Mississauga Astronomical Society

Special Public Astronomy Lecture

Day:                Sunday, Sept. 26, 2004

Chair:         Randy Attwood

Speakers:        Brian Cheaney 

                         Special guest:   Terrence Dickinson

 The Sky at Night

Brian Cheaney illustrated the night sky and objects visible at the present time. The planets were each described in turn as real worlds and their locations pointed out.  Specific attention was given to Mars and Saturn and the current space missions to these planets. Brian explained the lunar phases and the reason for observing features on the terminator. He described the rationale of observing deep sky objects during the dark of the new moon.  The Hercules cluster M13 and Andromeda galaxy were highlighted. Many questions were entertained after his interesting talk.

A Brief Tour of the Universe

Special Presentation by Terrence Dickinson

Randy Attwood stated that the presentation was co-sponsored by the Mississauga Astronomical Society and the University of Toronto at Mississauga. Randy gave a short history of the society, of the R.A.S.C. and its many branches, and of the public outreach program of the society. He invited members of the public to join the society.

Randy introduced and thanked Dr. Ulrich Krull, Professor of Analytic Chemistry for providing the venue for this meeting and other meetings of the society. Dr. Krull spoke about the university and welcomed the public to the lecture.

Randy then introduced the main presenter. Terrence Dickinson is a prolific writer, having written 14 books especially his bestseller “Nightwatch” which is the essential guidebook to astronomy. He is an astrophotographer, observer and popularizer of astronomy. Terrence was awarded the coveted Klumpke Award of the Astronomical Society of the Pacific in 1996; he has an asteroid named after him (fortunately not an Earth-crosser), he has received the Order of Canada. He is editor of the journal “Skywatch” and writes the astronomy column for the Toronto Star.

Terrence started off by showing images of the sky taken from his dark site near Kingston, Ontario, including a conjunction of the Moon and Venus, constellations and auroras. Terrence emphasized that the term “amateur astronomer” should be modified into “astronomy enthusiast” as more and more people get into the hobby with all degree of passion and interest.  The largest astronomy gathering in Canada, Starfest, had 500 telescopes. Beginners can begin with binoculars for observing; in fact, binoculars are used by astronomers of all skill levels, and are best for certain objects such as large comets (e.g. Hale-Bopp). 

Enthusiasts can easily image the sky including deep sky objects such as the Beehive Cluster with current SLR digital cameras. Auroras are also a good subject for astroimaging. Unfortunately, the glow of city lights prevents all but the brightest auroras from being seen. An example of very poor lighting at a truck stop on Hwy. 416 was shown. Satellite imagery now shows that the problem of light pollution is worldwide. For deep sky observing one should at least try to get to the edge of the light pollution. Terrence showed examples of a dark sky by showing nebulosity in the Milky Way, specifically the “dark horse” north of Scorpius. The epitomy for dark skies is the magnificent sky of the Australian countryside with the brilliant Milky Way overhead.  

Using children to represent the inner planets, Terrence showed how to build a scale model of the solar system, our local part of the galaxy, and the universe at large. With the sun being the size of a golfball, the inner planets fit into the auditorium and the nearest star to our Sun (also golfball size) was in Winnipeg. He emphasized the immensity of the universe. If a truckful of sand represented the stars of the galaxy, a thimbleful would contain those visible to us. The train analogy involves a hoppercar full of sand, representing all the stars in a galaxy; with one car going by every second, it would take 3 years for all the “galaxies” to pass the observer at the railway crossing.  Finally, Terrence described the universe as cubes with each one longer than the previous by a power of 100. As the cubes increased in size, he described the objects that would be contained in them.  He described lunar eclipses, observations of Mars including Percival Lowell’s canals, Cassini images of Jupiter and Saturn, the moon Phoebe, nebulae and star forming regions. He suggested that the striking beauty of the images may be due to the fact that we are in fact products of  the same “starstuff” as in the images. Finally he showed images of galaxies and galaxy collisions and the Hubble Ultra Deep Field, with its 3-D quality. With the universe now believed to be over 13 billion years old, we are finally looking at its visible edge.

Terence finished his presentation by talking about digital photography. He stated that the Canon 20D is the most sensitive digital camera for astroimaging. He showed a 15 minute exposure of the Andromeda galaxy, the Eagle Nebula  and Cat’s Eye nebula. Digital imaging, with its ease and powerful software has democratized astrophotography, wherein anyone can take pictures of the sky.

After the presentation, Terence answered questions and spend a long time signing copies of his books which were up for sale.

 Submitted by Chris Malicki, Secretary  Chris Malicki, Secretary                               back to M.A.S. meeting reports page
Mississauga Astronomical Society