Hamilton Amateur Astronomers December 1999 Volume 7 Issue 2 The Cassini Mission M uch has changed in 12,000 pounds. This includes the so that it can climb out of the Sun's the three hundred or Huygens probe, a separate deep gravitational well and reach so years since the Italian-French spacecraft that, once near Saturn, Saturn. astronomer Jean-Dominique Cassini will detach from Cassini and Cassini will also fly by Earth (1625-1712) gazed upon Saturn's parachute down to Titan, where it (August 1999) and Jupiter rings and was credited with will explore the giant moon's dense (December 2000) before finally discovering four of the planet's two atmosphere and record images of its having enough speed to carry it on dozen moons. But as NASA surface. to Saturn, where it is scheduled to launches the planetary probe named The Cassini spacecraft reflects arrive in July 2004. in his honor, it's testimony that -- multinational cooperation. The three centuries later -- some things European Space Agency (ESA) The mission's scientific goals are to remain the same, specifically built the Huygens Titan probe, investigate Saturn, its atmosphere, humankind's fascination with Saturn named for the Dutch mathematician its magnetic field, Titan, and several and our celestial neighbors. and astronomer Christian Huygens of the planet's small, icy moons. To achieve this, Cassini carries NASA's Cassini mission lifted off (1629-1695), who determined the eighteen instruments, six of them on on October 15, 1997, and will arrive shape of Saturn's rings and the Huygens Titan probe. The data at Saturn in June 2004, where it will discovered Titan. The Italian Space sent back from Cassini will help e m b a r k u p o n a f o u r-year Agency (ASI) provided Cassini's scientists on Earth better understand exploration of the planet, its giant high-gain antenna. Saturn's internal structure, the moon Titan, and several of its Cassini is taking the long way to structure and composition of its smaller moons. The Cassini Saturn, but for good reason. atmosphere, its wind patterns, and spacecraft is about two stories tall more. From that, scientists hope to and, with fuel, weighs more than After liftoff, Cassini will head in the get a better understanding of opposite direction of its Saturn's origin and evolution, and Saturn destination, toward perhaps our own. Venus. Using Venus' gravitational pull -- a sort of Scientists will examine Titan's slingshot effect called atmospheric composition and gravity-assist flyby -- Cassini chemistry, which may be similar to will swing around the planet a young Earth's. Titan has an Earth- in April 1998 and again in like, nitrogen-based atmosphere and June 1999, picking up speed a surface many believe features each time. These flybys will lakes of ethane and methane. The increase Cassini's speed Huygens probe will take images and relative to the Sun sufficiently (Continued on page 4) Chair's Report page 2 Ask Stella page 5 inside... Constellation of the Month page 3 Beginners' Page page 7 Links of the Month page 4 Calendar of Events page 8 Page 2 Chair's Report 'T 'T playing White Christmas in malls, is the end of the and another Mars probe goes fizzle. C a l e n d a r y e a r , If you are looking for stocking Christmas is almost upon us, and stuffers, the calendars are all gone EE vent Horizon is a publication of the Hamilton Amateur the change of the century is about to and the handbooks are on Astronomers (HAA). happen. All this ... and time for backorder, but we might be able to another Chair's report. find some more key chains. Instead The HAA is an amateur astronomy of a new telescope this year, my club dedicated to the promotion and Before we look forward, there are wife is hoping for a Vermont enjoyment of astronomy for people of some very important C a s t i n g s all ages and experience levels issues that should be woodstove and I brought forward. Over shall get a cord of The cost of the subscription is the past couple of wood. I can read included in the $15 individual or $20 months I have been S&T beside it if I family membership fee for the year. working some very am good. Event Horizon is published a long and hard hours and minimum of 10 times a year. this has put a definite I hope all people crimp in my style as who, in whatever HAA Council chair of the. To the way they choose Hon. Chair Jim Winger point that I have been to celebrate the Chair Grant Dixon unable to carry out my coming season, Second Chair Stewart Attlesey job a Chair with any have a healthy and Secretary Marg Walton degree of reasonability. warm time of it. Treasurer Barbara Wight The whole board has jumped in to Obs. Dir Bret Culver ensure a seamless running of the. A final gift for all of you is that as Editor Rosa Assalone The most notable person in this is the year draws to a close, the Membership Dir. Ev Rilett Stewart Attlesey. His yeoman's century turns over and a thousand- HAJA