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A S T R O N O T E S
Vo1. 12, No. 6 $2.00 a year June, 1973
Editor: Rolf Meier 77 Meadowlands Dr. W., K2G 2R9
Addresses: Mary Grey Dom. Observatory, 994-5474
Circulation: Ted Bean 399 Mcleod Street, K2P 1A5
In the February 1970 issue of the RASC Journal there appeared a new feature - the National Newsletter. Although officially established as such at the 1969 General Assembly, this type of bulletin had been suggested many years before. Tom Tothill, in particular, was instrumental in pushing for a publication to provide communication between Centers, and unattatched members who have no newsletter of their own. Even though a preferable solution would have been a completely separate newsletter, the center pages in the Journal provide a beginning.
At this time, contributions to the National Newsletter seem to be rather sparse. It rarely goes over the single green additional sheet. It is unlikely that the Editors would turn down any good material, so why dosent the Newsletter receive greater attention?
First of all, I think people regard it as rather remote.
The Journal itself deals largely with the professional aspects of astronomy, and many amateurs probably toss their Journal aside for reading when they can't find anything else to do. The Newsletter may never get read! Some readers of Astronotes may not even know of its existance as a means of communication with other amateurs across the country.
As a start in improving the importance of the National Newsletter, go back and read some back issues to see what the other Centers have been doing. If you feel really inspired in making your own contribution, do so, Here is the address where you send your submissions:
The Editor, Newsletter
100 Queen's Park
OBSERVERS GROUP MEETING - MAY 4 Cathy Hall
Ken Hewitt-White opened last month's meeting with several news articles, including our "get-well" message to Dr. Tom Legg, and the new Comet Kohoutek, to reach about 1st. mag. or better by December. This was Ken's last meeting as Chairman and Meteor Coordinator, as he will be leaving before June. Best of luck with the Vancouverites!
Slides were shown by a number of members - Mark Leenders on deep sky; Doug Welch on the Aurora of April 13/14; shots of the southern sky and a beautiful shot of M 42, courtesy of Dr. Fred Lossing; and some excellent views of a number of well known objects, by Rolf Meier.
Our graze coordinator, Karl Poirier, outlined plans to observe the grazing occultaion of the asteroid Vesta on May 5th, given clear weather. As well, he talked on various projects that could be carried out without a telescope - such as meteor work, satellite spotting, aurora observation, and recording of solar and lunar atmospheric phenomospheric phenomena. So, use your clear sky!
Next, Ken briefly mentioned the Eta Aquarid meteor shower,
and a much-needed apprentice session for new meteor observers.
Barry Matthews described the criteria for the "Certificate
of Observing Merit", offered a helpful hint to planetary enthusiasts - templates for planet shapes, and asked for photos of asteroid fields.
As a prelude to the General Assembly tours, Art Fraser
showed some very nice slides of the NRC Solar Complex, taken on a tour very kindly given by Dr. Vic Gaizauskas a number of months ago.
In closing, the regulations governing the use of our two
observing sites were read for the benefit of all who plan the use of them in the coming year.
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Copies of the Beginners' Package are available from Barry
Matthews or Cathy Hall for the sum of $1.00. See page 22 for addresses and phone numbers.
VARIABLES (9) Jon Buchanan
As I mentioned last time, we will now consider an interesting object located at the heart of M 1, the Crab Nebula. This object, a pulsar, is the remains of a cataclysmic explosion, a supernova, and is still in the process of dying.
Since their discovery and recognition in early 1968, quite a few have been found; over 50. At first thought to be dwarf stars that pulsed, periods in the order of .03 seconds discounted this as being physically impossible. Thoughts then turned to neutron stars, where matter is compressed to a point where the spaces between adjacent atoms is almost non-existant, and high magnetic fields where escaping electrons combined with the quickly rotating neutron star produces synchrotron radiation.
It is difficult to bring in all the theory on pulsars, and since all of them are emitting in the radio wavelengths, of what use are they to amateurs limited to optical instruments? Going back again to the Crab Pulsar, NP 0532, we find another interesting fact. This pulsar emits visible light also. With a period of .033 seconds, and a magnitude range of 18 for 90% of the time and 15 for the other 10% , it would appear as an 18th magnitude star. This requires large objectives, for amateurs, and possibly a "trick" mechanism, a stroboscope, to permit observations.
