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The Newsletter of the Ottawa Centre, RASC
|Vol. 13, No. 3 March, 1974|
Editor...... Rolf Meier...77 Meadowlands Dr W....K2G 2R9
Addresses....Earl Dudgeon,545 Bathurst A v e .K1G 0X4
Circulation...Ted Bean 399 McLeod Street......K2P 1A5
REPORT ON QUASAR OJ 287 (2)
A quasar has been defined as a star-like radio source. A quasar is thus discovered by radio astronomers so a radio source, and when the object is pin-pointed optically, it turns out to be star-like. The spectrum of many quasars is tremendously red-shifted, with receding velocities so great that they must be at the edge of the universe. If they are so far away, then why are they such intense radio sources? The energy being emitted is greaterthan from known galaxies, so they must be very large. This would not be impossible to accept, but for the observation that quasars such as OJ 287 and 3C 273 vary their output of energy over short periods of time.
Our observations of these quasars has attempted to establish just how short these periods of time are. It must be pointed out that any substantial variability in an object such as this must be considered quite remarkable, and it is little easier to explain variations over days than minutes. This is because for an object to be producing so much energy it should be quite massive. Variations cannot easily be expected to occur faster than the time it would take for light to travel across the object, several hundred thousand years for the average galaxy.
The fact is that OJ 287 does vary. Reference to the individual graphs in the previous issue of Astronotes is not conclusive, because the variations are within the uncertainty of the observations and photographic measurements. One way to obtain more meaningful results is to obtain a very large number of estimates. Statistical methods can be applied and random fluctuations eliminated. Observations of OJ 287 and 3C 273 will continue with this in mind.
The report from professional astronomers is that OJ 287 varies over "short" periods of time, but the only figure that can be attached to that word is the 40 minutes reported in a past IAU circular. From last year to this, it can be said with certainty that OJ 287 has dropped in visual magnitude from about 13.6 (± . Z) to 15.3 (±.2). That is a factor of 5, and it is certainly hard to explain in view of the present knowledge.
OBSERVERS GROUP MEETING - FEBRUARY 1
The theme of this month's meeting was how to deliver a message and not appear ill. In short, it appeared as if the majority of the 42 people attending were stricken with "the plague”.
Dr. Lossing delivered a short talk on light, explaining its properties and its causes. He suggestes a continuation of his talk at future meetings on subjects such as emission spectra and synchrotron radiation. This proposal received a unanimous "yes” decision and we look forward to his promised deliveries.
Cathy Hall showed several outstanding slides of Comet Kohoutek taken at various times in January. We had an unexpected visit from a Toronto friend, Jim Low. He showed slides of his recent eclipse voyage to Acapulco.
Mr. Howard Harris presented an excellent slide of the Milky Way. Also shown was an interesting slide of Dr. Lossing, "au naturelle.” Doug Welch wrapped up the slide show by delivering a talk on atmospheric phenomena. On the lighter side, he showed his "mistake slides”, bringing back perhaps familiar memories to us all.
Barry Matthews, suffering from the worst of the plague, encouraged group activity. He proposed observation of occultations and the submitting of monthly reports toward helping more accurate occultation timing.
Rolf Meier also spoke on occultations. He organized a lunar grazing expedition for the 25th of February. If he can make it through the reams of computer printout paper, Rolf hopes to organize more of these grazes in the future. Karl Poirier, a lunar graze veteran, offered much luck in the endevor.
On Saturday, February 8, the first of a series of seminars for beginners was held. This first meeting consisted of a trip to North Mountain Observatory to observe the telescope housed there. We hope the turnout to these sessions will be good.
The meeting closed with the presentation of awards. Congratulations to Doug Welch, for receiving the Observer of the Tear Award. Jon Buchanan presented the Variable Star Award to Rob McCallum for observing 6 variables a total of 262 times last year. Jon also reported that award standards would be changing for the upcoming year.
After a short film, the meeting was adjourned, to coffee and coke.
OBSERVATIONS OF COMET KOHOUTEK
Observer Date Instruments
F. Lossing Jan.4 10 x 50 binos
C. Hall Jan.7 8 x 30 binos
R. Meier Jan.8 10 x 50 binos
C. Hall Jan.9 8 x 30 binos
R. McCallum Jan.12 7 x 35 binos
C. Hall Jan.13
-better in binoculars
-too diffuse in 'scope
-sky not completely dark
-tail split, 4°-5°
-nucleus mag 3, compared to beta Cap.