Coord Rosa Assalone like actions in running a smashing year mark is passed. Astronomers meeting last month has not gone all should know that it is next year Councillors unnoticed by me. So at this time I that is the turn of the Millennium Ann Tekatch would like to publicly thank the and not this year -- the true gift of Doug Black board in general and Stewart in intellectual arrogance (the ultimate John McCloy particular for their great help. Y2K bug) I pass on to you. Have a Rob Roy Happy New Year as well! Doug Welch Now onto another thank you: while Everett Cerns has been thanked by Grant Web Site Stewart Attlesey, the past Chair, for dixon@netaccess.on.ca http://amateurastronomy.org/ the terrific telescope he made for the HAJA kids, I would like to do the same. This not only because it's a wonderfully well-made scope but also because it has an air about it that screams out "children!". It is a fun scope and all we need now is a clear night with a bunch of kids and, KAZAM!, we will have magic. Thank you, Everett, for all your hard work. You know it is the festive season when the lights go up, they start Event Horizon - Hamilton Amateur Astronomers Page 3 Constellation of the Month - Orion by Margaret Walton Trapezium. The trapezium is the includes the Horsehead Nebula O centre of an intense, star forming (IC434). region. Two other fainter stars in the rion has been associated in Trapezium can also be viewed under M78(NGC2068). This is a bright, all ancient civilizations with good conditions. Sir William large reflection nebula containing 3 great heroes or warriors. In Greek Hershel began his observing career stars. mythology, he was the son of by viewing the Orion Nebula with a Neptune and a sea-nymph. He was reflecting telescope (made by NGC2112. This is an open cluster handsome, tall and strong. He was himself) in 1774. This is one of the of magnitude 8.4. It is a large, rich a great hunter who boasted he could most incredible objects in the sky. cluster containing about 50 stars and kill all living beasts. The goddess It can also be viewed through is visible through binoculars. Gaea was alarmed at this boast and binoculars. sent a scorpion to kill him. He was NGC2141. This is an open cluster saved by the healer Aesculopius M43 (NGC1982). This is part of of magnitude 9.4. It is a small, rich (Ophiuchus), who killed the the Great Orion Nebula. It is a cluster containing about 100 stars. scorpion and healed Orion. This is large, bright nebula just north of played out in the sky when Scorpius M43. NGC2194. This is an open cluster arises as Orion sinks. Ophiuchus of magnitude 8.5. It is a large, rich crushes the scorpion under him and NGC2022. Planetary Nebula. This cluster containing about 80 stars and then Orion rises. appears as a faint disk. It is can be seen with binoculars. described as a bright, small round The celestial equator runs through nebula of magnitude 11.6. Orion, making Orion visible from all places on the Earth except the NGC2024. Flame Nebula. This is Arctic and Antarctic regions. Orion an area of faint nebulosity culminates in mid-December. surrounding a star. It is visible in 6" or larger scopes. It is large and Stars Betelgeuse ­ This is a red supergiant about 300- 400x larger than our sun. Its magnitude is 0.5 and is about 425 light years away. The name translates as `Armpit of the Giant'. Rigel ­ This is a blue- white supergiant of magnitude 0.12 and is the 7th brightest star in the sky. It is about 1,000 light years away and has a fainter blue companion. Objects M42 (NGC1976) Great Orion Nebula. This is a very bright, large diffuse nebula illuminated by four stars known as the Event Horizon - Hamilton Amateur Astronomers Page 4 Callisto and her son Arcas Links of the Month afraid, and fled into the woods, not to see her son for The Links of the Month for many years. One day, when C December were inspired by the theme for our General Meeting's featured talk on Sir William favorit Arcas was a young man, he allisto was the decided to go hunting and e companion of the went into the woods where his Herschel by Jeff Collinson. g o d d e s s D i a n a . S h e mother Callisto, the bear, accompanied Diana on the The first page is a listing of the resided. Callisto saw her son, hunt and attended her at her "Herschel 400" complete with whom she had not seen for bath after the hunt. One day images of each object and a many years. Forgetting she printable observing sheet. The URL the god Jupiter caught a was a bear, she rushed is http://www.stud.ifi.uio.no/~mikkels/ glimpse of the beautiful forward to embrace him. h400.html. Herschel was the first Callisto and fell in love with person to discover infrared radiation Arcas only saw a bear rushing her. Knowing that Diana had so I have chosen the following web down on him. He lifted his warned Callisto of the site that is devoted to infrared bow and let fly an arrow to astronomy: