Mississauga Astronomical Society
                                                                    Eleventh Meeting
                                                                    Speakers’ Night

 Day:           8 p.m.   Friday, November 21, 2003      

Speakers:     Dr. Kieran A. Carroll, Dynacon Inc. -  Guest Speaker
                          Guy Nason

First In-Orbit Results from MOST, Canada’s First Space Telescope

 Dr. Kieran A Carroll, PhD, aerospace engineer at Dynacon Inc. of Mississauga was the guest speaker.  Dr. Carroll is the chief designer of the Microvariability and Oscillations of STars spacecraft, known also as MOST, or affectionately as Canada’s “Humble Space Telescope”. MOST is Canada’s first science satellite in over 30 years and also Canada’s first microsatellite.

 Canada’s Space program, funded by the Canadian Space Agency (CSA), began in the 1960’s with the Alouette and ISIS satellites. By the 1980’s it was concerned with the space shuttle, Canadarm and astronaut program.   In the 1990’s various earth imaging satellites such as MSAT, radarsat, WINDII and others were launched. In addition, Canadian space instruments flew on various satellites but no purely Canadian space satellite was launched.  Finally in 1996 the CSA funded the small payloads program. The MOST proposal won out over 11 other competitors in August of 1998 both because of its innovative science and because of it stayed within the difficult budget constraint of $10 million, including launch.

 Dr. Carroll explained in great detail the history of the MOST project, the principal investigator Slavek Rucinski who studies variable stars and astroseismology, and the MOST team (UBC, U of T, Dynacom, CSA funding). The satellite contains a Maksutov telescope, Fabry lenslets, a custom star tracker and specialized microreaction wheels (motorized flywheels).  He described the various systems of the satellite, the solar panels, flywheels, the focal plane and CCD’s, the attitude pointing systems and electronics.

 As a microsatellite, MOST had very challenging constraints such as a mass limit of 50kg a shape dictated by the launch vehicle and the cost as noted above.  MOST was initially supposed to be launched in 2001 as a hitchhiker to a Radarsat, but that project was repeatedly delayed and the actual launch finally took place from Plesetsk, Siberia on a Russian Rockot together with a number of other satellites on June 30, 2003.  After  months of commissioning and calibration, first light came on July 29 with a 10^th mag star in Capricornus and finally the first Fabry image of 51 Pegasi.

The primary science of MOST involves observation of stars with the ultraprecise photometry necessary to detect vibration modes, the ultrafine splitting of spectral lines.

With its extremely accurate pointing accuracy of less than 25 arcsec. MOST is an ultraprecise photometer able to detect changes in light output of 1ppm in stars and thus is able to detect the  fine mode splitting of the lines. No other instrument in space other than Hubble has this photometric capability. However, the HST, although also a precise photometer, is unable to target a star for the length of time that the MOST can.  Dr. Carroll described the metal poor subdwarfs, or population 1 stars, which contain almost only hydrogen and helium and as such are among the oldest in the universe. They are also predicted to exhibit astroseismological variations sensitive to age dependent core composition. Study of these stars by MOST can help put a best “before” date on the universe. MOST should also be able to detect extrasolar planets by their phase effect (something never achieved before). A good candidate star for this is tau Bootes. 

 Finally, Dr. Carroll showed the first science data for MOST.  This was a light curve for the beta Cephei variable star HD 16582 which shows a 0.7 millihertz vibration frequency never before seen with this star. The results should be published soon.

 After a number of questions from the audience, Ian McGregor thanked Dr. Carroll for his extremely detailed and interesting talk about this Canadian space telescope.

 
Asteroid Occultation visible from the GTA

 Guy Nason from the Toronto Centre RASC described an upcoming occultation of an 8.2 magnitude star in Pisces by the asteroid (757) Portlandia on Dec. 7 at 6:00pm. The occultation, described at the website http://www.asteroidccultation.com  is especially suited for observers in the GTA because southern Ontario is virtually the only place from which this event is observable. In addition, the Oshawa to St. Catharines horseshoe area of western Lake Ontario provides a near perfect observing cord for measuring the 32km wide asteroid. He urged the M.A.S. members to observe this event either with taperecorder and time signals, or with videotaping of the occultation, and contribute to measuring this asteroid.  

 
Announcements

 Randy Attwood announced that the first meeting of the M.A.S.  executive had been held. A new fee schedule has been established for the year 2004 as well as new initiatives of the organization.

 Three students from the U of T Astronomy and Space Exploration Society spoke about their organization and asked the M.A.S. to help them petition the Canadian government to increase funding for space exploration. Their website is at  http://www.marssociety.ca.