-just above, to left Venus
-easily seen naked eye,tail 4°-4½°
-picked up with HSE in15 sec. exposure
-first view in dark, moonless night
-tail extends 50% beyond 5° field of binos
-could see 7°-8° nakedeye tail
-comet at its brightest
-9° tail on photo
-"what a sight!"
-4th mag naked eye
-in 16-inch, head small, 10' maybe; no detail in tail
-best in binoculars, with 7°-10° tail
-tail narrow, double, south side brighter
-tail PA 330°
-10-min. exposure with 12" Aero-Ektar lens shows nucleus at mag. 5.5
-tail very straight, uniform, no irregularities
C. Hall Jan.17 8 x 30 binos -hazy conditions
-approx. 5 or 6 nag nucleus seen in binos
-tail about 2½° long, but not seen naked-eye
C. Hall Jan.19 8 x 30 binos -10-min exposure on HSE shows 6° tail
- around 6th mag.
C. Hall Feb.9 16-inch,125x -comet very near galaxy NGC 524
-approx 10th mag, no visible detail, almost roundish fuzzy patch
THE ZODIACAL LIGHT AND THE GEGENSCHEIN
These two phenomena are extremely faint, and require very clear skies to be seen. The Gegenschein is far fainter than the Zodiacal Light, and requires the very clearest conditions. Both have been observed at North Mountain, and the Zodiacal Light can be regularly seen on any decent observing night. The Gegenschein, on the other hand, must be very favourably placed to be seen.
What are these "lights"? The Zodiacal Light is a faint, homogenous, triangular patch of light which closely follows the ecliptic (hence "Zodiacal"). It is brightest and widest nearest the sun, but of course this part can never be seen because of solar glare. The brightest portion is seen as soon after evening (or before morning) twilight as possible, and is about as bright as the Milky Way. As the band follows the ecliptic away from the sun, it becomes fainter and narrower, usually fading out at an elongation of about 90° from the sun.
The Gegenschein is a very faint, homogenous, large, round patch of light which is always on the ecliptic at an elongation of 180° from the sun (ie, directly opposite the sun). When I have seen it, it would have just fit into the Great Square of Pegasus, which was conveniently nearby for comparison.
Neither of these phenomena is visible if seen against the Milky Way. The best time for the Gegenschein is always midnight, on a very clear, moonless night, when in a fairly blank region of the ecliptic above the celestial equator, such as Aries and Pisces, or Leo and Cancer.
The Zodiacal Light is best seen in late fall and late winter, when the ecliptic meets the horizon at its most nearly vertical position just before morning and just after evening twilight respectively.
The two phenomena are very hard to photograph or to see in instruments because they are so large, faint, and fade out gradually. The best lens would be fast and wideangle. Even so, care must be taken not to center the light in the field, otherwise the gradual fading cannot be distinguished from simple vignetting caused by the lens.
What is the cause of these strange lights? They are probably caused by sunlight reflected from millions of tiny meteoric and solar particles. The brightest region is closest to the sun, where the incident light is more intense and the particles possibly more numerous. There is an additional brightening opposite the sun where the particles reach the "full" phase. The two have also been described as atmospheric phenomena, but observations made in space don't confirm this.
In March, look for the Zodiacal Light just after evening twilight in the west, in clear country skies. The Gegenschein will be in the Leo - Virgo region. Let us know what you see.
We need only a few more members in the Ottawa Center to put us over the "200" mark. This means that we may have an additional national representative. To help us reach that goal, encourage your friends who are interested in astronomy to join and share the benefits of being a member of a group dedicated to the advancement of astronomy.
On page 418 of the December issue of Sky and Telescope is an advertisement showing how an astronomical photograph can be enhanced through the use of a linear radial transmission filter. Not having the $12.95 to buy one, I sent a letter to this company asking for more information. Within a week I received a hand-written reply (and this was during the Christmas weekend, too): "A LRTF kit contains a 2"x2" mounted glass filter with clear aperatures of ½" to 1¼". You have to provide support to hold them under or over your enlarger lens. In addition, a 12-page booklet gives detailed set-up and operation instructions.