http://www.ipac.caltech. deceitful ways of men and the mark. edu/Outreach/Edu/outreach.html . gods, Jupiter assumed the When I was looking for information guise of Diana. At the last moment Jupiter on the planet Uranus, which was discovered by Herschel of course, I intervened and cast Callisto In this disguise, Jupiter came across the Stardate Online and her son into the heavens seduced the beautiful Callisto. web site at http://stardate.utexas.edu/ as the constellations Ursa default.html. This looks like good Callisto succumbed to the Major, the Great Bear, and site to bookmark and if you follow beautiful seductive words of Bootes, the Bear Warden. the links they have a page about Jupiter, and in Jupiter's loving Uranus. Arcas is always standing next embrace, she conceived a child. When Jupiter's wife Juno saw this evidence of Jupiter's infidelity she became enraged, and changed Callisto into a bear. Callisto was ashamed and T he members of HAJA would like to thank Everett Cairns for spending a great deal of time and Cassini (continued) effort completing the telescope for HAJA use. It is a wonderful gift (Continued from page 1) and much appreciated by all HAJA gather data from Titan's surface, the spacecraft to within 110,000 members. hoping to discover whether or not miles of Saturn's center; others will lakes cover the moon. Scientists take it 2 million miles away. The next meeting of HAJA will be believe that Titan's surface may be Tuesday, December 14, 1999. The covered with the residue of a sticky, Most of the orbits will occur in, or following meeting will be Tuesday, brown organic rain. close to, Saturn's equatorial plane, January 18, 2000. HAJA - the where the planet's rings and many of junior astronomers, usually meets at For four years, Cassini will make its moons are located. Some orbits, McMaster University in the room about sixty orbits of varying sizes however, will take Cassini above or beside the planetarium, at 7pm. and orientations around Saturn. below that mark to get better views Some orbits will take 100 days, of the planet's poles. For more information on HAJA some less than 10. Some will bring contact Rosa Assalone at 540-8793. Event Horizon - Hamilton Amateur Astronomers Page 5 Ask Stella: The Life Cycles of Stars Ask Stella: The Life Cycles of Stars O person's life? I came up with smaller. The T-Tauri star gains ur question this month is these, but maybe mass because gas is still falling from an entire class of you can think of onto it, but it also ejects gas in curious kids -- Mrs. Jamison's d i f f e r e n t two gigantic jets. 6th grade science class at ones. Eugene A. Tighe in New Jersey, main sequence star to be exact. They write: *embryo - The star gets hot enough that *fetus hydrogen fusion can begin in We would like to know if you *baby the core (10 million degrees could possibly make an analogy *toddler Kelvin) of a star's life to the stages of *child human life to the life cycle of a red giant star. We are studying the birth *teenager - The star runs out of hydrogen of a star(nebula), protostar, *adult in the core so fusion stops. No developed stars, Supergiant --low *middle-aged fusion means no heat and no mass stars become a black woman/man heat means no more gas dwarf, or a massive star ending *old woman/man pressure. At this stage there's no in a black hole. Any ideas would longer anything to balance the be helpful--like is the protostar What about a star? In your inward pressure of gravity. The comparable to a toddler stage, question, you listed some of the star's core collapses and gets etc....Thank you for your stages: hotter. That makes the outer attention to this question. Mrs. layers of the star bulge outward Jamison's 6th grade science nebula until they cool down. class protostar developed star The cool outer layers go from And Stella, (ever one to put off (astronomers call yellow-white to red. doing a few calculations for the this the "main sake of wide -eyed kids) sequence" Think of a candle flame. The responds: phase) hottest part is blue, the second supergiant hottest part is yellow-white and Hi Guys, black dwarf the coolest (outermost) part is black hole orange or red. Although a red Wow, impressed that you're giant has a super-hot core, it's studying stars in the 6th grade. My list would be a little different. outer layers are cool. When I was that age, I thought Actually, I'd make two lists, one stars were just these little pointy for low mass-stars and one for helium flash things instead of gigantic nuclear high-mass stars. Mass is just the - The star's core gets hot enough furnaces that make up all the amount of matter (stuff) inside an to begin helium fusion. (100 elements in our bodies. Looks object. The idea of mass is million K) like I'm gonna have more similar to that of weight, but not competition for grant money exactly the same. It might help asyptotic giant branch (AGB) soon. you to think of those two