Hamilton Amateur Astronomers June 1997 Volume 4 Issue 8 Telescope Haute Couture hen you've been in Then, in the mid -'80s, their size, but their unobstructed astronomy for a few years, another 'scope design made a apertures and near colour-error-free it's hard not to look back at dramatic resurgence. The refractor, performance delivered image quality the way things have evolved. A case in long regarded as having wonderful most amateurs had never experienced imaging qualities, but expensive and before. The apo refractor's inherent "Some have observed that this cumbersome in larger (over 4" light efficiency meant that a 5" example growing, `new age' infatuation aperture) sizes, was revitalized by the could come surprisingly close in image with small, high performance advent of new and better glass types brightness to an average 8" SCT, but scopes is something akin to a that allowed manufacturers to offer with better contrast and cleaner looking `cult'." bigger apertures with better colour images. Still, very few people gave any correction, in shorter, more serious thought to using smaller (i.e. 70 point is telescope styles. Back in the manageable focal lengths. These to 90mm), well corrected instruments mid-'70s, when I first started getting "Apo" (short for apochromatic) for anything other than casual or "serious" about 'scopes, the popular refractors were still expensive for (Continued on page 3) choice for people considering a good, all-around instrument, was the medium to large Newtonian. Several companies The Orbiting Gourmet made these scopes, usually in the 6 to 12 inch size range, and they offered Once again, the summer is or sand excellent resolution and light grasp for nearly upon us. In a few generous dash' of ammonia a reasonable price. Unfortunately, weeks people will be dusting (Windex will do) Newtonians tended to be big and bulky, off those electric fans and thinking a tablespoon of dark corn syrup so it was no surprise that compact, about packing up the RV. "What about (maple syrup, honey, etc.) catadioptric scopes being offered by Alaska this year, honey? It's pretty cool a few drops of vinegar Celestron, Meade (and to a lesser this time of year." "Comet" brand cleanser (optional) extent, Criterion) gained in popularity with the coming of the '80s. It was To aid you in cooling off this large plastic mixing bowl possible to buy an 8" aperture, full summer, here are a couple of medium-sized garbage bag or mounted Schmidt-Cassegrain for the astronomical recipes that are sure to plastic liner same price as a far less portable 8" please. Creating a comet in your kitchen work gloves Newtonian. On top of this, the Schmidt is not only an excuse for playing with large mixing spoon or ladle was better suited for a wide range of neat materials, but will draw questions paper towels photographic applications. On the from youngsters like you wouldn't down -side, the SCT (Schmidt- believe. DIRECTIONS Cassegrain telescope) didn't quite have the image clarity of its hulking Dry Ice Comet 1. Line bowl with garbage bag. Newtonian cousin, but most users were 2. Add water and ammonia. willing to accept this in light of the 2 cups of water 3. Add dirt. many other benefits. 2 cups of crushed dry ice* 4. Add corn syrup and vinegar 3 heaping tablespoons of dirt and/ (Continued on page 5) Astrologic Puzzle page 3 Ask the "Expert" page 5 inside... Gateway to the Universe page 4 Summer's Finest Sights page 6 Averted Imagination page 4 Bargain Refractor page 8 KW Meeting page 4 July Night Skies page 9 Page 2 Editorial t's summer and that means bean shape once a year and drifts along lots of observing at Binbrook the Earth's orbit in a spiral which and at the various star repeats itself after 385 years. The parties. For those of you who missed closest this asteroid approaches the the HAA star party you can still make it earth in its orbit is 15 million to the North Bay event (details on page kilometres. The asteroid is somewhere vent Horizon is a publication 4) or Starfest. If you have never been to between 1 and 10 kilometres in of the Hamilton Amateur a star party before, you should at least diameter and is the only known Astronomers (HAA). try to go to