An extra information sheet tells the actual steps used for the Mars example, and suggests other uses for the IRTF. Each kit is registered and you may get a refund if not satisfied. Exchange may be made at any time if the filter is not damaged and if you pay postage both ways (24¢ from me to you)."
They also included the following account of the principle behind the IRTF: "A LRTF consists of an optical quality neutral density filter which has maximum transmission in the center and has a linear drop in transmission radially out from the center. "When a LRTF is placed at or near the stop(location of lens iris) of an enlarger lens, then the focused image is not affected, but an out of focus image will change considerably. The out of focus image of each point on the negative becomes a small image of the LRTF. This small image will be called the unsharp smear. The intensity
across each diameter of the unsharp smear is triangular.
This is the reason for the high efficiency of the LRTF method. When the entire negative is considered rather than individual points on it, the net effect of the IRTF is to blend detail up to a scale determined by the amount the enlarger is out of focus. At the same time, the blended image accurately retains the basic character of the negative for detail larger than that blended (this is not true without the LRTF). "This efficient blending action can be used several ways. For example, when a grainy image is defocused so that the unsharp smear radius is equal to or larger than the average grain clump separation, the graininess blends out to a large degree with little loss of detail. The same technique can remove half tone dots (newspaper or magazine photos), or television scan lines.
"With additional steps, the opposite effect can be achieved, i.e., enhancement of small detail. To do this the LRTF is used to make an unsharp mask. If the masknegative stack is printed at very high contrast, the fine detail will show up better. In fact, slightly out of focus photos will sharpen up as well as show fine detail better. "The methods can be used on many types of photos, from medical X-rays to portrait photos, for black and white and color."
Of the four space probes the Russians have sent to Mars, one has gone into orbit. The four probes, Mars 4, Mars 5, Mars 6, and Mars 7, were launched last year. While Mars 5 went into orbit, Mars 4 flew past the planet, apparantly because the retro-rockets failed to fire. It did take some pictures, though, as it came within 1400 miles of the surface of the planet.
The two other probes are still on their way, and may be scheduled to land on the surface. Mars 5 will act as a radio link to Earth then. If the Russians succeed, they will have beaten the Americans by at least two years, and take a giant leap in the exploration of planets.
Please call Barry Matthews (829-7237) if you can spare any equipment (especially eyepieces) for use in the equipment library.
Our own Dave Penchuk has had the dubious honor of having his photographs of Comet Kohoutek published on the front page of The Charlatan, that outspoken voice of the student body of Carleton University. Dave will have autographed copies suitable for framing available at future meetings, complete with corrections of the errors made by the editorial staff of The Charlatan.
RECENT IAU CIRCULARS
Out at North Mountain Observatory on the bookshelf is a pile of circulars from the International Astronomical Union which grows higher regularly. Have you seen it? Have you read them? They’re just packed full of interesting pieces of information.
Did you know that in this past month (February) there were no fewer than 10 comets up and about? Comet Forbes, 1974 a, was in the bottom part of Ophiuchus on the 2nd at magnitude 19.4, and will move into Sagittarius, and then the bottom of Aquarius in the first week of July. At this point it will have risen to magnitude 16.9. On August 1st Forbes will start on its path outwards from the sun (c.2625).
Comet Sandage, 1973 k, was in Corona Borealis at magnitude 17 (c.2622).
Comet Heck-Sause, 1973 a, was in the north circumpolar region, in Camelopardus, and will be in Perseus by June. It was magnitude 20.2 on the 2nd, and is fading (c.2552).
In the constellation of Cancer we have Comet Gunn, 1969 II, which is at its brightest in February and March at magnitude 18.8. By June, it will have started to grow fainter once again (c.2554).
Then we have Comet Gibson, 1973 o, which was in lower Eridanus near the beginning of the month at magnitude 16.4, and will be in Horologium at magnitude 17 by June 2nd (c.2620).
Just off the Milky Way, near Delphinus, there is Comet Kojima, 1972 j, at magnitude 20.5. It has just come downwards from in the Square of Pegasus (c.2530).