There are still attempts being made to find other optical pulsars, but such observations are beyond the scope of most amateurs.
With this we seem to have come close to the end of variable stars. In fact, we have reached the end of "variable stars".
We cannot stop here, for surely there must be something else out there that falls into the realm of variable star observations. Indeed there is. For now we can consider quasars.
Quasars, a name some scientists wish didn't exist. For it is a newcomer to modern astronomy. But unlike the pulsar, which readily fits into the scheme of things with a little bending, quasars threaten to break the system. These objects, if present theories are to be believed, are at the edges of our universe and emit tremendous amounts of energy. Or, they may be closer, and gravitational effects cause the high red shiftsobserved in all of them. Of course the book is far from closed on these objects, and observations are still needed.
Sample surveys of small regions and extrapolation of the results to the rest of the universe, indicate about 15,000 to 20,000 quasars are brighter that 18th. magnitude, and that the number skyrockets as you go down. Of these, only one in three hundred is a prominent radio source, others being optical. What is interesting to an observer is that quasars do vary in brightness.
Due to this fact, plus the availability of the 16-inch
telescope to a number of people who were interested, and the encouragement of others, a project was undertaken to observe quasars. Starting last year, around January, a number of people observed OJ 287. Intrigued by its unexpected behaviour, they continued to observe short-term variations over 30-second periods, drops of 0.5 magnitudes in 10 seconds and rises of same in 20 seconds. Long-term steady periods were also observed in those early days. Then the quasar sarted to settle down, concurring with the information received from professionals who were studying OJ 287.
This year, of the six runs done, about four hundred observations, OJ 287 appears to have quieted down even more, but still showing a slight fluctuation in the order of half-minutes still. These short-term effects, thought to be observer problems last year, have been observed by photometer in another object, BL Lacertae. An excellent write-up of these objects is in the April 1973 issue of Sky and Telescope. Longer variations in periods of days are also present, though not observed by us yet due to intermittent observations.
Aside from OJ 287, another quasar has been observed in the hopes of detecting similar phenomena optically - 3C 273. The brightest quasar, at about 12th. magnitude, has not shown such a rapid variation. This restored somewhat the faith of the observers in believing what they see.
Again it would take a book to explain properly what quasars are, or rather what is known about them As such, I have very lightly touched on them and have mentioned some of the work being done by a few of the more active members.
I am far from being an expert on variables and any half decent astronomy book will contain about as much, if not more than these articles have. The only thing I can say, now that the END is here, is to encourage you to try variable star observing. It is interesting in its own right, and the knowledge gained will help you in other areas of astronomy.
Partial reproduction, page 225, April 1973 issue of Sky
and Telescope. 100-inch Mount Wilson reflector, photoelectric light curve, each dot being a ten-second observation.
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A recent IAU Circular states that a period of 39 minutes has been found for the quasar OJ 287. Over the last year, our observations with the 16-inch indicate a similar period, about 30 minutes. However, they state a magnitude for the quasar of 18.4 visually, whereas we can quite surely say it was never fainter than 14th. magnitude or so. What seems to be the discrepency? A printing error perhaps?
SUMMER PROJECT Doug Beaton
Just a short note to mention that Rolf Meier and myself are hoping to make extensive tests of various films to determine their qualities in relation to astronomical photography. We have chosen eight different Black & White films from Kodak, Ilford, and Agfa, as well as eight commonly used developers. By interchanging developers, developing temperatures, times, dilutions, and procedures, we hope we can find a film which acheives maximum speed with minimal grain. Over a much longer period of time we will also compare printing papers and their developers. A full report will be presented in the fall.
Attention all Photographers :
In the past few meetings I have talked to many people who were just thinking of developing and printing their own pictures, and to those who make a living of it. What I would like to do is make a plea to all those amateur and professional photographers in the group, to please phone me and let me know just what you own in the way of darkroom facilities. I hope that if there is enough interest from our group then we can prepare serious, in-depth presentations on the subject in the fall.