Starfest even if you don't companion to the Earth other than the own a telescope. You can ask anyone Moon. The HAA is an amateur on the council for details about this astronomy club dedicated to the event. You can get far more information promotion and enjoyment of astronomy than I could possibly squeeze into this for people of all ages and experience One of the advantages of doing the small space by checking out the web levels editorial at the last minute is the pages at: opportunity to include late breaking http://www.asteroid.yorku.ca/companion The cost of the subscription is news. The news that I am referring to is included in the $15 individual or $20 the discovery that the near-Earth If I receive enough articles by the family membership fee for the year. asteroid 3753 (1986 TO) is a very July 25 deadline there will be a summer Event Horizon is published 10 times a unusual companion to the Earth. This issue of EH in time for Starfest. year. asteroid shares Earth's orbit around the Sun and its "horseshoe" shaped orbit is Stewart Attlesey HAA Council stable offering no danger of colliding attlesey@interlog.com Chair Doug Welch with us. Its orbit traces out a kidney Second Chair Grant Dixon Honorary Chair Jim Winger Secretary Patricia Baetsen Treasurer Barbara Wight Chair's Report Education Dir. Grant Dixon Obs. Dir Rob Roy t is a special pleasure to club in a number of ways, not the least Editor Stewart Attlesey write this report during the of which is the introduction of new Recorder Tracy Webb HAA Summer Star Party at ideas! Membership Dir Ann Tekatch the York Soaring Association field near I would like to thank all our members HAJA Coord Rosa Assalone Arthur, Ontario. True, the weather has and especially the Council members for been mediocre, but I always enjoy the keeping our group so active in the past Councillors fun and camaraderie of amateur year. Rose and Tracy have done a great Alan Shinn astronomers and I always enjoy getting job with HAJA. Rob has kept our Bill Tekatch to know people better. It is one of the calendars full of observing nights. Barb perks of being Chair! Ann Tekatch did has kept us afloat financially. Grant has Web Site a marvelous job of organizing the given us 1.5 zillion planetarium shows http://amateurastronomy.org/ HAASP and we thank her and will soon and has maintained a fantastic web forgive her for leaving at the first hint page. Stewart has routinely generated a of cloud! (Actually - it had been raining quality newsletter that is the envy of pretty hard...). other groups. Ann has maintained contact with all our existing and When we return to meetings in potential members. It has truly been a autumn, it will soon be time to elect a group effort! new Chair. I have enjoyed the position immensely, but it is clear to me that my Clear skies this summer - see time is now spread too thinly and the you at Starfest or in the fall! HAA is not getting the attention it deserves. Therefore, I reluctantly will Doug Welch not consider being nominated for Chair next year. This will be good for the Event Horizon - Hamilton Amateur Astronomers Page 3 Telescope Haute Couture ... (Continued from page 1) every person has different priorities, "beginner" purposes. It was really the there's no such thing as the "best Using five different star yearning for the tack-sharp imaging of telescope" or the "only real choice" for atlases, five HAA members were using the new apo refractors, but in a cheaper, everyone. On the other hand, it doesn't five different-sized scopes of five more portable form, that led to the hurt to think critically about the different colours to look at five manufacture, advertising, and ever process, look through as many different different increasing popularity of today's small types and brands of instruments as objects. Last names have been left out refractor and Maksutov market possible before buying and don't get to protect the innocent. segment. caught up in a "fad" (i.e. maybe I should buy it, 'cause everyone else is...). 