AstroNotes 1982 July Vol: 21 issue 07



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The Newsletter Magazine of the Ottawa Centre of the RASC
V ol. 21, No. 7 $5.00 a year July, 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
Chairman Rolf Meier opened the meeting at 8:18 pm with
47 people in attendance, 8 of whom were non-members. With
the cleanup of the Quiet Site scheduled for the following
day, Rolf requested sane extra hands and a pick-up truck to
ready the site for a star night later on in the month. He
also reminded the group of the upcoming General Assembly,
and of instrumentation night as the theme for the next
Brian Burke was first up with some good results to
report after a successful graze expedition on April 30th.
A full breakdown of station observations ensued with the
aid of detailed charts and graphs that summarized these
observers' fine effort. It was noted that this was the
first successful graze in a long, long time, and maybe not
the last.
Yours truly was up for 57 seconds to inform the group
on the path of Comet Grigg-Skjellerup, which was bo have
passed through the constellations Leo and Cancer during the
remainder of the spring season.
Vice-Chairman Rob McCallum delivered an in-depth
dissertation on the description and function of sundials.
Rob explained a few definitions such as "noon", "solar
day", and "mean day" in order to raise an important
characteristic concerning the accuracy of these
instruments. The two greatest sources of potential
inaccuracy are the inclination of the earth's orbit to the
ecliptic, and its elliptical path around the sun.
Astrophotography coordinator Frank Roy amazed the
group once again with another dose of terrific aurora
slides taken in late April. Some interesting colours w ere
-1-noted; many colours are rarely seen, although all are
theoretically possible. Frank also reported the damage of
the IRORI antennae when they were blown down by strong
winds the previous month.
Solar coordinator Rob Dick reported a marked
decreasing trend in solar activity this past month.
According to Rob's predictions, activity should increase
this month, as the sun seems to be following a cyclic path
of activity and we are seeing a low point right now. A few
slides were presented to the group.
Lunar and planetary expert Philip Forsyth showed us
where to find the planets in May. Both Jupiter and Saturn
were at opposition in April, and together with Mars should
make for good planetary observing this month. Philip also
showed the group some of his attempts at planetary
Fred Lossing was up to show the group his R.A. axis
readout. Fred passed on some practical building hints for
anyone who wishes to build one for himself.
Rolf adjourned the meeting at 10:14 pm.
* * *
The June meeting was held in the auditorium instead of
room 3001 because of repairs to the falling plaster in our
usual meeting place.
Chairman Rolf Meier opened the meeting at 8:18 pm with
40 people in attendance, 13 of whom were non-members. Rolf
had some announcments concerning the coming Stellafane
convention, which will be held on Saturday, August 14th, on
Breezy Hill, near Springfield, Vermont. Rolf also reported
that a successful star night was held the previous month at
the Quiet Site. He also mentioned the total lunar eclipse
coming up on July 6th.
As tonight was Instrument Night, the meeting was
shortened in order to allow members to examine the various
equipment brought in by group members.
Dave Lauzon mentioned that the June Lyrids are the
next major shower and a meteor watch is planned at the
Quiet Site on the night of June 18/19.
Brian Burke spoke on occultations and on Eclipsing
Louis Krushnisky showed some constellation slides
-2-taken from within the city, including Ursa Minor, Gemini,
and many others.
Frank Roy demonstrated his Apple micro-computer. With
the help of David Vincent's software, Frank has used it to
record and display data from the radio telescope, for later
Rob Dick reported low solar activity, but keep your
eyes open and report any aurora activity.
Yours truly came up to say that Comet Grigg-Skjellerup
was much brighter than expected. It was in Ursa Minor at
magnitude 10.
Bob Barclay showed an equatorial telescope platform to
be used with large reflectors. This interesting and
compact arrangement was "driven" by a slow leak of pressure
from a hydraulic jack.
The group was then invited to examine the various
pieces of instrumentation and to ask as many questions as
The meeting was never officially adjourned, but most
people were gone by 11:20 pm.
* * *
Perhaps the most exciting activity on the sun this
last month occured on Sunday, June 6, 1982, between 11:40
and 14:45 EST. Ken Tapping called me to report a very
large burst detected by his radio telescope at 435 MHz. It
drove the pen on his chart recorder off the scale but he
estimates that its magnitude was greater than 250 S.F.U.
The pen remained off scale for 3 hours! The burst was
energetic enough to wipe out his reception of WWV for the
entire active period. Ken later reported that at a
wavelength of 2.8 cm (S-band), the signal strength was 3000
As figure 1 shows, this burst of solar activity and
subsequent flares occured during a most uninteresting
stretch of low activity when measured at radio
wavelengths. This reinforces the view that observational
programs must be continually maintained in order to catch
these events.
At visual wavelengths the sun was far from featureless. Although Sunday, June 6 was overcast, Monday was
clear. I was able to take a number of interesting
photographs of the sun in white light as well as H-alpha.
-3-I have traced 3 prints made from these photographs and they
are presented here.
The top sketch in figure 2 is the layout of the
sunspot group close to the centre of the disc. The
resolution is fair and the scale of the sketch is 2
arc-seconds per mm. There are several large spots with
many smaller ones. The penumbra (grey area) is quite
complex and extensive throughout the group.
A closer look at the top sketch, taken at 11:57 EDT,
shows a dark "whisp" about 1.5 am to the upper left of the
main spot. After recording this group in red light I
turned on the heater to the H-alpha filter. About 10
minutes later, in the light of H-alpha, I observed three
bright spots (marked as "x" on the top sketch). As I
observed these spots, a bright line arced southward, convex
to the southeast, from the most northern bright spot.