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As New Member Coordinator, Barry Matthews has begun to
hear from various observers on what they are doing, via the observer check-off list:
Jules Meunier - Lunar photography, aurora, deep sky
Tony Mason- Tony hates the cold but will be chasing you older observers pretty soon.
Rob McCallum - Deep sky, comet hunting, planetary, variables.
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Dont forget these two programs for the 'Certificate of
Observers Merit": 1) Amateur Observers Log Book, and 2) Observers Messier List
See the April issue of Astronotes for details.
17° 10' W.LONG. 19° 52' N. LAT.. 6.1 MIN. DURATION Ken Hewitt-White
The first set of figures above show the latitude and longitude of a point in the North Atlantic Ocean, some thirty miles off the coast of Mauritania, West Africa, and are a good reason not to see an eclipse. (because its too far away, dummy!) The second set of figures expresses the duration in minutes of the totality of a particular eclipse, one of the longest of the past 1400 years, and are a good reason to go to an eclipse. As it turns out, the two sets of figures are related to the same event coming up on June 30 so that they just nicely cancel each other out. Silliness then takes over as the prime motive for the four people from the Observers Group that are cruising, driving, training, planing, and hitchiking over 7000 miles to see an eclipse of the sun.
The four who hope to stun the September meeting of the
Observers Group with awesome colour pictures of this ridiculous moon-shadow trick are each getting to the eclipse site in unique ways:
Rob Dick is taking an Air Canada charter flight to England
on June 19. In Liverpool he will set sail on the fabulous, floating wondertub, the "Monte Umbe". For 16 days Rob will wine and dine in luxurious comfort on this passanger-cargo ship. Presumably hell load flour and sleep with crated bananas, too. Rob is undecided as to whether hell watch the eclipse fromm the sea and get seasick or go ashore at Port Etienne and risk a Martian-like duststorm blowing off the Sahara. In any case Rob will bring his 8-inch, whose tube he hopes will double as a suitcase. Just for laughs, he is bringing two cameras too; the extra one in case he has to make a deal with the natives later on.
Cathy Hall, being the classy type, will motor down to
New York City and board the modest but serviceable P and O line Canberra. Although only 18Œ times larger than Robs boat, it boasts beds with every stateroom and a room for every booked customer. The Canberra will attempt a "dramatic rendezvous with the sun" (while the Monte Umbe promises only a "jolly good run at it") some 4583œ- miles east of New York, narrowly missing, no doubt, head-on collision with any of the other 750 similar craft in the same area. Cathy has been practising with her new camera and borrowed 5-inch telescope for months and not just on the sun but on the night sky too. The Canberra will park in Dakar Senegal - lat. 12° 30' N - overnight where enthusiasts can marvel at southern sights never before seen (native girls) and where the more experienced observers can take the best photos of M 31 yet.
Yours truly, the QS kid, will leave from Montreal on May 28 via youth standby DC-8 service to Heathrow. (you may receive Astronotes June 1; I may still be standing by) From there I will visit relatives in Liverpool and warn the local yard workers that Rob is coming. I hope to deposit myself in Joderell Bank, set Stonehenge, and then wander all over Europe on 4th class rail (you ride in the caboose) and end up in Marseille or jail on June 23. From there, I take a boat to my destination. The MS Massalia, something less than the Canberra but still more than a lifeboat of bananas, will cruise via Tenniferie in the Canary Islands to the same general area as the two aforementioned ships. I will be taking with me my 4œ" RFT complete with 10 x 40 finder and 2.4-inch guidescope in case the captain needs help in finding the spot.
Allen Miller, who didn't escape the Canadian cold and make
it to Spain will leave after all on June 16th and escape the heat by flying to England like the rest of us. Allen will travel to wherever they'll take him in, and ultimately wind up in Ca sablanca, Mo rocco on June 26th. Hell come on board the Massalia there and head straight for cabin 5004, located conveniently equidistant from the bar and the WC. Should Allen fail to appear by 4 pm on June 26th, I shall lean over the railing (a familiar pose by then) and search frantically through my finderscope for a scrawny red-haired Canadian who was, no doubt, forced to walk all the way from Gibralter in the 110-degree heat after he called some French-speaking, Spanish-Morroccan Arabic bus driver a silly name. Allen hopes to bring his 8-inch Schmidt-Cassegrain which, when aluminized, will weigh exactly 43Ÿ pounds. This leaves room (remembering the 44 pound baggage limit on planes) for all the basic necessities of midnight travel, except for his wallet which would no doubt be lifted as soon as he entered Spain anyway. Fortunately Allen may not have to worry about the weight because unfortunately the flood waters of the Jock River have crept into the telescope making machine shop of Karl Poirier where Allen currently has his tent set up. Allen may then only bring his movie camera and 37 packages of colour film, all of which will be wasted on the buses in London, filming pretty girls.
