AstroNotes 1973 September Vol: 12 issue 07

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Vol. 12, No.7 $ 2.00 a year September, 1973
Editor: Rolf Meier 77 Meadowlands Dr.W., K2G 2R9
Addresses: Mary Grey Dominion Observatory, 994-5474
Circulation: Ted Bean 399 M cleod Street, K2P 1A5

EDITORIAL
As capital city, Ottawa has become the center for many activities. We have institutions for federal government, the arts, science, and learning. Visitors come from different parts of the continent to see Parliament or the National Arts Center. There is the Museum of Science and Technology. We have two large universities. There are the research laboratories of NRC, and the Central Experimental Farm. And one must not forget the Dominion Observatory.

Despite all these, there is an attraction missing, something which other cities in Canada have. We do not have any kind of planetarium. This is surprising because wherever there is a planetarium, as in Vancouver or Toronto or Montreal or even St. John’s Newfoundland, it is a meeting place for amateur astronomers. There they can get various kinds of astronomical publications and news. There is close cooperation between the amateur astronomers and the planetarium staff. The major purpose of the planetarium remains to be that of bringing astronomy to the public.

At this time it may seem that these functions are being carried out by the Dominion Observatory. But look at the subtle, important differences. A planetarium is in operation regularly, all days of the week. The Observatory depends on clear Saturday nights, with short views of single objects. A planetarium can have a staff fully devoted to informing the public of the visibility of planets, comets, etc., while the busy professionals at the Observatory must take time off their work schedule to answer phonecalls.

After night shows at a planetarium, a number of smaller telescopes would give the public a look at the "real" thing. This is where amateurs can help out, bringing their own telescopes, (possibly made in the planetarium workshop) and showing a variety of objects. The interested members of the public could find out about RASC meetings, held in the planetarium’s lecture theatre.

The planetarium would be an educational place, wherevery entertaing showings are held. In Ottawa, it would be a national planetarium, constructed as the best in the land, attracting visitors and helping to advance astronomy.

# # # # # # # # #
OBSERVERS GROUP MEETING - JUNE 1 Cathy Hall

With the departure of Ken Hewitt-White, our last meeting before the summer saw Ted Bean as our new chairman and Karl Poirier as our new vice-chairman.

Doug Welch showed several slides obtained in his asteroid searches, and urged all to try for shots of the Skylab space station - camera, tripod, and fast film are all you need.

Spectrography and solar flares were talked about by Barry Matthews, our solar coordinator. If you are interested in taking part in this sort of thing, give him a ring at 829-7237.

Grazes this past while have been zilch, according to
Karl Poirier, but keep your scopes out!

Our "meteor man", Chris Martin, is continuing work at the Quiet Site. If you don't have a telescope, then this is your field. Come out and join him in our observing "coffins". Meteors are plentiful, aurorae are common, and bats and wolf howls add variety. And, there is a good possibility that those reaching the "1000 meteor club" will soon receive recognition. A plaque has been suggested.

Next, Rolf Meier showed some more slides of Mars and
Jupiter, this summer's planets. They are starting to rise quite early in the evening. So get out in the warm weather and have a look at their various features.

Slides of the General Assembly were shown by Stan Mott and yours truly. This year's turnout was one of the best so far. Thanks to all the people that helped make it a success.

Lastly, announcements were made concerning a star night and constellation night during the summer. Hopefully we can stage more of this sort of thing in the fall.

ECLIPSE '73. WITH THE BAA Rob Dick

After about 15,000 miles and 25 days, this roving (broke) amateur has returned home!

It may be remembered that I was to view the eclipse on something not much better than a banana boat. Well, what we may have lost in size and luxury we made up for with a good captain, crew, and 30 seconds more of totality.

The Monte Umbe , flag ship of the Aznar shipping lines of Bilbao in Spain, is 507 feet long with a 65-foot beam. Originally she was an emmigrant ship to Brazil from Bilbao, in the early sixties. But now she does the run between Liverpool, Bilbao, and the Canary Islands.