1. Doug's telescope was pink. Some have observed that this One thing's for sure, though. If you growing, "new age" infatuation with buck the trend and shop for something 2. Stewart used a 4-inch refractor. small, high performance scopes is "un-cool" (like a Newtonian, SCT or something akin to a "cult". While that achromatic refractor), you'll be getting 3. The black scope was pointed at assessment is certainly contentious, it is the best deal ever. Just pick up some Albireo in Cygnus. true that small telescopes have gained a old back issues of Sky & Telescope, lot of respect in recent years. The check out the prices in the ads and then 4. To the left of the green scope was the "hottest" scope now on the market is the adjust for inflation. You'll quickly black one. Meads's ETX, 90mm Maksutov, which realize that it's never been a better time is currently back-ordered for up to 10 to buy a telescope! 5. Ann was observing the double- months. TeleVue's Ranger 70mm ED double in Lyra. refractor (along with its more expensive Clive Gibbons 70mm sibling, the Pronto) are huge 6. The owner of the 8-inch scope was sellers, as are just about every small, using a Cambridge Star Atlas. highly corrected refractor now on the market. It's a much different situation to 7. Norton's Star Atlas was being used at a decade ago, when I worked in a the white instrument. telescope shop. Then, customers who were looking for a "serious" telescope 8. M57 in Lyra, the Ring Nebula, was wouldn't consider anything smaller than being observed in the middle scope. a 4" refractor or a 6" Newtonian and often pined for an 8" or larger SCT. We 9. Bill was the first one on the left, next once stocked a beautiful Pentax 70mm to the gray telescope. semi-apo refractor on a solid equatorial mount, all priced at about $1300. It sat 10. Next to the 10-inch reflector, a for 3 years, unsold. "Sharp, but too Astrologic Mag-6 Star Atlas was being used. small", was everyone's opinion. Also available were very compact, quite Puzzle 11. The owner of Sky Atlas 2000 was sharp 4" SCT systems from Meade and star hopping from the double, a- Bausch &Lomb. They were well built, Herculis. inexpensive, but slow sellers. The e had a good turnout at a reason? "Nice, but too small", most recent star party, so I thought 12. The white telescope was next to the would say. that I would take a few notes 6-inch reflector. and write a short report for Event All this really illustrates is how Horizon. The only problem is that I 13. Rosa was using Uranometria. the marketplace's priorities can change, spilled hot chocolate all over the for whatever reasons. Smart advertising clipboard and can't read half of what I can account for some of the swings in wrote. There should be enough "telescope fashion", but it's more than information left to solve the problem. Rob Roy that. Sure, a big telescope will gather royrg@mcmail.cis.mcmaster.ca more light and show you more, but I've listed below all I can read, there's much to be said for extreme but I HAVE to know who was portability and razor sharp optics, too. observing M13 in Hercules and who A lot of factors need to be considered had the 3-inch refractor. Please help! when choosing a telescope, and because Complete set of Naglers for the correct answers! Event Horizon - Hamilton Amateur Astronomers Page 4 Gateway to the Universe e invite you to come and * The town of Powassan is located experience an astronomical about 30 km. south of North Bay, AVERTED adventure with fellow Ontario. stargazers under the dark sky of * Take highway 534 west from IMAGINATION- northern Ontario. The weekend is Powassan. relaxed, unhurried, and family oriented * Travel about 5 km. and then turn What's that? with plenty of opportunity for dialogue south on Alsace Rd. with other people who enjoy the * Follow the signs to Munro Park hat's when you've convinced wonders of the night sky. yourself you can see that galaxy/nebula in the Schedule eyepiece when nobody else sees Friday, July 4 Registration Form anything. 