Mississauga
Astronomical Society
Tenth Meeting
Members’ Night
Day: 8 p.m. Friday, November 7,
2003
Speakers:
Randy Attwood
Brian
Cheaney
Chris
Malicki
Ian
McGregor
Phil
Mozel
Introduction
and welcome
Phil Mozel, the new meeting co-ordinator,
chaired
the meeting and asked members of the M.A.S. to make presentations at
members’
nights.
Starry
Night Pro and M.A.S.
Website
Randy Attwood
demonstrated tomorrow’s
total lunar eclipse on the Starry Night Pro. The computer program
showed the appearance
of the eclipse from viewpoints of the Moon, the Sun, and the Earth
(from Mississauga). He then gave us a tour of the Mississauga
Astronomical Society website at http://www.mississaugaastronomicalsociety.ca/. The website, which will be updated, was
set
up by Brian Cheaney. One of the most useful links is to the Mississauga Clear Sky Clock which gives quite
accurate
predictions on cloud cover, transparency, seeing.
Other links to
aurora pages, SOHO
and MOST spacecraft, Astro Picture of the Day were illustrated. The
M.A.S.
website is and will become a valuable resource to astronomers in Mississauga.
The Sky
Tonight and
Binocular Stand
Brian Cheaney continued his monthly talks
about
events in the sky and objects to see. He illustrated how the
constellation of
Cassiopeia can conveniently be used to find a number of objects,
specifically
M31 (Andromeda Galaxy), the double cluster NGC 884 and 869, NGC 457
(which
looks like the character ET), and others. He described starhopping
using a
telrad finder to find more difficult objects such as NGC 7662.
Brian then went on to demonstrate a binocular
stand
and holder that he has constructed using crutches as legs and either
aluminum
tubing or wood for the bars. 65 Messier objects are visible with
binoculars,
but views are unsteady and tiring when heavier binoculars are handheld
after 5
seconds. The binocular stand, one of seven that he has constructed,
greatly
enhances viewing, and is especially good at public observing sessions
because
the allignment stays the same even after adjustment to the height of
the observer
(child vs. adult). Plans for construction were available, and most
members in
the audience examined the stand with great interest during the
intermission.
Five
Lunar Eclipses
In preparation to tomorrow’s eclipse,
Chris
Malicki
showed photos taken of 5 different lunar eclipses that he has observed
over the
years. The pictures, taken with a
Celestron 8, and Meade 10” at prime focus showed both partial and total
phases
at differing exposure times. One was able to see how different exposure
times
can enhance either the umbral phase
during partial or total eclipse, the deep penumbral phase or the
shallow
penumbral phase. Pictures were shown of the deep partial eclipse of Mar. 23,
1997 with a magnitude
of 0.9, the colourful eclipse of Jan. 20, 2000, the partial of July 16/17, 1981, the
partial of June 25, 1983, and the total of Aug. 16,
1989. He also
described the Danjon scale for eclipse darkness and
encouraged members to estimate the value for tomorrow’s eclipse.
Eclipses
I have Known and
Loved
Ian McGregor spoke about partial and
total
lunar
eclipses that have been visible from Ontario from 1986 to 2008, noting
those that are especially good for visibility (although I wonder why 17
August, 1989 doesn’t
have a star beside it). He described the
Saros Cycle for eclipse repetition and showed how the eclipse of Nov. 8,
2003
of Cycle 126
is the 45th of a total of 72 eclipses, the last one being on
Oct. 28, 1985. That one, however was visible is China, 1/3 of an earth rotation
apart. It takes 3 Saros cycles for an eclipse to return to the same
earth
hemisphere. Last May’s eclipse, on the
other hand is the 55th of 84 lunar eclipses of Saros cycle
121. Next
Oct. 28, 2004 will be the 19th
of 72 eclipses of Cycle 136. The Mayas
knew about the eclipse cycle as is evident from their Dresden codex.
Lunar
Eclipses
Phil Mozel showed slides of several
lunar
eclipses
that he has photographed. He has used a number of lenses from 100mm to
a C8 at
2000mm. For comparison reasons from one eclipse to the next, he uses
the same
film. He frames the eclipsed moon behind foreground objects in the
short focal
length exposures. He described his technique of bracketing exposures to
bring
out different aspects of the eclipsed moon. This method was especially
well
shown in his images of the eclipse of July 1982. His photography has
brought
him some measure of fame especially when his Nov. 1993 lunar eclipse
shot made
the cover of Season’s Magazine.
Phil then told the story of the siege of
the
city of
Syracuse on the island of Sicily by the Athenian navy in
413B.C. A lunar eclipse on Aug. 27 of
that year convinced the soothsayers to delay the departure of the
vessels from Syracuse for a month with the result
that the Athenian navy was utterly destroyed. Phil used this as an
example of
how a lunar eclipse changed the course of history: It was the “greatest
effect
in history that an eclipse has ever had.”
Submitted by Chris Malicki,
Secretary
Chris
Malicki, Secretary
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Mississauga
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