I arrived in England on June 20 and sped to Liverpool to join a tour with the British Astronomical Association to Jodrell Bank. Our reception was cool to say the least. The huge 200-foot radio telescope, run by the University of Manchester, is on an impressive site. Particularly striking was the dish, greyed by haze, blinking in and out of view from behind the houses of the neighbouring town. We were restricted to a yard between their museum and the dish. Further more, there was no one there to answer our questions regarding the dish.

We left England on June 22, and headed south to Las
Palmas, Grand Canary. There we were shown the Apollo tracking station. Our tour consisted of parading us about racks of electronic gear. Anything further was left to the resourcefulness of some of the amateurs, such as walking about Πmile to the solar scope, where we were given a copy of the solar disc in H-alpha.

On the way back to the ship, Concord flew overhead on one of its test runs. She was laden with four experiments and followed the eclipse at supersonic speeds. We learned later from one scientist on board that they saw 70 minutes of totality.

We arrived early on the morning of the day of the eclipse hoping to find a number of buoys left by the British navy. They were to have marked the position of the line of totality. Apparently the native fishermen got there before us, because they were gone.

The captain manoeuvered us by guess and with a little help from charts and a directional range finder to within 3 ship-lengths of the line. From the duration of totality (6min. 5sec.) we determined our position to be very close to lat. 19° 37' 30" N, long. 16° 55' 12" W.

I was one of the fortunate few who had seen an elcipse before, with the March '70 under my belt and the attempt last year in the Gaspe. On my 8-inch reflector I had a Zenit B SLR camera at prime focus. My Pentax was mounted with a 150-mm lens and polarizing filter to photograph the corona under different planes of polarization.

Among other equipment on board were hundreds of other cameras, several small refractors and reflectors, and 634 eye-balls.

The bow of the ship was covered with cameras and people, still tensely waiting for the first diamond ring. It was hazy, with not a breath of wind. A few gulls soared about the ship until minutes before totality.

The diamond ring formed slowly, and then the corona erupted from the edge of the moon's shadow. Little or no color was seen other than the eerie silver glow of the streamers. A coronal "hole" was visible, an absence of the corona in the halo. The haze obscured all stars and only Venus and Saturn were recognized. The sky never got very dark. I could still read shutter speeds on my Zenit camera.

I had hoped to record the inner, middle, and outer corona with both cameras. My Pentax saw little due to the fast shutter speeds. The Zenit camera only has shutter speeds to 1/30, then a jump to "B”. It only saw inner corona.

High Speed Ektachrome was chosen for speed and color balance, but the results were rather grainy. I only took about 34 exposures, and for the rest of the time ( about 4œ minutes) I just stood and looked at it. No telescope can instill the awe of the spectacle as well as the naked eye can.

The corona makes the sun's diameter appear larger. The streamers appear as threads that are stretched out, holding the sun motionless until it is all over and it may move on.

After the eclipse, the date that was in most people's minds was 1976, and Australia.

WHAT TO SEE IF YOU WANT TO TRAVEL 9000 MILES Cathy Hall

Your first total solar eclipse is well worth travelling 4500 miles to Africa to see. This is an aftergone conclusion. Australia in '76 is next in my plans.

My little escapade all started when I accompanied my parents down to Toronto last November, and spent the day at the McLaughlin Planetarium. While talking to the girl that worked in the bookstore, Penny McCabe, the subject of the African eclipse was brought up. She mentioned that she was planning on going and told me to drop her a line if I decided to go. Little chance, I thought.

When I turned around I was In New York City, boarding the Canberra, 5th largest passenger ship in the world, bound for Africa. Penny, myself, and seven other RASC members had driven down by 3-car convoy, with about Œton of luggage. The others were John Morriss, Ralph Chou, Jim Cobban, Jim Low, Nick Fraser, Ugo Bartole, and Jim McKenzie.