There you have it. The complete itinerary of possibly the
most challenging trek ever attempted by the (sillier) members of our Observers Group. None of us are afraid of lugging telescope equipment all over the place in foreign lands. Our main problem is getting the stuff past the security chaps at Uplands airport.
Incidentally, we're not the only nutty ones. Our friends from across the boarder in beautiful BC, three of them, are going too. They will be meeting Al and me in a pre-selected, sleezy Casablanca hotel bar. A special secret plan to snatch the eclipse right from under Murphy's nose will be revealed over cooling drinks and under an ineffective, slowly rotating fan.
Humphrey Bogart would be pleased.
We wish these people, especially Allen, clear skies during this eclipse. The pictures they bring back had better be good.
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JUPITER'S SATELLITES IN 1973 Rolf Meier
This year will provide a unique opportunity for amateur and
professional astronomers to witness the four large moons of Jupiter eclipse and occult one another.
Such occasions are rare, because it means that the Sun, Earth, Jupiter, and the Jovian Satellites must all lie on nearly the same plane. This occurs every 5.9 years (twice in Jupiter's year) for a period of three to six months. Previously, in 1967 and 1961, Jupiter was too near conjunction during these periods for the events to be well-observed from Earth. This year, however, the majority of the events occur between June and December, with opposition occuring on July 30.
The value of observing these phenomena is greater when complex equipment is involved. With accurate light curves of one satellite eclipsing another, it may be possible to derive a map of the satellites' surfaces. This would require a photometer and recording equipment connected to the telescope, and a computer to analyse the resuts, but it is one of the more ambitious projects planned. For amateurs, the phenomena should be interesting sights, and accurate timings and descriptions can be useful.
What is to be seen during a mutual eclipse or occultation is fascinating indeed. One satellite approaching another first eclipses the other, darkening it completely or partially. As it moves on, it may merge with it, close enough to completely occult it, or to make it seem like a single large moon.
A foreshadowing of these mutual phenomena was observed on
the night of May 6/7, 1973, and was seen by several people at North Mountain Observatory. The superficial appearance was as though two satellites only were visible:
A closer inspection when Jupiter rose higher above the horizon was made at about 4 am DST. When some movement of the satellites with respect to each other had taken place, it was discovered that all four were indeed visible but that three of them had appeared as one:
The satellites, once they were resolved, were seen to be
separating, so who knows how close the three may have been earlier! If anybody else saw this event, tell us about it.
Predictions of the mutual phenomena of Jupiters satellites
can be found in the BAA Handbook, or the February 1973 issue of Sky and Telescope. There are discrepancies of up to 30 minutes between the two sets of predictions, so watch out.
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Presumably Stellafane will be held again this year, most
likely on August 4th, although we have not heard from them yet. It takes place near the prosperous town of Springfield, Vermont. The Ottawa Center usually has a good showing, so all you telescope makers get busy and create a telescope that will marvel the judges! Prizes are awarded for the best telescope in a certain category, as well as for optical performance.
BARNARD'S STAR by Doug Welch & Doug Somers
With the coming of summer, Ophiuchus is becoming much more prominent, and within its boundaries lies a much publicised, but rarely looked-at star. It is Barnard's Star, the star with the greatest known proper motion of any star.
Barnard's Star is a 9.5 magnitude object with an interesting aspect. This star has a movement among the stars of about 10.2 second of arc per year. We have looked through numerous books and charts to draw up the map opposite. For those of you who photograph through the 16-inch, two photos three months apart should show the movement. For comparison, a few key stars have been lettered.
