April 27th was the 20th anniversary of the first comet found in Canada by our own Rolf Meier. He now has four comets to his name. "Well done Rolf!" All of the comets were discovered using the centre's 16" telescope.
Tonight's first speaker, Paul Comision (OG Solar Coordinator) added .a few comments about daytime observations made during the demonstrations at the museum. Doug Luoma and Karen Edmonds showed Venus, and Paul was able to show the "Sol" spot! (My father's funny - it should be sole sun spot.) The talk tonight was taken from an article in Sky and Telescope (June 1998 p.19), "Supernovae Suggest an Accelerating Universe." As background to the article Paul described the current method for measuring the size of the universe using Cepheid variable stars. New measurements using supernovae are proving to be more accurate The measurements appear to show the universe is expanding at an accelerating rate. The light from supernovae is travelling 20%-30% faster than expected. It is expected that in a billion years or so this burst of acceleration will happen again. As with any new method there is the possibility of errors. Paul pointed out that during a recent Discovery Canada program an astronomer from Rochester University stated that the universe was shrinking! Who is right? Time will tell!
When asked about sunspot activity, Paul responded all was well now with two clusters of spots instead of one spot on the previous weekend.
Carmen Rush ( OG Historian) was next up and started by showing a sketch of Johannes Kepler, the subject of this month's talk. A previous talk had focused on Kepler's academic achievements; tonight's would show a more colourful side of his character. Kepler was born on Dec. 27, 1571 in the town of Weil der Stadt, Germany. His mother was raised by her aunt who was burned at the stake, accused of witchcraft. Later Kepler's mother was accused of witchcraft, but was acquitted after a two-year court trial and a skillful defence by Kepler. Kepler nearly died at the age of three from smallpox, from which he never fully recovered. After seeing a comet for the first time at the age of six Kepler was determined to become an astronomer. After graduating from university he began teaching but this did not work out well. During this time he wrote his first book, Cosmic Mystery (1595). Although the data was not very accurate the book caught the attention of Danish astronomer Tycho Brahe. Tycho was impressed with Kepler's mathematical abilities, and invited him to join his team of astronomers in Prague. Tycho was well connected to the King of Denmark and was able to have almost anything he wanted, including a private island with castle and servants. Kepler joined Tycho in 1600. Kepler published the first two laws of planetary motion in 1609 in a book entitled The New Astronomy. Ten years later, Kepler established his third principle of planetary motion, which related the time a planet takes to complete an orbit of the Sun and the average distance of that planet away from the Sun. Carmen continued with a summary of the book called The Dream, which credits Kepler as the first science fiction writer. Johannes Kepler died after an acute illness in Regensberg, Germany, on Nov. 15, 1630, aged 58 years.
Glenn LeDrew (Comet Coordinator) started his talk with follow-on information about his investigation into the mean motion of stars and star groups. Last month Glenn had described the results of a computer program that had been manually loaded with a few hundred reference star coordinates. The results had been rather random. Since then he had been able to use a program to input data directly from other databases and stars within 25 parsecs. This resulted in just over 2,000 stars being selected which had the right mean motion. The print-out showed the movement of the selected stars relative to Earth on a map using the Galactic Coordinate System. The stars tend to converge at two points. A first concentration in the region of Orion covered approximately a 60-degree field; the second was near Scorpius. Using the larger database provides much clearer resulting concentrations.
Glenn continued with the first in a series of slides. These showed the construction details of a pair of 5" f/5 binoculars which he had built for a member of the Centre. The next set of slides showed the location and area views of a new observing site NW of Calabogie. This site has a bed and breakfast (run by the owner) and is accessible throughout the winter. It is far enough away from urban centres and provides a great place to observe. Permission has been obtained for other members of the Ottawa Centre to use the facilities. The last series showed a recent training course at the IRO.
Linda Meier was next up to remind everyone of the up-coming public star party on May 23 at the Diefenbunker (West Carleton Township Library) in Carp.
The OG's Lunar and Planetary coordinator Doug Luoma showed a number of slides, an all-sky globe, a 40-degree halo around the Moon, Venus and Orion, conjunction of the Moon, Venus, Mars and Jupiter (November 1995, 135mm f/4 lens ISO 100 film with a 6-second exposure), the recent conjunction of Moon, Venus and Jupiter (200mm f4 lens, ISO 100 film and 4-second exposure). Following this last conjunction observers could have also looked for the planets during daylight. Doug also reported another conjunction of the Moon, Jupiter and Venus on the morning of May 23. Saturn and Venus will be only 0.7 degrees apart.
My editor, Brian McCullough, was next to speak. He introduced Jack Scrimgeour who attended one of Brian's astronomy courses. Jack described how he solved a problem of how to mount and point binoculars on a tripod. He constructed a simple "sighting stick" attached to the mount on the tripod, which he demonstrated at the meeting. This allowed him to orient the binoculars very easily. The concentric circles on the arm provided a simple way to point toward the correct area of the sky.
Brian continued with a demonstration of another useful device. We all could use another hand while observing, one to hold the light, one to hold the map, and the other to operate the telescope. During a visit to Le Baron's sport and camping supplies, Brian found a caver's "headlamp" which he modified with a red filter. Brian showed us how he operated the new device. Instead of placing the lamp on his head, he slides the lamp completely over his head and the lamp now rests on his chest. This way the light falls downward in an ideal orientation for reviewing a map, sketching, etc.
Paul Miil was next up and his talk was about the Algonquin Radio Observatory (ARO). Following a discussion with other members during a visit to IRO, Paul agreed to contact the current operators of the ARO to find out if members of the RASC could use the facilities. The ARO was closed in 1987 due to budget cutbacks. A letter was sent to the Geodetic Survey department of the federal government. The reply states that the ARO is no longer closed and has been actively operating as a part of the Very Long Base Interferometer network. However the ARO would look into the possibility of allowing RASC members to use the facilities. Any request to use the facilities would need to provide details of the type of activities planned. The department indicated the possibility of a charge being levied for the use of the ARO. Paul asked for names of anyone who was interested in undertaking observations at ARO or who would be interested in other radio astronomy activities.
The final speaker this month was my dad, Peter Williams, the 1998 Astronomy Day coordinator. Peter provided a summary of the Astronomy Week activities. He began by thanking all of the volunteers who helped to make this year's events a success. The public star party at the museum featured more than 15 telescopes (all the way to a 16" Dobsonian) and binoculars for the public to view the heavens. The Ottawa Centre also hosted a large exhibit at St. Laurent Centre. It included a mirror-grinding demonstration, astronomical software, telescope demonstrations (home-built 10" Dobsonian, 4" refractor, 5" Schmidt, 6" reflector and binoculars and observing chair), children's craft table, exhibit of astrophotographs of the solar system, meteorite samples and explanations. Hundreds of visitors viewed the exhibits, consumed more than 3,000 handouts, brochures and information sheets and kept the volunteers very busy throughout the day. The Ottawa Centre would like to thank Jim Cummings of Cummings Mitchell for the loan of the Skyline display booth, Atlantic Electronics for the video equipment and St. Laurent Centre for the use of Centre Court and for the use of equipment during the day.
Gary closed the meeting reminding people of the after meeting at Kelsey's. Refreshments were served in the museum lobby courtesy of Anne and Art Fraser.