Mississauga Astronomical Society

Thirtyfirst Meeting

Speaker’s’ Night

Day:                Friday, November 26, 2004

Speaker:     Dr. John Percy  - guest speaker

Clear Sky Clock

Randy Attwood showed the Clear Sky Clock, available on the internet and via a link from the M.A.S website, with its various and new features. The M.A.S. has decided o help with sponsorship of the site. Randy also discussed the recent Council Meeting and discussions about plans to become an RASC centre, insurance liability etc.

Citizen Science – How you Can Help Unlock Secrets of the Universe

Dr. John Percy, professor of astronomy and astrophysics at the University of Toronto, researcher of variable stars, astronomy educator at all levels, winner of awards, past president of the Royal Astronomical Society of Canada, and former editor of the Observer’s Handbook, and our host at the Mississauga campus of U of T gave a compelling talk about amateur astronomers helping with research and furthering  knowledge of astronomy.  

Dr. Percy suggested that we should not be called amateur astronomers but rather citizen scientists. An amateur loves astronomy and cultivates it as a hobby, and does it with a high degree of skill without pay. A larger group of recreational sky observers appreciate the beauty of the sky; a lesser number commit time and energy with discipline, and follow procedures. The smallest number, the masters, have the satisfaction of contributing to research. Masters image asteroids, planets, variable stars; or they contribute to imaging techniques, computing, robotic telescopes etc. Almost every amateur astronomer can make a contribution by increasing public awareness in astronomy, improve scientific literacy in general. We should also support teachers who now have astronomy in the curriculum but often do not have the knowledge to teach it properly. The astronomical community has many societies, clubs, science teachers associations, government and the problem is to get these to work together. The Canadian Astronomy Association supports education in schools and outreach.

Citizen scientists can do various activities in astronomy. Sunspot measurements co-ordinated by the the American Association of Variable Star Observers (AAVSO) supply data used by professionals. Meteor counting in a systematic way helps scientists measure meteor streams in space. Occultation timings co-ordinated by IOTA allow a group of people to measure asteroid dimensions.

The best example of science in astronomy is observation of variable stars. The AAVSO, founded in 1911 (website at http://www.aavso.org/) is the most advanced organization which exists to co-ordinate, evaluate, process, organize and archive variable stars. A total of 11 million observations have been submitted to the organization since its founding and 360,000 now per year. Over 1,000 professional requests per year are now made to the AAVSO especially because of the need for nova and explosive star data which can be monitored by amateurs.

The AAVSO is also very active in education with student observing projects. As an example, Dr. Percy  asked the audience to estimate the magnitudes of delta Cephei and W Cygni. As homework, students can monitor a star like delta Cephei, draw a light curve and do a statistical analysis of their observations. By looking at a light curve of the star over many years, an increase in the period can be ascertained compatible with an increased diameter and evolution.

In the past few years, improvements in computer and telescope quality and prices, and the advent of the internet and CCD cameras allow amateurs to image objects in a way that a professional observatory could do 30 years ago. The Centre for Backyard Astrophysics (CBA) advocates photometry of rapidly variable stars. The visual afterglow of a gamma ray burst and the detection of an extrasolar planet transit are now within limits of detection by amateurs.

Dr. Percy then described his own research on red giant stars. Simple physical principles can explain the structure of a star as the balance between gravity and the outward pressure produced by nuclear fusion. Properties of the sun and other stars at various depths can be expressed by equations. Models can be tested by observations of modes of vibration, neutrino emission etc. Red giants are interesting to study because they are common, extreme in size and luminance, complicated; in addition the sun will become a red giant in the future. Students doing theses, high school students, summer students with NSERC grants, data from robotic telescopes in Arizona and data from amateurs such as R. Thompson all contribute to the research on these stars. Dr. Percy showed light curves for a number of stars, and he described the pulsations of these red giants. Computer simulations of the most famous of these, Mira, shows what the surface might look like. Pulsations produce shock waves that send material into space leaving the stripped core of the star. 

The American Astronomical Society at http://www.aas.org/wgpac/ encourages professional/amateur collaboration in research. The Ontario Science Centre also has list of activities that amateurs can be involved with.including documentation of light pollution. Dr. Percy strongly encouraged the audience to get involved. Paul Brandon thanked him on behalf of the M.A.S. for such an interesting presentation.

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