Ship-board life is quite the thing. This was the first time I had ever seen the Atlantic Ocean, and also the first time I had ever been on a ship. I never had time to get seasick - we were immersed in a flood of activities which included talks given by Neil Armstrong, Scott Carpenter, Allen Hynek, Walter Sullivan, Charles Smiley, Fred Hess, George Keene, Isaac Asimov, and numerous others. We went swimming almost every day in one of the three pools, kept a watch for various kinds of sealife (in the ocean, not in the pools), and went up on the observation deck every clear night.

The southern skies were very nice, with Scorpius way up. We were about latitude 18° N, I would have liked to see the Magellanic Clouds, though. Well, maybe in Australia.

At 7 am of the morning of the eclipse it was 100% overcast. Breakfast didn’t go down very well. At about 8:30 it was 90% overcast. And then, Dr. Brooks did it again. It cleared! First contact rolled around at about 9:16 Canberra local time. Just before second contact at 10:27, it began to get dark over the sea of tripods, cameras scopes, and more scopes. And then, it was beautiful.

One member of our party could be heard to yell, "how do you change these #&%#$& camera settings?". Penny ran off a whole color roll of 36 exposures without looking through the viewfinder of her camera. Elsewhere, one woman asked her husband, "How do you get this to work?". His reply was, "Shut up, dear, and get out of the way!" Another went hysterical. One man had gone below to use the washroom and got lost, and didn’t make it topsides until after totality. Still another had missed the ship at Teneriffe, in the Canary Islands, had to fly to Dakar, Senegal to reboard, and he didn’t even have a chance to see any of the total eclipse.

Perhaps the thing that struck me most was the apparant angular size of the eclipsed sun. It was huge. Without the corona it gave the illusion of being the same size as the full moon when it is just rising. Of course, it was, though new, not full.

The sky was a fantastic blue color, about the same brightness as the night sky with a full moon. Saturn, Venus, Rigel, and  Betelgeuse were obvious. I didn't do much other looking around, but my eyes kept sweeping back to the sun. To the naked eye, the corona extended out to about 3 to 4 solar radii. I saw no shadow bands. Apparantly, others on board did.

The diamond rings were beautiful. Nothing could remotely compare to them. The sun was just disappearing, and the ring appeared, silently and quickly. At the end of totality it displayed the same elusive, awe-inspiring quality. I didn’t really see much of Baily's Beads, as such. There were several fine prominences. The chromosphere appeared as a multitude of tiny fires burning at the edge of the sun. This was just after the first diamond ring and just before the second diamond ring.

As for the corona, the closest thing I could say is that it had the same visual quality as the gaseous wisps one sees in M-42 on a clear winter evening, using our 16-inch telescope. It was intricately delicate, beyond description. It was unlike anything I had ever seen before.

At this point, I would like to thank Rolf Meier, without whose generousity I would not have had a telescope with which to view and photograph such a truly spectacular sight - the total eclipse of the sun, 5 minutes and 32 seconds, Africa, in 1973. I shall never forget it.

THE REPORT FROM LAT 19° 52' N. LONG 17° 10' W Ken Hewitt-White

Uh, yea, well we didn't actually get quite that far. The day before the giant eclipse of June 30, 1973, our ship the Massalia developed engine trouble and limped into the path of totality at only 11 knots. By eclipse time, we were still a bit off from the central line so that our bunch missed some 30 seconds of the maximum totality time. We note here that the Canberra also missed about 30 seconds but the much maligned Monte Umbe saw the whole thing to within .0036 seconds of predicted length. Well, we tried to get on the
Umbe...

Speaking for everyone on the Massalia I can safely say we had a marvelous experience just the same. New astronomical friendships have been made that now span continents and oceans. The eclipse turned into one mind 300 people that had come from all over the world to witness this event. Japanese, Mexican, American, Canadian and all manner of European peoples were together on the Massalia with only one thought in their head: ECLIPSE! The thoght must have had power because it overcame engine failure and haze to produce one of the most memorable eclipses in history.