 I quickly mounted my camera, loaded with Kodak TP 2415
film. By the time I had the group centered and in focus,
the area around the initial bright spots was very bright.
At 12:09 EDT, a second picture was taken and is reproduced
in the middle sketch of figure 2. The spot which was about
1.2 cm NW of the large spot is hidden beneath the flare.
The photograph was not taken when the seeing was good so
the resolution was quite poor.
A few moments later the briqht area had grown and the
last picture was taken. The dashed lines on the lower
sketch outline bright areas which were less intense than
the core of the flare. Poor seeing conditions washed out
many of the small spots which were already difficult to see
against the H-alpha structure. The distortion of the
central spot is due to seeing conditions as atmospheric
turbulence can appear to shift features several arc-seconds
from their true positions.
Ken did not record any burst on June 7 but suggested
that the flare activity was at a low altitude and thus
below the reach of his radio telescope.
Two auroras were reported. Rolf Meier observed an
extensive display at IRO on June 9/10. Dave Lauzon saw a
display on June 11/12. It was also observed at IRO by all
those in attendance.
* * *
Don't forget about the total lunar eclipse which takes
place on July 6th. Details can be found in the Observer's
Handbook 1982.
Graze One: At Least It Was Clear
The first graze expedition of the year was made on
March 28th. Seven of us met in the N.R.C. parking lot at
18:45 EST and then left for the graze site. The graze was
to occur at 20:22 EST at a site about 35 km north of
Ottawa. We did not have any trouble finding the graze site
but from then on everything went down hill.
Since the star's magnitude was 8.1 and was being
grazed on the bright north limb, the graze was classified
as marginal. One favourable point was that the moon was
only 16% sunlit.
There were four stations established, covering a
distance of about 3 km. Brian Stokoe and I set up just off
the road about 100 metres south of the graze line. All
other stations were south of us. The major problem was
that the star was just too dim to see near the bright
limb. We thought it would be a great idea to guide the
3.5-inch Questar manually and use its power supply bo drive
the tape recorder. We feared that the batteries in the
recorder would not last long in the cool temperature.
However, I discovered to my surprise that the power supply
to drive a small Questar is simply not designed to drive a
tape recorder at the proper speed. Thus the playback speed
is about 2.5 times the recorded speed, and our voices are
reduced to high-speed squeaks.
Another statical had difficulty in seeing the star in
the moon's glare. That station observed a total
occultation and only observed the reappearance after the
star was well clear of the limb. A third station lost the
star completely in the glare, and the fourth station lost
the moon when their Astroscan was accidentally moved.
Meanwhile, back at our station, Brian and I were glad
that the fiercely-barking dogs were down the road until we
turned around and saw a dog sitting a few feet behind us.
Finally, the dog got bored and walked away.
It appeared that the time of graze given in the
predictions was way off when Brian finally observed a total
occultation many minutes after the predicted time.
We packed it in and headed down the road to find out
what the other stations observed. After briefly discussing
the total occultation that John and Robin Molson had
observed, Brian and I concluded that graze predictions will
appear to be wrong if you observe the wrong star! Problems
for Robin and John continued when their car battery died,
but fortunately they had a backup one which was being used
-7-to drive their equipment.
So, although everything seemed to go wrong, at least
the sky was clear.
Graze Tw o: Multiple Events Observed!
Although the previous month's graze had a few
problems, nine of us met in the N.R.C. parking lot at 20:45
EDT on April 30th for another graze expedition. This graze
was classified as favourable, with a 7.2-magnitude star
grazing on the dark north limb and the moon 56% sunlit.
The graze site was located 4 km south of Rockland, Ontario.
After about a 30-minute drive, we arrived at the graze
site where a few natives of Rockland, headed by Mrs. Bea
MacTavish, were waiting for us. Mrs. MacTavish is a member
of the Ottawa Centre who lives in Rockland and had
contacted me after reading about the graze in Astronotes.
Since we had arrived late, setting up was very
rushed. We used the location where a creek ran under the
road as our starting point. The graze line, or predicted
limit, was within 50 metres of the creek. Brian Stokoe was
stationed 500 meteres east of the creek, Fred Lossing and
John Horwood were at the creek, Rob Dick and Louis
Krushnisky were 500 metres west of the creek, Rolf Meier
and Rob McCallum were 1000 metres west, and Jim Zillinsky
and I were 1500 metres west.
Brian Stokoe, Fred Lossing, and John Horwood did not
observe any events, but the other three stations observed
many events. The observations are summarized on the
diagram on page 9. All times were corrected for reaction
time. The station numbers are shown on the left in the
diagram. The time of central graze was predicted to be at
22:20:14 EDT or 02:20:14 UT on May 1st. It appears from
the diagram that the graze line had shifted north by at
least 0.5". The profile shown in the diagram is from the
predictions. It should be mentioned that the sky
conditions were not perfect, but rather there were some
high clouds and the cloud cover increased later in the
night. The "events" that Jim "observed" long after the
time of central graze may have been caused by the
increasing cloud cover.
Therefore, after many attempts, we finally had a graze
in which more than one station observed events. I hope for
future grazes we can get more observers and thus more
stations. I should soon be receiving the predictions for
the second half of 1982.
* * *
The following parts are available from Bob Barclay,
3609 Dompatrick Road, Ottawa, K1V 9P4.
An attempt to observe the June Lyrids on June 18 was
unfortunately clouded out. Stay tuned at Observer's Group
meetings for news of other activities planned at the site.
* * *
Articles for the August issue of Astronotes are due by
July 23rd.
c / o Herzberg Institute of Astrophysics
National Research Council of Canada
100 Sussex Drive
Ottawa Canada
K 1A 0R6