Barnard's Star can be seen with a 2.4-inch telescope. 66 Ophiuchi is a flare star. Any photos should be compared to see if such a flare has happenned. We would like a copy of any photographs. Good Hunting!
star mag RA Dec.
B 9.0 17h 55m 15.355s 4° 26 38.94" N
C 9.1 17 53 33.115 4 32 29.22
D 8.8 17 53 1.238 4 13 49.25
E 8.2 17 54 18.502 4 22 56.52
66 4.8 17 57 47.101 4 22 11.61
A fascinating project, indeed, that this could be with the 16-inch. If done carefuly, analysis of the star's motion may reveal the wobbles that are causing astronomers to speculate that this star has several unseen components, which are probably planets with masses a few times that of Jupiter.
DRAWING AT THE TELESCOPE Barry Matthews
Observers should always record what they see through a telescope by making a sketch. Granted, you willnot record the splendors of the universe as seen photographically by Palomar or Kitt Peak, but to take advantage of the fleeting periods of good seeing that can only be recognized visually, sketching is the answer. The drawing or sketch does not have to be a work of art but should be a clear, objective reproduction of what the observer sees. The cold of an Ottawa winter is a difficult factor to contend with. (drawings must be completed quickly but accurately - thus defeating the cold and combating the fast rotation of some of the members of our solar system).
If all the celestial observers were lumped together, the
one question they would have in common is what orientation have they when looking through an astronomical telescope. Remember that the astronomical telescope inverts the image north appears at the bottom and south at the top. Left is west and right is east. When recording astronomical events you should continue this procedure - draw it as it is seen in the scope. Another way is to adopt the ALPO practice of using "P" for preceding, and "F" for following.
For any type of record of events the observer should aquire a set of blanks in the form of a stencil. Clip this outline to a board and use a pencil and a soft erasor to start. In order to build up a sketch of a planet or lunar object you start off with the most evident feature and work to the limit of resolution of the scope. It is not a good habit to switch back and forth between low and high power. You should begin with a medium power (100 x to 150 x), and then to high power (150 x plus). When the rotation of a planet is rapid it is a good idea to start at the west limb over which details disappear in the course of the planet's rotation. These drawings or sketches should take no longer than 10 to 15 minutes to complete; then start others at intervals of 30 minutes to one hour.
When the observer is especially keen-sighted, and the seeing is exceptional, he may be able to add some colour. To do this, use good quality coloured pencils with the proper hue and delicate shading visible to the observer.
We will leave the planets for awhile end go on to our nearest neighbour, the moon. Possibly there is too muchscope making it difficult for the beginner to know where to start. Once this obstacle has been surmounted, the easiest forms for the beginners are the "line drawings". (this being an outline showing the main features) With lunar drawings the important thing to remember is to capture prevailing lighting conditions on the surface. The lunar landscape constantly changes appearance due to the change in lighting.
It has long been known that there are very dramatic differences between lunar or planetary phototgraphs and visual observations. This is partially due to the fact that photographic emulsions and the eye of the observer are sensitive to different spectral intensity ranges.
Notes to the observer:
1) Visual observation still fulfills a useful function. 2) Surface details revealed by photographs can be used as a basis for visual observations.
3) Observers should use both methods to complement one another.
References: ALPO - Lunar and Planetary Observing Booklet RASC - Beginners' Package, Ottawa Center
G. Roth - Handbook for Planet Observers
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CENTER MEETING, MAY 10
At the May 10 Ottawa Center meeting, a film about the Crab Nebula was shown. The story of how astronomers over the lest nine centuries have investigated every detail of this very interesting object was dramatically depicted. From its first sighting by Chinese astronomers in 1054 as a supernova, to present-day observations of the pulsar buried within it, this object has answered many questions on the evolution of stars, and raised many new ones. A discussion of the film followed, led by Arthur Covington.
A NEW CANADIAN TELESCOPE IN HAWAII
Actually, the cost will be shared by Canada and France, who will also share observing time with Hawaii. It will be located at an altitude of 14,000 feet on top of Kauna Koa mountain, where clear skies and good observing conditions prevail. The 144-inch France-owned blank will be finished in Victoria, B.C.