As the last rays of the sun turned the rolling sea into a cold grey, first Venus and then Saturn shot out into the mid-morning sky. The latter was high overhead, in the Northern sky! The diamond ring became the subject of everybody's viewfinder and then, for those who were exceedingly quick, Baily's Beads offered a split-second photographic opportunity.

Totality was characterised by the long coronal dreamers and polar plumes of a sun halfway to sunspot minimum. One streamer stretched 3 solar radii to the south-west, while 60 degrees to the east an enormous dark notch daggered its way right to the solar limb, revealing no corona at all. Allthough water particles in the lowest part of the troposphere prevented this from being the most colorful of eclipsed suns, it didn’t lack in coronal detail. Through my 4œ-inch f/4 I could see a complexity of raial and tangential coronal structure that I hitherto imagined as being impossible. A number of small pink prominences soon (all too soon) began to give way to third contact, a point difficlt to define, since a large valley on the western limb of the moon produced one of the longest and most spectacular diamond rings in recent eclipse history, while others snapped as many asa dozen pictures, I watched the last presence of this great totality disappear. For some seconds after the shutters had stopped clicking I could still see the corona and blackened disc of the sun against the glare of the mature diamond ring.

Although there was considerable controversy over the  visibility of shadow bands (as opposed to smoke patterns from the twin stacks of the Massalia), our group saw them distinctly for more than two minutes before and after totality. This appears to be without confirmation from any of the other 3 ships in the area. But we DID see them. Perhaps reports will soon support this observation.

This giant of an eclipse did not pass without tribulation,
however. Engine trouble was not the only way in which Murphy made his presence felt. One of Allen Miller' s movie cameras mysteriously failed to work after flawless tests only minutes before eclipse time. My longer exposures revealed the slow roll and pitch of the ship in the form of "solar footballs”, elongated eclipsed suns that began on one side of the frame and ended on the other.

And the most heartbreaking of all: David Dodge ran off
a set of really tremendous totality shots on High Speed Ektachrome, perfectly focused, and beautifully framed, but they were put through a black and white developer. Now, can you just believe it...

But potential disaster was averted too. John Tanner
had massive camera failure only a minute before totality but miraculously smashed it into working order just in the nick of time. And another fellow got to 2nd contact and became so overwhelmed he just gave up on photography, but still thought it was a 300% success. His "disaster" occured in Iceland, where he lost over half his money, forcing him to hitchike all the way through Europe and Africa with a 4-inch and 6-inch telescope on his back. We met up with him in Cassablanca. He joined our crew on the Massalia and made his giant eclipse trek a success after all.

And perhaps that is what makes eclipse chasing such a special thing. People from all over the world meet each otherand they help each other, and together they witness nature’s most spectacular coincidence - a total eclipse of the sun.

COMET KOHOUTEK 1973f by Jon Buchanan

With summer ending, as well as its various activities, everyone returns to review all that has happened and discuss what will happen. And what will happen? One of observational astronomy’s major events of this year, Comet Kohoutek. Predictions are calling for it to be the best comet of this century, perhaps more spectacular than Hailey will be!

This comet comes at a time when interest in comet observations has started to pick up, and when memories of Bennett and Heck-Sause are fading.

Comet Kohoutek is even supposed to be visible in daylight. Since this is a rare event, and one for which plenty of advance notice has been given, now is the time to plan a project for this event.

One project that comes to mind immediately is filming
the comet from when you first find it to when last seen, some time in 1974. Everyone with a camera will probably try this.

Another project if you don't have a camera, or even if
you do, is to draw the comet.

What else is there to do? Another project could be plotting the comet’s path in the sunrise twilight of December, and sunset in January. This will challenge everyone and anyone willing to try.

