exploration of the Solar System. This program begins with a slide presentation which takes the students for a trip through the solar system. The slides are mostly images taken in the last two decades by unmanned satellites like the Voyager, Viking and Magellan satellites.

After the slide presentation, the students group into four teams. Each team is given a different picture of some solar system object, and they have to decide (as a group) what the object is. If they guess correctly, the team keeps the card; if they guess incorrectly, the card is given to another group during the next round. At the end of 10 minutes, the group with the most cards is declared the winner. This usually turns out to be quite a lively, competitive game. The images were cut from old Astronomy magazines, mounted on file cards and laminated.

When students visit the the museum, they like to explore the Exploration Gallery and the History Hall. We focus their exploration on astronomy by asking them to find objects which have one or more characteristics of some solar system object. Each team is given a sheet containing a list of solar system objects, and next to each object is a brief description of some of the objects’ main features followed by a blank. They are given 10 to 15 minutes to search the museum and fill in the blank with some museum artifact.

Afterwards, one spokesperson from each group reads out their list. For example, a cross cut of a tree’s trunk can represent Saturn because both have rings, and the tail of a fox can be likened to a comet because they both have fuzzy tails.

If time permits, the students also build a model solar system. Several spheres, of about the right proportion, represents the planets. Each team first decide what sphere should represent what planet. Then they lay the planets out on the floor using the Earth’s orbit as a scale. A long measuring tape with the correct scale marked on it is used to judge which team made the best placement.