7:00 PM Bopp This. Guest speaker: YOU! Name___________________________ That's when you've convinced You are invited to bring your yourself you can see that galaxy/nebula slides, photos, and stories of the Address_________________________ in the camera viewfinder but it didn't great comet. appear on your photo. City____________________________ Saturday, July 5 When you observe what 11:00 AM Swap Shop. Province/ appears to be a faint globular cluster, At the picnic shelter tables. State____________________________ and after squinting at it for many 1:00 PM Tent Talks m i n u t e s a t h i g h p o w e r , y o u 5:00 PM Supper break Postal Code/ triumphantly announce, "I'm just 7:00 PM Tent talks Zip_____________________________ starting to resolve the outer stars...", only to be told that the object in the Speakers Phone___________________________ scope is actually an elliptical galaxy. (Clive Gibbons) * Steve Dodson Car License_____________________ Sudbury, Ontario Rob Roy Why We Do What We Do Fees * Wilf Meyer Weekend Registration Sudbury, Ontario $15 per person____________________ KW Meeting Northern Lights Over the North Pole Overnight Camping First 2 people n June 20, join the members * A Tale of Two Tiny Rocks $11.77 per person ________________ of the RASC - Kitchener -- the Lindy Meteor Each additional Waterloo Center for a $2.14 per person__________________ general meeting. * The Sudbury Meteor Impact Non-Campers Dr. Bob Dony will be * Antarctic Meteor Rock $2.00 per day ____________________ addressing us with a full multimedia presentation on digitally enhancing * Alan Ward Total ___________________ astro images (i.e.. how to properly use Sudbury Astronomy Club Registration Form To: all those neat programs we all own but Mirror Coatings North Bay Astronomy Club don't use well). We have room for as c/o Tom Ouellette many as can make it. * Jeff Collinson 221 Mulligan Street Sir William Herschel John Beingessner, North Bay, Ontario President RASC - Kitchener Waterloo P1A 3P4 If interested please copy and fill out the Center Registration Form. For further information, please contact: johnbein@golden.net How to Find Us Merlin Clayton (705) 472-1182 johnbein@bwheat.com Tom Ouellette (705) 474-7666 Call Ann Tekatch 905-575-5433 or E-mail: tdb@vianet.on.ca Stewart Attlesey 905-827-9105 for directions. Event Horizon - Hamilton Amateur Astronomers Page 5 The Orbiting Gourmet ... (Continued from page 1) nitrogen is only a quick-freeze agent. (which represent various organic Very little is left behind once the water Using an optical telescope our molecules). is frozen. Still, it's fascinating to poke at view of the Milky Way is restricted by 4a. Add Comet cleanser (which is the comet with a stick and explore its interstellar dust which absorbs the light meant to represent inorganic crusty, dirty surface. It's also good if from stars. Most of this dust is found in molecules). you don't have time to spend several the plane of our galaxy. Making 5. Stir. hours staring at a dirty snowball. observations at radio and infrared 6. Add dry ice (which represents wavelengths allows us to penetrate this methane ice) while stirring The dry ice comet, on the other dust Based on optical observations vigourously. (Handle with gloves.) hand, will produce the kinds of jets that alone, William Herschel, in 1785, 7. Continue to stir until the you see on a real comet and is good for concluded that we were near the centre mixture is half-frozen into a heavy hours of fun. Either way, making a of the galaxy. He based this conclusion slush. comet is a great opportunity for some on the fact that he was able to count 8. Lift out of bowl with plastic hands-on astronomy. So invite your about the same number of stars in any liner and mold into a snowball. friends. Dazzle those pesky neighbors. direction around the Milky Way. 9. Hold tightly until it has frozen Put your kids in awe of you forever and into that shape. make a comet. The idea that we were not 10. Unwrap and place in the sun. near the centre of the galaxy came Little jets of vapour will puff out from Denise Kaisler about mainly due to the efforts of the mottled surface of the comet kaisler@soback.kornet.nm.kr Harlow Shapley's investigations into nucleus, creating realistic jets. If it's a the distribution of globular clusters. cloudy day, a bright (200 W) lightbulb Dry Ice Comet Recipe by Jaymie Because of their brightness and the fact or heat lamp will do. Matthews that they are not confined to the plane * Dry ice (or frozen carbon dioxide) is matthews@astro.ubc.ca of the galaxy, where