Another project, since Kohoutek will be visible in daylight , is to observe it as soon and as long as this is possible; what it looks like, and by using the sun as a reference point, plotting its motion and seeing how fast it moves at perihelion (closest approach on the 28 December).

One word of caution with daylight observations, especially with telescopes: Don’t look near the sun unless something blocks its light off, such as the edge of a building. Also a note for camera operators: if you don't shield your lens, solar glare will result in your picture.

As I said before, there is time for planning now. Maybe you can come up with something else as a project. I've only mentioned some of the obvious ones that come to mind.

To give some idea of where and when the comet is in relationship to the sun, the above drawing may be referred to.

THE MOON Barry Matthews

In previous articles I have discussed various programs
for the lunar observer. The British Astronomical Association has a number of programs that they cover on a continuous basis. One is ’Project Moonhole':

"The purpose of this project is to study the profiles of craters with diameters in the range 1 0 - 2 5 Km . The craters chosen for study lie approximately in the central region of the visible disc so that problems of foreshortening are kept fairly small.

The image size of the craters is such that i t is virtually impossible to obtain precise values for the fraction of the diameter in shadow at any given time. Measurements using instruments, such as a bifilar micrometer, do not produce results superior to straight forward visual estimates. It is, therefore, more practical to obtain values for the depths of these craters by the use of statistical techniques from large numbers of observations.

Results so far have shown that the method is capable of giving reasonably accurate results. The ma in requirement is, however, to have available observations for the whole of the period during which the crater is partially filled with shadow. Ideally, observations are required in equal numbers for sunrise and sunset conditions, but this is unlikely to be achieved due to the fact that the latter occurs when the moon is visible in the morning sky. Nevertheless, such observations are requested and are considered top priority.

The idealised condition is illustrated above. The observer is requested to estimate the fraction x/d filled by shadow and then convert this value to one expressed in decimal form.

The list of craters currently being studied appears at the end. Each crater is given two numbers: the odd number refers to the sunrise condition, and the even number to the sunset condition (i.e. after full moon). The reason for using different numbers is that the measurements of the value of “ f " are calculated from different sides of the c rater. In this discussion, the ambiguity of the meaning of "e a s t ” an d “west" walls is avoided by referring only to ‘‘before" and “ after" full moon.

If observation is made before full moon use odd number
If observation is made after full moon use even number

Much consideration has been given to extending the list of craters but it has been decided, however, that at the moment there is no point in extending the list until the craters already listed are adequately observed.

Completing the Report Form
It is essential that the report form is completed in exactly the manner requested, otherwise the observation may be rejected. This format is required so that the amount of editing is reduced to a minimum before being processed by computer personnel.

Time: use Universal Time only and express in the form: 2 0 . 3 8 : 0 1 .5 7 . Always have two figures before and after the point.

Crater Number: use the correct code number for the crater under observation: odd number before full moon even number after full moon

Fraction: the fraction of the diameter in shadow at the time of the observation. This must be given in decimal form with a “ zero" before the decimal point, e.g. 0 .4 ; 0 .6 5 .

Telescope: indicate the size of the telescope used for the observation. Express this in centimetres. If the telescope is a refractor, prefix with a minus sign.

Seeing Conditions: use the numerical code:
Poor 1
Average 2
Good  3
Very Good 4

Example

Time        Crater Number Fraction        Telescope Seeing Conditions
05.25     86             0.82         26        3
05.41        40             0.4        -15        3
18.50        15            0.05         12        1

LIST OF CRATERS
Odd numbers for sunrise shadow’s; Even numbers for sunset shadows

Crater       Lat Long Numbers     Crater       Lat Long Numbers
Theon Jnr     2S    16E    1    2    Seeliger    2S    1E    49 50
Theon Snr    1S    15E    3    4    Manners    5N    20E    51 52
Schmidt    1N    19E    5    6    Ariadaeus    5N    17E    53 54

continued...