Beside Pegasus, in the constellations of Aries and Pisces, we have a most interesting situation. There are four comets right now in that area! First there is Comet Schwassmann-Wachmann 2, at magnitude 18.9 on February 2, down to the right of Aries. It will grow fainter and in the first week of April will enter Taurus (c.2527). Comet Gehrels 2, 1973 n, was just below Aries on the 2nd, and will be in the Hyades near the end of April. During this period it will drop from magnitude 16.6 to magnitude 17.7 (c.2622). Next, Comet Encke, which returns about every 3.3 years, is back again at about magnitude 15, just left of the head of Pisces (c.2547).
Lastly, there is Comet Kohoutek, which when I saw it last (February 9) was about magnitude 10, and between Aries and the head of Pisces.
It had faded immensely, and had really no discernable tail.
Besides giving position and magnitude predictions for comets, the IAU circulars provide observations of actual magnitudes, lengths of gas and dust tails, presence of antitails, and special features.
On November 29th, Kohoutek's tail was 3.8° long, with a large knot of material 1.9° from the nucleus (c.2604). On December 27th, our "Christmas Monster" had a total magnitude of greater than 0, and perhaps greater than -3, as seen by the Skylab crew, and 3 days later developed a spike-like antitail pointing towards the sun (c.2614). On January 16th, a 13° naked-eye tail was visible...from South Baldy, New Mexico (c.2631)! On
the following night, a split in the tail had developed about 8° back from the head (c.2623). On January 27th, Kohoutek was still visible from South Baldy with the naked eye (c.2626).
You may ask at this point exactly how many of these comets we can actually see. Many are obviously too faint for small telescopes. Many are even too faint for our 16-inch telescope. Visually, that is. But photographically, several could be picked up using time exposures. Consider another point. In just one small section of the sky, there are presently 4 comets saying "ha- bet you can't see me!". Just think how many more comets there must be just waiting to be found - not necessarily faint things, but objects accessible with amateur telescopes.
These IAU circulars also contain information and observations on asteroids, variable stars, radio sources, supernovae, occultations, transits, planetary activity, and new unexplained phenomena. A supernova was discovered below M 97 in Ursa Major, magnitude 17 on December 24th (c.2624). There is one near delta Andromeda, at magnitude 16.5 (c.2620). There is one in M 66, a spiral galaxy in Leo, at magnitude 14.5 on December 19th (c.2624).
You can see the wealth of material these IAU circulars contain. Certainly, it would be to your advantage to read them once in a while, to see what information pertains to your particular interest. So, next time you are out to North Mountain, browse through them. I've put them in chronological order in a box file so they're easier to refer to.
After my talk at the last Observers Group meeting, I felt further enlightenment might be in order. First of all, what is an occultation? An occultation is when a portion of the moon passes between the observer and a star. On its journey around the earth, the moon moves through an angle about equal to its diameter every hour. When a star suddenly winks out on the east limb (imaersion/ I) and reappears at the most an hour later on the west limb (emmersion/E ) the observer has witnessed an occultation.
All that is left is for the observer to determine the time, and the position he or she saw it from. To find the observer's position is beyond this little talk, and all that is required is the latitude and longitude.
To restate the various columns in the Observers Handbook is the object of the next few statements. There is an error in the handbook on page 58. The date at the top of the page should read 1974 and not 1973. The remining data is correct. Column #1 gives the date. Column #2 gives the common name of the star. Column #3 gives the Zodiacal Catalog (ZC) number of the star. Column #4 gives the magnitude of the star. Column #5 uses I or E to indicate whether the event is an immersion or emmersion. Column #6 gives the elongation of the moon. Elongations of about 0°, 90°, 180°, and 270° correspond to new, first quarter, full, and last quarter phases respectively. When elongation is less than 180° a star will disappear at the dark limb and reappear at the bright limb. Columns #7-#10 are for the standard station of Halifax. Columns #11-#14 are repeats of Columns 07-010 but for Montreal. Column #7 is Atlantic Standard Time (AST). Column #8 gives time corrections for the difference in latitude and longitude from the standard stations.
Column #9 gives time correction. Column #10 gives the position angle of the point of contact on the Moon's disk. This is measured from the north point towards the east.
