AstroNotes 1982 April Vol: 21 issue 04

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ASTRONOTES ISSN 0048-8682
The Newsletter Magazine of the Ottawa Centre of the RASC
Vol. 21, No. 4 $5.00 a year April, 1982
Editor....... Rolf Meier.......4-A Arnold Dr......820-5784
Addresses.... Art Fraser.......11-860 Cahill Dr...737-4110
Circulation...Barry Matthews... 2237 Iris St.......225-6600
IRORI BACK ON THE AIR Frank Roy
The radio telescope at IRQ was put back into operation
in early February. It had been down since August, after
one of the front-end amplifiers died of water
contamination. After the amplifier died, antenna
measurements were made by Ken Tapping and it was found that
the antennae were tuned for 232 MHz, but the amplifiers
were tuned to 238 MHz. A decision was made to rebuild new
low-noise amplifiers and tune them to 232 MHz.
The new front-end amplifiers have a much higher gain
per stage that the old ones did and so only 4 are required
instead of 10. The new units have about 30 dB of gain
each.
As a result of the new amplifiers and retuning the
frequency to 232 MHz, we have effectively lowered the noise
floor from 250 Jansky to 75 Jansky. We should now be able
to detect radio sources stronger than 75 Jansky. This
figure was determined by examining fringes obtained from
Hercules A, the weakest source so far picked up with IRORI.
The old equipment rack for the radio telescope was
replaced on Saturday, March 20, by a 19-inch rack. The new
rack stands about 4 feet high and has wheels, thus making
it much easier to use and freeing up roon in the clubhouse.
Several projects are planned for IRORI, including
digital signal processing with my Apple computer, a digital
analysis of the antenna system, and improvements in rf
sensitivity, dipoles, and phasing system.
* * *
Articles for the May issue of Astronotes are due by
April 23.
-1-THE PLANETS IN APRIL Rolf Meier
The closest approach of Mars to the earth during the
current opposition takes place on April 5th. At that time
the apparent diameter of the planet will be about 14.7", not
the largest possible (in 1971 it was about 25"), but still
a respectable size. The month of April should provide the
opportunity to observe some of the albedo features on
Mars. Most of the features shown on the map on page 92 of
the Observer's Handbook 1982 should be visible in a 6-inch
or larger telescope under good seeing conditions.
Jupiter and Saturn come to opposition in April, and
together with Mars should make for planetary observing in
the coming month.
Something to watch for on Saturn's rings are the
"spokes" that were seen by the Voyager spacecraft. These
spokes have been reported by earth-based observers previous
to the Voyager flyby, notably by Steve O'Meara of
Cambridge, Mass. The only difficulty in seeing them will
be that the tilt of the rings reaches a maximum of only 17°
from edge-on this year, so that they will be smaller than
if the rings were wide open. But the spokes are certainly
within the resolving power of any telescope which can
detect Cassini's Division.
Of Saturn's many satellites (16 or more?), up to seven
can be seen in amateur telescopes. Refer to the Handbook
for orbital information on the moons. They should be
identifiable by their daily motion around the planet
Titan is the brightest and should be easy. There are 3
fairly bright ones in close orbit. Another 4 are more
challenging.
Jupiter is interesting because its appearance is never
the same. Storm patterns shift daily, as do the colors and
intensities of its bands, belts, and spots. Look for the
Great Red Spot, the largest and longest-lived storm in
Jupiter's atmosphere.
More information on the features and observability of
these and other planets can be found in the Handbook.
Recent explorations of the planets by spacecraft have
made the scientific ground-based observation of the planets
seem perhaps less useful, but for an amateur it should make
little difference. Why bother observing the planets if
spacecraft have done a much better job than earthly
telescopes? Maybe the next article, taken from the
newsletter of the Lackawanna Astronomical Society
(Scranton, Pennsylvania) will help to answer that.
-2-STARGAZERS OF THE WORLD UNITE Jo-Ann Pluciennik
Recently in the Science News someone wrote in
protesting the use of the term "amateur astronomer in
describing someone, claiming "an amateur astronomer was one
who does trivial astronomy using obsolete instruments."
This naturally resulted in a deluge of letters from irate
amateur astronomers who pointed out that the amateur
astronomer of yesterday was equivalent to the
professionals, and that even today such amateur groups as
AAVSO (variable star observers), IAUPP (photoelectric
photometry) and IOTA (occultation timers) are making a real
contribution to the science, by accumulating the sort of
data the big observatories cannot afford to devote
telescope time to.
I have to admit to being indignant myself about that
description but the responses did not hit the point I felt
most strongly about. People who do not do "serious"
observing should not be made to feel inferior to those who
do. Astronomy as a hobby should make the hobbyist happy
and enrich his or her life. There is enough in astronomy
to accommodate several catagories of enthusiasts.