The proceeding article was taken, with permission, from
the BAA's "Guide for Observers of the Moon".

At present I am reducing my own data by hand and hope
to get a copy of the program from Patrick Moore of the BAA. I will have a finder chart at the next meeting for anyone who might be interested in this program. Patrick Moore has expressly asked for "even" number observations (sunset) and will gladly process our observations and send us the results.

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A CONSTELLATION REVIEW (2) Doug Somers

This month we set our sights towards Delphinus, a small constellation tucked under Vulpecula and bordered by the Milky Way on its western side. The proximity of the Milky Way brings two planetary nebulae within the boundaries, and from the darker portion of the sky without the dusty background of the Milky Way, we get two globulars.

On the Delphinus-Aquila border1we find NGC 6891, a planetary nebula at RA 20h 12m 46s, Dec 12° 34' N. The disc is 15" x 7" and appears stellar at 20 x; 100 x is recomended to view the 11.4 magnitude object. The central star is 11.6 magnitude, so it should be within the reach of a 3-inch or larger telescope.

I recommend starting from Beta Delphini and proceeding west to Rho Aquilae. From Rho, go 2ϡ south and 2 min of RA east. This planetary makes a triangle with two 8th magnitude stars, one 10' to the north, and one 10' to the south-east. At present, 6891 is 1740 parsecs distant, and is receding at 42.1 kilometers per second. This object was discovered in 1884 by R. Copeland.

We go northward to our next objective, NGC 6905, an 11.9 magnitude planetary nebula found at RA 20h 20m 9s, Dec 19° 56.6' N . The disc is larger than 6891, being 44" x 37”, but it is fainter by .5 magnitude. The central star will require a 10-inch or larger with good conditions, as it is 14.2 magnitude.

To find this object I suggest working from Gamma to Eta Sagittae, then sweeping 17 min of RA to the east. The object is slightly north of your stopping position, but with a wide field ocular, it should be in view. The background of the milky Way should enhance the beauty of the field, providing coarse clusters of stars around the planetary. The surface brightness of 6905 is about half that of M-57, the Ring Nebula.

Present calculations tind this object at 2190 parsecs and approaching at a rate of 4.3 kilometers per second. One of my sources gives conflicting information on the discoverers of this planetary. In one place William Herschel is said to have discovered it in 1782, and in a later place John Herschel, William' s son, in 1831.

About 4° due south of Epsilon Delphini, we find NGC 6934, a small globular cluster. This is a fine object, yet it seems most amateurs neglect it. Shining with a light of 9.2 magnitude, this object is located at RA 20h 31m 44s, Dec 7° 14.1' N. The adjective "small" fits this 1.5* diameter object quite well. The distance of 6934 is 16.5 kiloparsecs and it is approaching at 360 kilometers per second.

To find this object you can either try a 3° 50’ sweep south and a 1 min to 2 min RA sweep to the east starting from Epsilon Delphini, or star-hop from Epsilon to Chi, and continue until you reach the desired field. The accompanying maps should help.

Fifteen minutes of RA to the east of Gamma Delphini we find another globular cluster, NGC 7006. It too is a "mini-globular", found at RA 20h 59m 10s, Dec 15° 59.5' N. This 10.3 Magnitude object is even smaller than 6934, being 1.1 min in diameter. This object is 60 kiloparsecs distant, and is approaching at 348 kilometers per second. To find 7006 do a 15 min eastern sweep from Gamma Delphini.

NGC 7006 is readily detectable in a 3-inch telescope. It appears small and concentrated in most instruments, and at a glance may be mistaken for a 10th magnitude star. It appears as a faint spot in smaller, lower power instruments.