they would be the essential ingredient, which you can obscured by dust, globular clusters can get from chemical suppliers and ice be observed optically to very large cream stores. It's sold in blocks, so once distances. To determine the distribution you get some, you'll need a hammer to of globular clusters it is necessary to crush it. measure their distance as well as their position. One technique for this is to Liquid Nitrogen Comet measure the apparent brightness of RR Ask the Lyrae variable stars within the globular This is a quicker version of the clusters. Since RR Lyrae stars occurring above recipe. Instead of the two cups of in any particular cluster all have about dry ice, you'll need three cups of liquid "Expert" the same apparent magnitude they must nitrogen, which can also be bought also have about the same absolute cheaply from chemical suppliers. It can I have been reading about magnitude. By measuring their be stored in an ordinary thermos, but the size and shape of our apparent magnitudes in other clusters it take care to use it in a few hours, or it Milky Way galaxy and our is then possible to determine their will evaporate. Use the same solar system's location within it. I distance based on the dimming of light ingredients and directions as above and cannot understand how astronomers due to distance. Using this technique pour in the nitrogen, grabbing the can know how our galaxy looks, or Shapley found that globular clusters plastic liner and squeezing it at the where we are located in it. It would formed a spherical shell centered sides and top. Take care to wear proper seem to me to be similar to asking somewhere in the direction of clothing and use gloves. The someone to describe the external size Sagittarius at a distance of 25,000 to temperature of liquid nitrogen is and appearance of a house while that 30,000 light years. about - 70 deg. Celsius and will freeze person is sitting inside of the house in exposed skin cells in a second if you one of its rooms. How is this Recent near-infrared images spill some on yourself. determined? taken by the COBE satellite show our galaxy has the shape of a typical spiral The main advantage to this Brian Chire galaxy. (See page 10) comet is that it makes a glorious display A better analogy might be of hissing and boiling when the standing in a forest and describing its nitrogen is poured in. Anybody in the size and shape. The trees don't present a room is sure to be impressed. The solid wall in all directions offering us glimpses of trees beyond. Event Horizon - Hamilton Amateur Astronomers Page 6 Summer's Finest Sights he following descriptive list 41. NGC 6543, a bright blue-green ring, planetary, looks like a star in a 4-inch. is the second installment of a has an 11th-magnitude central star, just Colour is intense in larger scopes. 3-part series which first visible in a 3-inch. A fine object in an 46. M17, the Swan or Omega nebula, appeared in Sky and Telescope from 8-inch or larger scope. can been easily seen in a 3-inch. The Nov/1965 to Jan/1966. The authors, 42. 95 Herculis is a 6-second pair of Milky Way background is quite rich James Mullaney and Wallace McCall, bright stars, pale red and pale green in here. had spent five years carrying out a colour. 47. M22 is rated by the authors as the visual survey of every conceivable 43. M8, the Lagoon nebula, appears as finest globular cluster in the northern object down to -40 degrees declination. a nebulous patch traversed by a large hemisphere after M13. It is easily dark lane and a scattered open cluster to resolved to the center in a 10-inch. one side. A 3-inch shows all but the 48. Vega is a dazzling blue-white "Get out your star atlases dark lane, for which a larger scope is diamond. About 1 minute of arc to the and your Greek alphabet and needed. south lies a faint companion, difficult to plan your summer star 44. 