If you like archeology, you can go study Stonehenge
and the medicine circles. Geology your bag? There's
meteoritics and ancient craters. Mythology? Study the
constellations. History? Look back to Tycho or only as
far back as Barnard. Philisophical? Ponder the meaning of
it all and the ideas of cosmology. Like the exotic? Read
about black holes and neutron stars. Love the outdoors?
Just stargaze with the naked eye or small binoculars and
become sensitive to the shift of the sky with the seasons
and become aware of the movements of the solar system
bodies. Photography your thing? Try to outdo the big
observatories; there's a wealth of equipment available.
Love to travel and meet people? Go to the numerous amateur
conventions and meetings. About the only thing I thought
you couldn't do with astronomy was open a booth in a flea
market, and it turns out I'm wrong about that. I hear
there was someone at the Circle Drive-In, selling views of
the sun (properly filtered, of course) for 25¢ .
Variety in life should not be discouraged, or merely
tolerated; it should be cherished. You can make a
contribution to astronomy via AAVSO or IOTA, but you don't
have to, and you shouldn't be made to feel guilty because
you don't. Only in astronomy do I find this attitude.
Most rockhound I know are not trying to identify new
-3-varieties of minerals; most birders I know are not
pretending to be ornithologists and don't feel a bit bad
about that. Hikers and backpackers are not under the
illusion that they must explore new lands.
What makes this supercilious attitude to "nonserious"
observers so hard to understand is the nature of the
hobby. I can see where professional paleontologists or
minerologists or archeologists might have a gripe if a rare
find is hacked up and destroyed by some thoughtless,
careless, or ignorant beginners, but the sky isn't harmed
by a casual glance. The stars do not get worn out by
people who are just looking for pleasure. The smudgy
galaxies don't become erased by too many people looking
them over, even with slightly out-of-focus or
out-of-alignment equipment. So why should anyone criticize
the casual observer?
Stand up for your right to enjoy your hobby as you
choose and to grow in it at your own pace. Remind yourself
that most people are attracted to astronomy by the mystery
and beauty of the night sky, not by any affinity for
physics and technology. Even the most high-achieving,
serious observer is still move by the glory of a good dark
sky. Consider this excerpt from a 1967 Life magazine
article by louden Wainwright, about George Alcock's
discovery of Nova Delphini 1967:
“When asked why he spends so much time looking at the
stars, Alcock is not able to provide much in the way of
self-illumination. A direct and active man, he is
uncomfortable with introspection and seems embarrassed with
a search for reasons. 'It's not a boring thing at all,' he
told me. 'It's beautiful, the dark sky.' Then he added:
'The stars shine like jewels in the binoculars.' In a
burst of sudden laughter he went on; 'And I'll keep
looking.' he said. 'No man has ever found two of these by
visual search.'
"Perhaps the best answer is found in his own logbook.
The neat, steady handwriting as he recorded the time and
place of the nova's appearance does not convey the
excitement he must have felt at the time. Yet a little
farther on he added another sentence, and it gave him
away. 'The star was at once recognized as a stranger,' he
wrote, and even for fools who never look up until the rain
strikes their faces, these simple words carry with them
something of the tremendous surge of joy Alcock knew in
this rare meeting of man and another world in the night
sky."
-4-THIS MONTH'S GRAZING OCCULTATION Brian Burke
Another expedition is planned to observe a lunar
grazing occultation located about 35 km east of Ottawa at
the end of this month. The site is on a secondary road 4
km south of Rockland, Ontario. It takes place on a Friday
evening and the details are:
date: April 30
time: 22:20 EDT
star: X14256
magnitude: 7.2
limb: north, dark
moon: 56% sunlit
type: favourable
The meeting place will once again be the N.R.C.
parking lot at 20:45 EDT . I expect this to be a very good
graze to observe because not only is it on the dark lint)
but it grazes about 4° away from the bright limb. You can
give me a call at 521-8856 if you would like to give this
graze a try. I am looking forward to having a large
expedition as this may be one of the better grazes we will
get for a while. Also, as always, if you have equipment to
lend, please let me know. I hope to hear from you.
* * *
THE QUIET SITE
A new list of names is being drawn up for keys to the
site. If you are truly interested in using the site,
contact one of the following members of the Quiet Site
Committee for consideration for the list:
Rolf Meier...820-5784
Rob McCallum...729-9977
Robert Dick...231-3913
The number of people on the list is restricted for
security reasons, and so only the most enthusiastic and
responsible people will be placed on the list.
Later this spring there will be a spring cleanup of
the site, in preparation for some meteor observing sessions
and star nights which we hope to hold there as the weather
permits.
-5--6-ASTRO NOTES
c/o Herzberg Institute of Astrophysics
National Research Council of Canada
100 Sussex Drive
Ottawa Canada
K 1A 0R6
TO:
MS. ROSEMARY FREEMAN CAST
NATIONAL SECRETARY
THE ROYAL ASTRON. SOC . OF CAN.
124 MERTON STREET
TORONTO, ONTARIO M4 S 2Z