AstroNotes 1981 June Vol: 20 issue 06

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ASTRONOTES
ISSN 0048-8682
The Newsletter Magazine of the Ottawa Centre of the RASC
Vol. 20, No. 5
$5.00 a year
June, 1981
Editor........Rolf Mei er. ......4-A Arnold D r ...... 820-5784
Addresses.... Art Fraser.......11-860 Cahill Dr... 225-3082
Circulation...Barry Matthews... 2237 Iris St....... 225-6600
OBSERVER'S GROUP MEETING - MAY 1
Susan Argue
Brian Burke opened the meeting at 8:05 pm with the
preliminaries.
Mentioned were activities in Ottawa during
May, the categories for the General Assembly, and the
long-awaited Observer's Manual at $4 for members and $6 for
non-members.
In attendance were 56 people, 48 of whom were
members.
Robin Molson was up first with the news that the
secondary mirror for the 16-inch was re-aluminized and that
the mesh for the radio telescope had been picked up.
He
also mentioned a small mishap that occured at IRO during
the time of high winds - the outhouse fell over.
Rob Dick was up next with news of the April 12/13
aurora.
He had some slides of sunspots taken just before
and after April 10.
The latter had sunspots that were
lighter. There was a fair amount of activity on the Friday
before the aurora, and the aurora itself on the Sunday
night had shades of green and red.
The slides showed the
aurora around Jupiter, Saturn, and the moon.
The radio
telescopes of Ken Tapping and Jim Zillinsky showed an
increase of activity at the appropriate time. There were a
few slides of some bright complex groups of sunspots, taken
on April 21.
The question of why Herschel discovered Uranus was
asked and answered by a summary of his life, by Barry
Matthews.
Basically, Herschel went from a very poor educa­
tion and poverty to fame by teaching himself English,
music, math, and astronomy.
He devised a new mounting so
that a single person could handle a telescope and he kept a
very detailed and well-organised log of his observations.
-1-What he first thought to be a comet turned out to be
"George's Star", later named Uranus.
He was given a
position, at 200 pounds a year, to show stellar objects to
the royal family.
Ted Bean was up next with slides that showed 3
different methods of preparing a pitch lap.
Each set of
slides outlined the materials required and other details.
Frank Roy gave a review on hypersensitized film.
His
slides, mainly on Fuji 400, included several 15—minute
exposures of galaxies, some in Leo and Virgo. On slide had
at least 8 galaxies.
There were several exposures of M 51
shown for comparison. The hypersensitised exposures showed
much more detail.
Also included were slides of Berenices
Hair, the moon, and a 25— slide series of the April 17
aurora. A nice shot of the fallen outhouse at IRO was also
shown.
Dave Paterson was lucky enough to gain a press pass
for the Space Shuttle launch.
He had a series of slides
that ranged from close up to the Columbia (from the tour
for the press) to the small speck she became after launch.
Brian Burke had a report on the April 9 graze.
Details are in last month's issue of Astronotes.
The meeting was adjourned at 10:12 pm.
* * *
RADIO TELESCOPE PICKS DP HERCULES A
Frank Roy
Recently, the Indian River Observatory Radio Inter­
ferometer detected the radio source Hercules A, listed as
3C 348 in the 3rd Cambridge catalog of radio sources.
So
far this is the sixth radio source picked up with our radio
interferometer after the sun, Cas A, Cyg A, Tau A, and
Vir A.
It is also the weakest source so far received. At
178 MHz it is listed at 325 flux units (1 fu = 10- 26 W m — 2
Hz- 1 ) and is approximately 200 fu at our frequency of 238.5
MHz.
Hercules A is a member of a remote cluster of galaxies
and is one of the brightest radio sources in the sky. With
a time constant of 10 seconds, Hercules A was about equal
to the noise in our system.
There are several other
sources that we will soon at to our list. Most of them are
supernova remnants and radio galaxies.
* * *
-2-SOLAR DISC NUMBER 2
Robert Dick
As promised last month, on these pages is
the template for the sun when its pole is
tilted by 1° (Beta = 1°). This will be
useful for part of June. Future
issues will present discs of
other polar inclina
t
i
o
n
s
.
-3 -
- 4 --5-SOLAR ACTIVITY OF APRIL
Robert Dick
The sun was quite active throughout April, as the
hemisphere that produced the activity in March rolled by
again. A plot of the radio data obtained by Ken Tapping at
435 MHz and Jim Zillinsky at 230 MHz accompanies this
article in figure 1.
The increased activity of the sun during this month is
primarily due to short duration bursts.
The data at 230
MHz indicates a moderately enhanced background level with
almost daily bursts which produced levels greatly in excess
of the limiting scale of figure 1.
It should be pointed
out that both Tapping and Zillinsky record the sun only a
few hours on either side of noon.
Unfortunately, in
Tappings absence (he is currently in Europe), we do not
have 435 MHz data to compare with Zillinsy’s observations.
Two instances of aurora have been reported to me.
A
great display took place on April 12/13, and Frank Roy
reported another on April 25/26. Louis Krushnisky reported
that the large group that was on the disc during the days
preceding April 12 was still on the solar disc in the
north-west quadrant and consisted of a complex of large and
small spots.
Due to the poor seeing in the beginning May, there
have been no reports or photographs of large sunspots so
far.
If any readers have observed the sun during this
time, I would like to hear from them.
* * *
PLANNED SAVINGS IN ASTRONOTES
Robin Molson wishes to pass on a few suggestions for
reducing
the
cost
of
producing
and
distributing
Astronotes.
1) Reduce the number of copies per month from 300 to
240, by a purge of names of former members.
2) A greater reliance on members picking up copies at
meetings.
3)
An increase in revenue through an increase in
membership.
4) Applying 2nd class mailing rates.
These suggestions are part of a report prepared by the
finance committee.
* * *
-6-ASTRO NOTES
TO
MS. ROSEMARY FREEMAN
CAST
NAT I ONAL S E C R E T A R Y
THE ROYAL ASTRON. SOC . OF CAN.
1 2 4 MERTON S T R E E T
TORONTO, ONTARI O
M4S 2
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