70 Ophiuchi has a present see in less than a 6-inch. separation of 3 seconds. The colours, 49. Epsilon Lyrae, the famous double- yellow and red, are strong at 150x in double, is the finest multiple star in this Although the main instrument any size scope. list. Both close pairs, 2.3 and 2.6 was a 13-inch refractor, the 100 or so 45. NGC 6572, a small, bright, blue star clusters, red stars, nebulae, galaxies (Continued on page 7) and multiple stars in the list were examined in instruments ranging from Object/ Right 3-inch to 30-inch. They are listed in Constellation Ascension Declination Magnitude Type of Object increasing R.A., from 17 to 23 hours using Epoch 1950 co-ordinates which 33 Alpha Her 17:12 14.4 3, 5 Double star are only approximate for 1997. 34 Delta Her 17:13 24.9 3, 9 Double star Description of Objects 35 M92 Her 17:16 43.2 6 Globular cluster 33. Alpha Herculis consists of an intensely coloured orange and blue- 36 Rho Her 17:22 37.2 5, 5 Double star green pair, 4.5 seconds apart. 34. Delta Herculis, colours white and 37 Nu Dra 17:31 55.2 5, 5 Double star purple, is an optical 9-second pair. 35. M92 is a globular with a bright 38 M6 Sco 17:37 -32.2 5 Open cluster center. Often overlooked because of its neighbour, M13. Easily seen in a 3- 39 M7 Sco 17:51 -34.8 3 Open cluster inch. 36. Rho Herculis, a 4-second double, is 40 M23 Sgr 17:54 -19.0 7 Open cluster attractive even in small scopes. 37. Nu Draconis. A pair of perfectly 41 NGC 6543 Dra 17:59 66.6 9 Planetary nebula matched white stars of equal brightness separated by 62 seconds. 42 95 Her 17:59 21.6 5, 5 Double star 38. M6 is a large, bright cluster of scattered stars. This and the next two 43 M8 Sgr 18:02 -24.3 ? Diffuse nebula objects need a low-power, wide-field view of at least 0.5 degrees to be 44 70 Oph 18:03 02.5 4, 6 Double star appreciated. 39. M7, a large, very bright open 45 NGC 6572 Oph 18:10 06.8 10 Planetary nebula cluster, is easily resolved in a 3-inch at 45x. 46 M17 Sgr 18:18 -16.2 ? Diffuse nebula 40. M23 is a large, uniform, and fairly rich open cluster, striking in an 8/10- 47 M22 Sgr 18:33 -24.0 6 Globular cluster inch at 150x. 48 Alpha Lyr 18:35 38.7 0, 10? Double star 49 Epsilon Lyr 18:43 39.6 5, 5, 5, 6 Quadruple star Event Horizon - Hamilton Amateur Astronomers Page 7 Summer's Finest Sights ... (Continued from page 6) Object/ Right seconds apart, can just be resolved in a Constellation Ascension Declination Magnitude Type of Object 3-inch. 50. M11, the Wild Duck cluster, is the 50 M11 Sct 18:48 -06.3 6 Open cluster finest open cluster north of -40 degrees for large instruments, yet easily 51 M57 Lyr 18:52 33.0 9 Planetary nebula resolved in a 4-inch. Very rich and compact, it has a bright star near its 52 Theta Ser 18:54 04.1 4, 5 Double star center. 51. M57, the famous Ring nebula, rates 53 Beta Cyg 19:29 27.9 3, 5 Double star as the authors' finest planetary. Its central hole is seen at 100x in a 3-inch. 54 M55 Sgr 19:37 -31.0 6? Globular cluster The faint central star needs a large scope to be seen. 55 NGC 6818 Sgr 19:41 -14.3 10 Planetary nebula 52. Theta Serpentis is an easy pair of white stars, separated by 23 seconds. 56 Delta Cyg 19:43 45.0 3, 6 Double star 53. Alberio is a beautiful 35-second pair, orange and blue. These colours are 57 NGC 6826 Cyg 19:43 50.4 9 Planetary nebula much more vivid in smaller scopes. 54. M55 is a large, rich globular, but so 58 M27 Vul 19:57 22.6 8 Planetary nebula far south that it requires a first-class 59 Gamma Del 20:44 16.0 4, 5 Double star night for a good view. To be seen as more than a hazy patch needs a larger 60 NGC 7009 Aqr 21:01 -11.6 8 Planetary nebula scope. 55. NGC 6818 appears as a bright, 61 61 Cyg 21:05 38.5 6, 6 Double star uniform, blue disk in a 13-inch. In common with other planetaries, it is 62 M15 Peg 21:28 12.0 6 Globular cluster starlike in small scopes at low power. 56. Delta Cygni offers a close (2- 63 Beta Cep 21:28 70.4 3, 8 Double star second) binary which needs a 6-inch in good seeing to be split. The primary is 64 M2 Aqr 21:31 -01.0 6 Globular cluster white, the comp anion blue-white. 