A. STATISTICAL APPROACH TO PLANETARY PHOTOGRAPHY Edward ter Heijden
Planetary photography requires infinite patience because
turbulence and vibration seem to be undefeatable enemies. To the amateur it seems that a good picture is obtained only once in a while. Why is the photographic capability of a telescope so inferior to its visual capability?
The answer to this question may be found if we examine
the amateur astronomer's choice of equipment. Almost invariably he will choose a 35 mm single lens reflex camera for planetary work because of its ease in focussing and keeping the object in view. What he forgets is that these cameras come with a built-in vibrator known as a reflex mirror and a focal plane shutter. These two devices give the telescope an effective kick every time an exposure is attempted. The 35 mm camera also has a frame size which is much too large. Typical amateur photographs of planets are not much larger than about 2 mm in diameter which results in more that 99.5 % of the film being wasted. By far the worst feature of the 35 mm camera is its small film capacity of 36 shots. If one considers that for an 8-inch telescope a typical planet exposure time is of the order of œ to 1 second, and that the "rock steady" seeing needed to prevent blurring rarely occurs for a duration this long, the chance of getting one good picture out of 36 is very slim indeed.
This last statement can be stated with very simple mathematics if we use the concept of probability. The probability of getting a good picture P equals the probability of there being good seeing S times the number of pictures taken n.
P = nS
Perfect seeing is defined as S = 1, whereas S = 0 means
the worst possible seeing. Some wise guy, up on his probability theory will no doubt point out that it is possible for P to be greater than 1. However, we shall take P to really mean the number of good pictures we end up with after taking n pictures. Generally speaking, S depends on exposure time, in that S increases in size when the exposure time is shortened. Evaluating S, however, is not the purpose of this article and its inclusion is only to illustrate a point.
Exercise: You are attempting to photograph Jupiter through a telescope using a 35 mm camera and an exposure time of one second. Due to atmospheric turbulence there is a "one in one thousand chance of getting the required seeing during an exposure this long; if all 35 pictures are taken, what is the probability in percent that one of them will be good? How many pictures should you take to get a good one?
Since atmospheric turbulence and vibration can be considered random phenomena, it is obvious from the previous exercise that a low-brow statistical approach to planetary photography should yield quite fancy results. What is needed is a camera that can take more than a thousand pictures consecutively and do it on a small, economical film size. A movie camera fits this description exactly, although the exposure time per frame is far too small for planetary work.
Considering amateur budgets, movie cameras, either 8 or
16 mm are too expensive and poorly constructed to modify to a slower rate. A modification of this type means removing parts and drilling holes. One camera which I recommend because of its excellent construction and price is a war surplus 16 mm camera. This type of camera was successfuly modified by myself and it may be purchased for $7.95 from J.J. Glass Co., 1524 South Main St., Los Angeles, California. After paying for freight and Canadian customs the total price came to $12. Empty re-usable film cartridges with a capacity of 50 feet may be obtained from Freestyle Gales Co., 1429 North Western Ave., Hollywood, California at 6 for $6.98. Standard 16 mm double perforated film can be used in these cartridges.
Camera modifications will not be given in detail, but it
consists mainly in removing the motor, some surplus gears which were used as a delaying mechanism, drilling a hole in the camera side for a motor shaft which in turn connects to a small electric motor of about 2 seconds per revolution. (or whatever is desired) Since the original camera had three speeds so will the modified camera. These speeds will be 1, 2, and 1 seconds per frame. The actual exposure times will be 2, 1, an œ seconds per frame because the shutter is of the rotating type and is only open half the time. The lens of the camera was unbolted and replaced with a 1Œ-inch outside diameter tube which fits into the telescope holder.
Since this camera does not have a through the lens" viewing capacity a film cartridge was modified by glueinga piece of ground glass where the film normally fits and drilling a hole in the opposite end. This hole is necessary to see the ground glass when the cartridge is in the camera. This system allowed for easy focussing and collimation of the necessary guidescope with the camera mounted in the eyepiece holder. A guidescope of about 50 power must be used to keep the camera on target.