ideas star as the same for now. - Helium fusion is happening in To answer your question, yes, I the core and hydrogen fusion is think you can compare a star's 1: Low mass stars happening in a shell around the life with that of a human being. core. Sometimes the star But the question of which stages nebula changes brightness wavers at are comparable is a difficult one, - The star-to-be collapses from a this stage, like a guttering candle because the stages of of a cold, dark cloud of gas. flame. When this happens, the person's life aren't the same star becomes an RR-Lyrae length as those of a star. protostar (T-Tauri stage) variable. However, I'll give it a try. - The ball of gas continues to collapse. It heats up as it gets black dwarf How many stages are there in a (Continued on page 6) Event Horizon - Hamilton Amateur Astronomers Page 6 The Life Cycles of Stars (Continued from page 5) all the elements heavier than and, or supergiant - The star runs out of helium. iron (like nickel, copper, silver, - Often adults change their job or Because it's only a little star, it gold, mercury, uranium, their ideas or their style of living can't get hot enough to use other plutonium) are made. when they're in their 40s or 50s elements as fuel, so it just sits and their children have left there and cools off. neutron star or black hole home. The bodies of women and - After the explosion the star men begin to change, just like becomes either a tiny, rapidly the body of a star changes when 2: Medium mass stars spinning neutron star (about the it goes from hydrogen to helium size of a city) or a mysterious fusion. This happens in different These start out in the same way black hole. Only the most ways for different people. as low-mass stars, But after they massive stars get to this stage. might have more than one red old age = black dwarf/white giant and AGB stage. And after Now, as far as comparing these dwarf/supernova/black hole that, something different stages to a human life, you can happens. have lots of fun. I would match - Old age is not the same for any up the stages in the following two people. Some find old age to planetary nebula way: be a very stable and happy time, - The star is getting old. It begins some don't. Some people to blow off its outer shell, embryo = nebula become brighter and more causing huge amounts of gas to - A nebula isn't really a star, just productive when they're old, but stream into space. like an embryo isn't really a other people believe their youth person, it's a potential person. was the best part of their lives. white dwarf The nebula is also warm and - After most of the gas has blown dark, like the inside of a womb. One place where this analogy away there is a tiny core left, really breaks down is with having about as big as the Earth (this is child/teenager = T-Tauri star children. Humans are able to very small for stars -- even the -T-Tauri stars are energetic and have children when they're quite Sun is a million times bigger than unpredictable. They change their young, but stars can't produce the Earth). No fusion is brightness in a matter of hours or other stars during their own happening any more. days. In the same way, young lifetimes. One generation of stars people often laugh or cry for contributes only a little bit to the reasons that adults find hard to formation of the next generation. 3: High mass stars understand. Anyway, I've really got to get The biggest, brightest stars also -T-Tauri stars are also hard to some research done now, but it have the shortest lifespans. In a keep an eye on because they're was fun answering your few millions or tens of millions of hidden by dark clouds. Kids also question. I hope you continue to years they go from nebula to have a way of disappearing on be curious about the stars. protostar to main sequence star. you. Or maybe you can't see But after that you can get them, but boy can you hear them! supergiant - This is the same as a red giant adult = main sequence star except bigger and brighter. -Main sequence stars are stable. Best Wishes, Supergiants can be red or blue. They've realized their potential Stella and have settled down to a life of supernova doing what stars do. This phase - When the star has a substantial is the longest of a star's life, just iron core, fusion is no longer as adulthood is the longest possible. The star ends its life in phase of a human life. a tremendous explosion where mid-life change = red giant phase/helium flash/AGB star/ Do you have a question that's keeping you up at night? Then Event Horizon - Hamilton Amateur Astronomers Page 7 Beginners' Page Finding Your Way t i m e y o u s e l e c t . Around The Sky - Planispheres are very Selecting The Sky Map useful for helping you f i g u r e o u t w h i c h That's Right For You. c o n s t e l l a t i o n s a r e W visible. They don't show which planets are up, hether you've nor are they helpful for bought