For double star freaks, whether they use telescopes, or like one person I know, opera glasses, Gamma Delphini is a very nice object. It rates as one of the 105 best deepsky objects compiled by James Mullaney and Wallace McCall. Its components are 4.5 and 5.5 magnitude, and are separated by 10 seconds of arc. The position angle is 268° and most observers see these stars as being yellowish, although those with larger instruments may see one star as being pale green. Other tests are 1 Delphini, mags 6.1 and 8.1, separation .9 sec, PA 346°, and B Delphini, mags 4.0 and 4.9, separation .45 sec, Pa 325°.

Happy Hunting. 1Most catalogs say that 6891 is in Aquila, but its
disc extends into Delphinus.

CLASSIFICATION OF PHOTOGRAPHIC PAPERS Doug Beaton

Contrary to common belief, a photograph is not just a piece of paper with a picture on it. Photographic papers may be classified under several heakings such as tone, brilliance, texture, contrast, speed, or printing index, grain , hardness, weight, and color.

Tone refers to the colors of the blacks and whites produced. For example, whites may be cream, ivory, or snow colored, while blacks may range from dark bluish to jet blacks. Tones are usually referred to as being either warm or cold depending on how harsh the colors appear to the eye. Glossy surface papers have a wider range of tones than the matte papers.

Brilliance is a quality of the paper surface. Although
there are many types available, the main three types are glossy, semi-matte, and matte. There is a great latitude in choice, however, since a glossy paper may be dried to a duller finish or a matte paper given a shiny appearance through a different process.

Texture is a quality of the paper's base. Although not as readily available as ordinary papers, surfaces such as tween, rayon, tapestry, cloth, and velvet are produced for various purposes.

Grain exists on papers just as it does on films. There is a wide range of fine and coarse grained papers available at most stores.

Contrast is sort of the ability of the paper to reproduce grey tones. A high contrast paper will record dark blacks and brilliant whites with a few tones of grey in between. A low contrast paper will have more greys with less extreme blacks and whites. Kodak, Dupont, and Ansco all produce variable contrast papers, whose contrast can be varied through the use of filters. Contrasts are graded in numbers from 0 to 6, with zero being the lowest contrast and six being the highest. Only Spiratone and Agfa make a contrast six paper. Developer, exposure, and even enlarger type will affect the final contrast of the print.

Printing index or speed can be likened to the ASA numbers of films. As in films, the higher the contrast the paper is then the slower the emulsion is. For Kodabromide, the printing index numbers are: 500, 320, 200, 125, and 100. These are for contrasts one through five respectively. If a picture requires a 10-second exposure on contrast one paper then it will require a 500/200 x 10, or 25 seconds on contrast three paper to achieve the same density scale. Ilford papers are all at the same speed except for their contrast five paper which has half the speed of the others. I have found that Ilford’s speed index is about 250 in relation to Kodak.

Hardness is a function of contrast and paper grade. The
warm toned papers are usually of low contrast and they are considered soft. A high contrast, cold toned paper is called hard.

Weight refers to the thickness of the paper. "Air
mail" papers are extremely thin, single weight papers are normal thickness, and double weight papers are about twice as thick.

Color. By this I mean that you can buy in most stores
papers which print like ordinary black and white papers except that they have been colored in a variety of flourescent tones. There are ten colors available. The red color, which is the only one I have used was of low contrast with a matte surface. They are twice as expensive as the ordinary papers.

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Contributions for the next issue of Astronotes are due September 14th.

Contributors can help greatly in the production of Astronotes by typing their articles at 60 characters to the line. This makes it easier to estimate the length of the article in terms of Astronotes page-lengths. Also, contributors should watch their grammar and speling, because your Editor can’t always find his dictionary.

Keep your articles relevant and to the point. Don’t try ideas which have already been used, such as duplicating a series already in progress.

One final note: calculate your articles to exactly fill an even number of pages, or risk me rambling on and on and on...

ASTRO NOTES

TO
Ms. Rosemary Freeman
National Secretary
The Royal Astronomical Society of Canada
252 College St., Toronto 130, Ontario