To take an example: (page 58)
March 2; Saturn; - ;0.2mag; immersion; elongation 107°; no occultation at Halifax; 17 hrs. 48.9 min. EST; - ;- ; 170° east of north is the point of contact (for Montreal) in plain language. On March 2 Saturn will be occulted by the moon's dark limb. There will be no occultation at Halifax, but the event will occur at Montreal, Winnipeg, Edmonton, and Vancouver at 17 hrs. 48.9 min, (at Montreal) 17° east of North around the moon's limb.
How do you time this event?
This is easy. Using the largest size scope available set up at least 15 minutes prior to the event. The following equipment will be required:
-medium power eyepiece
Set the radio to CHU and start your recorder, ensuring that the time signal is being recorded. Find both the object being occulted and the moon. In the case of Saturn, time 1st contact of outer ring, 2nd contact for inner edge of ring, 3rd contact for edge of the globe, 4th contact for the next edge of the globe, 5th contact for the following inner edge of the ring, and 6th contact for the final edge of the ring. Remember that about
an hour later Saturn pokes out on the bright side.
After these events have been recorded and analized in the comforts of home, give all particulars to Barry Matthews. Time as many events as you can using the handbook as a guide.
Dr. Vic Gaizauskas has sent me the following address for information on the 1974 eclipse in Australia:
Mr. Alan Driver, National Standards Laboratories, CSIRO,
City Road, Chippendale, 2008, Australia. Mr. Driver can provide information concerning meteorological conditions, customs, visas, possible observing sites, etc.
Barry Matthews has recently been observing the planets in the early morning hours. One day, he decided to see what he could see, and he looked toward Venus. Lo and behold, he could sees definite crescent with 7 x 50 binos. He would like to hear reports of similar events with binos
of the planets.
NEWS FROM OTHER CENTERS
John Tanner and Allen Miller of the Vancouver Center have returned from the tropics where they had hoped to see a spectacular annular eclipse of the sun, framed by Venus, Jupiter, and the giant Comet Kohoutek. Although the eclipse itself was well observed, the sky was not as dark as expected. Neither Kohoutek, Jupiter, or Venus was seen. They did have nice views of the Southern Skies, having travelled as far south as Panama. Allen hopes to see the eclipse in Australia this year, his lifetime ambition being to chase eclipses.
- There will be an occultation of the planet Saturn by the Moon on March 2.
- The minor planet Vesta comes to oppositon on March 31. The Observers Handbook (RASC) gives the opposition magnitude as 5.9, but the BAA Handbookgives the magnitude as 6.8. In fact, looking through the magnitudes for asteroids listed both in our handbook and the BAA Handbook, those given by the BAA are consistently .9 mag fainter. To find out for sure who is right, the best thing would be to follow these asteroids and make estimates. The positions, and even a map for Vesta and Ceres can be found in our handbook. For information on many more, contact Doug Welch.
- A very minor shower, the Corona Australids, is the next meteor activity for (and in) quite some time. Although the radiant never gets higher than 3 degrees below the horizon, with a zenith hourly rate of 5 meteors, this shower will be observed just so that we can say we have done some meteor observing. The last 3 major showers were not observed for one reason or another, so it is about time we got into some activity. The maximum occurs on the night of the 15/16 (a Friday), so leave that date free for meteor observing. Call Holly Allan at 733-1931 for information.
Pluto comes to opposition this month at 14th mag. Use the map below as a handy guide. Numbers beside stars are mags.
CONTRIBUTORS TO THIS ISSUE
Doug Beaton; 79 Meadowlands Dr. W .; K2G 2R9; 224-1789
Holly Allan; 2180 Alta Vista Dr.; K1H 7L8; 733-1931
Cathy Hall; Box 420, RR#2; K2C 3H1; 825-1628
Fred Lossing; 95 Dorathea Dr.; K1V 7C6; 733-2715
Barry Matthews; 133 Woodridge Cr., Apt. 1; K2B 7T2; 829-7237
Rolf Meier; 77 Meadowlands Dr. W.; K2G 2R9; 224-1200
Articles for the April issue of Astronotes are due by March 22.
Ms. Rosemary Freeman RASC
The Royal Astronomical Soc. of Can..
252 College St.
TORONTO 130, Ont.