57. NGC 6826 is sometimes called the 65 Mu Cep 21:42 58.6 4-5 Red star "blinking planetary." It consists of a pale blue disk with an 11th magnitude 66 Zeta Aqr 22:26 -00.3 4, 5 Double star central star. Looking exactly at the star, the nebula disappears; while looking 67 Delta Cep 22:27 58.2 4, 8 Double star with averted vision causes the star to disappear in the nebulosity. Alternating 68 NGC 7662 And 23:24 42.2 9 Planetary nebula rapidly between averted and direct vision gives a blinking effect. This can 69 19 (TX) Psc 23:44 03.2 5 Red star been seen in a 6-inch at 150x. 58. M27, the Dumbbell nebula, is large seconds apart. binary. Both stars are white. and bright, pinched near the middle in 62. M15. This bright and very compact 67. Delta Cephei, a 41-second pair, is 4-inch at 40x. globular is not completely resolved in a easily split in a 3-inch. The colours are 59. Gamma Delphini, a 10-second pair, 13-inch refractor at 190x. pale orange and white. appears delicately coloured yellow and 63. Beta Cephei offers an unequal 14- 68. NGC 7662 is a small blue dot in a pale green. second double of blue-white stars. 6-inch and a bright blue perforated disk 60. NGC 7009, the Saturn nebula, is a 64. M2, a very rich swarm, appears as a with a 13-inch. very bright, blue-green, featureless hazy patch in a 3-inch. 69. 19 (TX) Piscium has a very red elliptical disk. The appendages that give 65. Mu Cephei, long-famed as colour, apparent in all apertures. rise to the name are not visible even in Herschel's garnet star, is a semi-regular, a 30-inch reflector. variable super giant. It is almost red in a Submitted by Rob Roy 61. 61 Cygni, a famous long-period 3-inch, deep orange in an 8-inch, and Observing Director binary star, has orange components 28 yellow-orange in a 13-inch. royrg@mcmail.cis.mcmaster.ca 66. Zeta Aquarii is a fine, 1.4-second Event Horizon - Hamilton Amateur Astronomers Page 8 A "BARGAIN" Compact Refractor ne of the most popular types of Next, hunt around for a telescope, nowadays, is the telephoto lens "telescope adapter". This Moth Story compact refractor. These accessory fits on the back of the portable li'l scopes can deliver telephoto and usually consists of a 90- surprisingly bright and sharp images, fit degree erecting prism and an eyepiece. he following recently easily on a photo tripod and travel The one I have has a wide-field Erfle appeared on the AAVSO virtually anywhere with a minimum of ocular (16.5mm focal length), so the discussion list: fuss. Apochromatic versions offer the magnification with my 500mm f/6.3 sharpest, most contrasty views, but they lens works out to about 30X, with a 2- aavso-discussion@physics.mcmaster.ca aren't cheap! The new Brandon 80mm degree true field. If you can't find a lists for $1295 (US) and even the "telescope adapter" or want to use a From: Tim Hager Teleview Ranger 70mm, which isn't wider range of eyepieces, you can cook To: Davesw5@aol.com apochromatic (but is better corrected up your own adapter by cobbling a T- Cc: aavso-discussion@physics. than an regular achromat) sells for ring to a suitable diagonal prism. mcmaster.ca about $600 (US). In the category of Subject: Re: Moth Invasion "conventional" achromats, several So, a little bit of hunting companies advertise compact scopes, around and a small dose of Hi Dave, most in the 80mm aperture f/5 size, improvisation can result in a compact selling for $250 to $300 US. These refractor that'll deliver bright, sharp You sound as though you feel you scopes are super-compact, but their images for less money than you might deserve combat pay! :-) Your story colour correction isn't good enough to have imagined. And, that "big ol' " reminds me of one that the late Walter a l l o w s h a r p v i e w s a t h i g h telephoto lens can take some darn nice Scott Houston told at one of our club magnifications (i.e. over 100X). Also, pictures, to boot! meetings once (or was it Stellafane?). consider that such compact achromats He said that they used to silver their will end up costing $400 to $500 Clive Gibbons own mirrors when he was young and Canadian and you might wonder if they would never observe the moon there's another solution. during the summer. This was because moths would fly into the moon's image If you're thinking about a reflected in the primary mirror and compact refractor for lower power smash themselves on the delicate silver observing, the answer might be closer coating. Apparently moth guts are not than you imagined. Take a trip to your good for silver coatings. friendly, neighborhood camera shop For Sale and check out what's available in big ....Tim (HTY) ol', used, telephoto lenses! Not "mirror lenses", but the long, unfashionable (in Tim Hager thager@pcnet. ausch and Lomb 8" Schmidt- the photographic sense), all-refractive com C a s s e g r a i n C r i t e r i o n lenses that were popular in the 1960's New Milford, CT reflector telescope with and early 70's. If you see a 400mm USA tripod and clock drive. I have adapters/ f/5.6 lens, consider that you're looking extension tube for astrophotography at a 71mm aperture, well corrected lens and 4 eyepieces - 30mm., 18mm., 50 system. A 500mm f/6.3 translates into mm. and 7mm., as well as the manuals. an 80mm aperture. Such elderly It was purchased about 8 years ago for "relics" of a bygone photographic era around $2,000. I'm asking $900 or best can be had for less than $200 and offer. sometimes less than $100, Canadian! They don't need to have fancy features, David Klooz, like autofocus, multicoatings, or 573 Glenridge Avenue automatic diaphragm. In fact, the St. Catharines, ON L2T 4C2 simpler, the better. Preset or Business Telephone: (905) 688-3762, completely manual diaphragm, T- Ext. 200 adaptable lenses are easiest to convert Home Telephone: (905) 934-3227 to telescopic use. Work Fax: (905) 682-3901 dklooz@regional.niagara.on.ca Event Horizon - Hamilton Amateur Astronomers Page 9 July Night Skies Event Horizon - Hamilton Amateur Astronomers Page 10 Letter to the Editor h e a r t i c l e , " Baffling Newtonians", by Rich Combs, in the May '97 issue of Event Horizon, raises some interesting points. While the whole question of whether a Newtonian really benefits from extensive baffling is -infrared. arguable, there is one major drawback to internal baffling that the author near neglects to mention. When constructing The Milky Way in a Newtonian, it is important to use a tube that is "oversized" with respect to the size of the primary mirror. This allows for air currents to flow along the Doug's Stuff Fer Sale inside of the tube as the scope cools down, without impinging significantly on the light path of the system. Bell and Howell LUMINA 10x50 $50 However, a baffle system, as described binoculars 8 degree field 300mm f/4.5 Telephoto, Canon mount by Mr. Combs, would significantly $175 $75 disrupt this necessary air flow in the (2) 8" blanks Keychains tube of the 'scope and result in "poor $65 each $6 each seeing" for an extended period of time. (3) 6" blanks (400 grit ground 2 sides) FAX/Phone line-splitter Therefore, such a baffle system could $45 each $40 significantly degrade the performance 6" Pyrex blank + ceramic tool Don't see what you'd like? Ask me! of a Newtonian under typical observing $75 conditions. 4 1/4" Pyrex blank Doug Welch $25 (905) 525-9140 x23186 (work) Clive Gibbons. 4" Optical flat (905) 524-0848 (home) $125 welch@physics.mcmaster.ca Metal detector $75 Super 8mm Canon camera CALENDAR OF EVENTS July 4,5 August 1,2 8:00PM BINBROOK OBSERVING SESSIONS - Proposed observing nights. For confirmation or directions call Rob Roy (692-3245) or Ann Tekatch (575-5433) Friday, June 27, 7:30 PM COUNCIL MEETING - Location to be announced. Call Doug at 525-9140 Extension 23186 if you are interested in attending. Friday, July 25, 11:59 PM EVENT HORIZON DEADLINE - Please submit your articles and pictures to Stewart Attlesey, attlesey@interlog.com or modem (905)827-9105 or snail mail to 1317 Mapleridge Cres., Oakville, L6M 2G8 July 4, 5 NORTH BAY STAR PARTY - See page 4 for details. August 7, 8, 9, 10 STARFEST - River Place. North of Mount Forest, Ontario. You cannot miss this one it is THE Canadian star party of the year. Thursday, September 4, 8:00 PM ROYAL ASTRONOMICAL SOCIETY OF CANADA Hamilton Centre - General Meeting - McMaster University Medical Building Room 1A6. Friday, September 12, 7:30 PM HAA GENERAL MEETING - at the Spectator Building auditorium. Speaker to be announced. Parking lot observing, weather permitting. Saturday, September 29, 8:00 PM COSMOLOGY DISCUSSION GROUP - Room B148 (next to the Planetarium) Burke Science Building, McMaster University. Topic will be "Introduction to Cosmo logy". For more information contact Bill Tekatch at 575-5433 o r tekatcba@mcmail.cis.mcmaster.ca Event Horizon - Hamilton Amateur Astronomers