your first i d e n t i f y i n g t h e telescope and need constellations. Because something to look at; or of their small size want to learn the (generally 4" to 8" in constellations; or just d i a m e t e r ) a n d t h e want to find out what r e s u l t i n g m a p The Magnitude that smudge is you see projection, planispheres in the sky at the show distorted views of Scale cottage; (or ALL of the the constellations. above!); you need a sky map or star chart as we To help you identify the by Ann Tekatch astronomers call them. c o n s t e l l a t i o n s , I recommend the monthly There are many star sky maps found in the charts available - which A c e n t r e o f S k y & stronomers measure one is right for you? Telescope, Astronomy or t h e r e l a t i v e Sky News magazines. brightness of stars Firstly, it helps to These are excellent for using a magnitude scale. recognize that each star finding constellations The brighter a star is, chart shows a different because they also show a the lower its magnitude. amount of the sky. horizon that offers a Obviously, a chart that scale against which you The brightest star in covers the entire sky can judge the relative the sky is Sirius found can only show the s i z e o f t h e in the constellation brightest of stars. constellation you are Canis Major (which is Otherwise it would be a trying to find. They located below the more confusing jumble. also show the location w e l l - k n o w n of any planets that constellation, Orion). The simplest star chart happen to be visible. This star is magnitude - is a planisphere. This These maps are good for 1.4. is a rotating disk with finding constellations a window that shows all from the city or other As a comparison, in the t h e c o n s t e l l a t i o n s light polluted areas city, the dimmest stars v i s i b l e f r o m your only, though. They only we can see are about latitude at the date and show the brightest of magnitude 4.0. Whereas, stars. If you are t h e d i m m e s t s t a r s observing from the visible to the naked eye country or a cottage/ under the darkest of campground where there s k i e s i s b e t w e e n i s l i t t l e o r n o magnitudes 6.0 and 7.0. artificial light, the sky will be much darker Each step in the scale and many more, fainter, means a difference of stars will be visible. You need a star chart (Continued on page 8) Event Horizon - Hamilton Amateur Astronomers Page 8 Beginners' Page (continued) (Continued from page 7) mid-sized telescope. that shows fainter s t a r s . F o r t h e s e If you're lucky enough observers, I recommend to own a large telescope Wil Tirion's Bright Star (10" +), you need Atlas. This atlas of serious help!! I use Sky star charts shows all A t l a s 2 0 0 0 a n d the stars visible to the supplement it with Did you naked eye under very U r a n o m e t r i a w h e n dark skies as well as observing with my 12.5" know the brighter deep sky r e f l e c t o r . that... objects (galaxies, star (Uranometria's charts clusters and nebulae) detail much smaller tha can be seen either areas of the sky, although they naked eye or with small enabling them to plot t e l e s c o p e s o r very dim stars and deep must have binoculars. The Bright sky objects.) witnessed Star Atlas can be used in the city with small If you have a gigantic them, the t e l e s c o p e s a n d telescope (18" +), you Egyptians binoculars because such can still use Sky Atlas i n s t r u m e n t s g a t h e r 2000 to locate star never enough light to allow f i e l d s i n y o u r recorded a you to see the fainter f i n d e r s c o p e , t h e n stars. Uranometria to close in single solar on the general area or lunar If you own a larger you're interested in. telescope (4" - 8" in After that, you'll need eclipse. aperture or diameter), to use one of the you'll need a star chart computer-based chart that shows even fainter generating programs that Rob Roy stars. Sky Atlas 2000 is are available. These a necessity! It shows programs make use of not only faint stars (to databases listing stars magnitude 9), but all to ridiculously dim the deep sky objects magnitudes like 20! that can be viewed in a Unfortunately, you'll CALENDAR OF EVENTS * Tuesday, December 14, 7pm HAJA - We will meet at McMaster University, in the Burke Science Building, room B148. For more information contact Rosa Assalone 540-8793 * January 7, 8, 28, 29 ~ 8pm BINBROOK OBSERVING NIGHTS - For confirmation or directions call Bret Culver 575-9492, Marg Walton 627-7361, Rob Roy 692-3245 * Friday, January 14, 2000 7:30pm HAA GENERAL MEETING - At the Spectator Building auditorium. * Tuesday, January 18, 2000 7pm HAJA - We will meet at McMaster University, in the Burke Science Building, room B148. For more information contact Rosa Assalone 540-8793 Event Horizon - Hamilton Amateur Astronomers Page 9 Event Horizon - Hamilton Amateur Astronomers Page 10 Event Horizon - Hamilton Amateur Astronomers