Even the very first test made with this type of camera
showed superior results. In 500 pictures taken one evening of Saturn with an 8-inch reflector at f/30 at œ second on ASA 200 film, one frame was found that clearly resolved Cassinnis division. This feature requires a resolving power of at least 2 seconds of arc to be visible. Photographic detail this fine is quite rare in an 8-inch telescope. Examination of 500 pictures to get the best one entails a lot of work, but at least this method ensures that a good picture will be there.
Exercise: Construct a camera as shown in this article to resolve Encke's division in the rings of Saturn. When you succeed, try to resolve detail on the Martian pole caps.
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SAGITTARIUS Rob Dick
"Sagittarius seems to hold captive within her bounds more
outstanding Deep Sky Wonders than any other constellation."
from "A Midsummer-Nights Dream" by Miller, Hewitt-White
Much of the summer southern sky will be dominated by the constellation Sagittarius (The Archer), which is centered on the 19-hour meridian.
Sagittarius is known for containing the center of our galaxy (about 4° off from the "spout" of the "tea pot"). Since you are looking along the plane of the galaxy you will see many star clusters, some of the most interesting being the open clusters which under low power shimmer like diamonds. A few of these clusters will hold the most experienced observer in awe.
M 8 (6523; RA 17h 51m; Dec 17° 01 S) is 1 x œ degree,
shining at 6th magnitude. It is nicknamed the "Lagoon Nebula" which includes this cluster. Distance? about 2500 l.y.
M 18 (6613; RA 18h 17m; Dec 17° 09' S) is about .2 degree
across. About 12 stars are seen at the distance of 6000 l.y.
Next cluster here is M 21 (6531; RA 18h 11m; Dec 22°30S).
Its 7th mag. and a close neighbour of the "Trifid Nebula", M 20. 1/5th degree across at 3000 l.y. gives it moderate size.
M 23 (6494; RA 17h 54m; Dec 19° 01 S) is 4500 l.y. distant at 7th mag. I t ' s rather large at 25' of arc, corresponding to 30 l.y. in real diameter.
Finally M 25, also known as IC 4725, is at RA 18h 29m,
Dec 19° 17' S. Its a bright cluster at 5th mag. It is the closest of this set at 2000 l.y. Angular diameter, 40'.
All of these objects are close to us; no farther than 6000 l.y. The interstellar dust in the arms of the galaxy obscures more distant clusters. These objects may be glimpsed even with 2.4-inch refractor, though it may take a sky darker than that found at the city center! While you're at it, look at the nebulae and globulars here, not missing M 22.
Until September, I hope you will have good observing under bugless skies.
CLOUDED OUT a review by Barry Matthews
What Star Is That? by Peter Lancaster Brown
Mr. Brown has treated a much aired theme in his recent book in much the same manner as authors before him. However, to give credit where credit is due, the much worn subject is further hindered by some very obvious errors, such as "each of the four principal moons of Jupiter 'is as large as the Earth'"! Statements such as this are followed up with dangerous advice on sweeping to locate Venus and Mercury under bright sunlight with binoculars. This advice is given without the slightest warning for the beginner to stay clear of the sun.
The slides accompanying this book are of good quality but
are not what the amateur would see. One saving grace for this volume is the 75 variable star charts for the prospective variable star observer. When you are clouded out, take out this new volume of our library. Take it with a grain of salt and watch out for the obvious pitfalls.
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MURPHY'S COROLLORIES ON GRAZING OCCULTATIONS
2.1 Elevation of the sun = Elevation of the moon - 18°.
2.2 Observers in key positions will watch the wrong limb of the moon.
2.3 The strength of tape recorder batteries is inversely proportional to the strength of CHU receiver batteries.
2.4 The magnitude of the star will be proportional to air temperature. unless...
2.5 The magnitude of the star is inversely proportional to the distance from home, unless...
2.6 The magnitude of the star is proportional to the fraction of the moon illuminated by the sun.
2.7 The best locations for grazes are Siberia, Antarctica, and New Zealand.
2.8 When the above-mentioned conditions are NOT met, the event will be clouded out.
2.9 After the attempted graze, the heaviest vehicle will get stuck in the mud, snow, ditch, etc.
2.10 All participants will swear never to take part in another graze.
NEW METEOR COORDINATOR Chris Martin
Once again the Observers Group loses one of its finest members. First Ton Tothill, and now Ken Hewitt-White, have looked west (young men?), joining the ranks of the Vancouver Center. Actually, Ken won't be heading out that way until after his long-awaited appointment with the sun, somewhere off the coast of Africa. Early departure (May 28) necessitates the search for a new meteor coordinator.
After much consideration and consultation, Ken and I
decided that the only possibility was me. (But of course!) In reality though, many of the older members would not be able to take this position because of pre-arranged summer plans.
My own plans include an active summer program, especially the initiation of new blood into the meteor group. As for the increasing quality of the meteor program, I would like to maintain correspondence and start new communications with other centers.
For those interested in meteor observing during the summer, or those who would like further information on the present program, they may contact me at:
242 Powell Avenue Ottawa, Ontario K1S 2A5
Subject to group approval at the June meeting.
BRIGHT, NEW, COMET KOHOUTEK
Observers will be treated to a bright naked-eye comet at the end of this year and the beginning of next. Although it may be at an unbelievable magnitude of -7.7 at perihelion, it will be less than 5 degrees away from the sun, making observation difficult. Nevertheless, it should be easily seen before and after perihelion (on December 29) as a first magnitude or brighter object.
It was discovered (as nearly all comets are), on a photographic plate taken by a professional astronomer, Lubos Kohoutek, on March 7. At this time it was 16th magnitude. At North Mountain, an attempt to find it was unsuccessful, largely because of an interfering moon. Soon it will be bright enough to be easily seen in the 16-inch, and it will be the fourth one to be seen within the last 9 months.
The comet will pass from its present location in Cancer
to Leo and Virgo, to be seen in the morning sky by the end of the year. After perihelion it will be seen in the evening sky in the constellation of Sagittarius.
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Slavery. The ox. The horse. Sail. Gunpowder. Printing. Optics. Mechanics. Steam. Railways. Photography. Steel. Dynamite. Electricity. The telephone. Electronics. Radio. Internal combustion. Flight. Relativity. Atomic structure. Fission. Fusion. The sound barrier. Computers. The transistor. Integrated circuits. Lasers. Orbit. Reentry. The moon. Mars? The light barrier?
Man mounts the steps at an ever-quickening pace. We
stand in awe of the great minds of our time and of other times, yet hardly realize that we are but a few steps behind them on a great staircase leading upward. Not to infinity but to the end of man.
The preceding was submitted by Tom Tothill as an "Idea
for an Editorial". It had good impact, so it was put in as is.
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At the time of this writing, the future of the first Skylab mission seems in doubt. Shortly after a successful liftoff, trouble developed in the space station as the two major solar energy panels failed to deploy. With the launching of the astronauts delayed now, the mission will surely be reduced in duration and number of experiments planned. Much was to be gained from the astronauts observations of the Sun, Earth, and effects of outer space. This unfortunate occurance will slow our progress towards an understanding of the universe, but should not deter us from our ultimate goal.
Skylab should be visible to the naked eye occasionally at dusk or dawn, streaking quickly across the sky.
Look for this interesting configuration on the evening of June 2. Binoculars may help: occultation visible from Australia
CONTRIBUTORS TO THIS ISSUE:
Doug Beaton; 224-1789; 79 Meadowlands Drive West Jon Buchanan; 825-2636; 14 Kirkstall Avenue Rob Dick; 722-5809; 1855 Wembley Avenue Cathy Hall; 825-1628; Box 420, RR #2 Ken Hewitt-White; 733-4949; 2456 Beaver Avenue Chris Martin; 236-2868; 242 Powell Avenue Barry Matthews; 829-7237; 133 Woodridge Crescent, Apt. 1 Rolf Meier; 224-1200; 77 Meadowlands Drive West Doug Somers;8829-8609; 67 Costello Avenue Ed ter Heijden; 237-6905; 360 Frank Street Tom Tothill; B.C. Research, 3650 Westbrook Cres., Vancouver 167 Doug Welch; 829-2547; 35 Mohawk Crescent
Astronotes will not be published in July or August. Articles for the September issue are due by August 17.
Ms. Rosemary Freeman National Secretary The Royal Astronomical Society of Canada
252 College St., Toronto 130, Ontario