Star Points for June, 2003; by Curtis Roelle Amateur Astronomers Wait Out Clouds Last month's weather was uncooperative preventing most people in our region from observing the special events of the month such as the total lunar eclipse. Although it was not mentioned in this column, another special event occurred on May 7 when the planet mercury transited the face of the sun. I missed the transit because of clouds at home. However, Westminster Astronomical Society member Stephen Reisinger of Catonsville viewed the transit from Catonsville Community College. According to Stephen clouds obscured the sun at first, but then they disappeared. "Mercury was quite small," according to Stephen, "but I was able to see Mercury for about the last 5-7 minutes of the transit." Weather permitting the eclipse and transit were visible to everyone on the side of the earth facing the appropriate direction. There was one astronomical event in May visible only in a narrow region which included parts of Westminster. This was the "grazing occultation" of a bright star in Virgo by the moon on the evening of Mother's Day. In a nutshell, as the moon orbits the earth it will occasionally pass in front of a star, blocking its light. This is just what happened on Mothers Day. However, for lucky observers in a narrow ribbon of land a mile wide and stretching from Assateague Island through the Great Lakes, the star appeared to pass along - or "graze" - the darkened edge of the moon, winking on and off as lunar mountains blocked and unblocked the star. Observations and timings of these events by observers across the path are useful for mapping regions of the lunar profile that are too close to the poles to be mapped by spacecraft, and too near to the edge to be mapped telescopically. Knowledge of the lunar profile has further applications such as helping to determine the extent to which the sun may be shrinking or expanding. An expedition organized by the International Occultation Timing Association set up observing stations at locations around the Carroll County airport from which the event was observed. The stations were manned by a number of volunteers, many from the Westminster Astronomical Society. The clear night permitted observers to time and videotape the event from various vantage points. The data is still being analyzed. It's true that when it comes to astronomy real science can be done by amateurs using equipment that won't break the bank. In amateur astronomer there is power in numbers. Many small telescopes can do what a single large professional instrument cannot accomplish. For example, amateurs can monitor the changing brightness of "variable" stars. If it is cloudy at one site, somebody else at a clear site can gather the data. With enough amateur astronomers around the world a star can be monitored 24 hours a day. When each observer monitors many different stars you can begin to see what power in numbers means. Amateur astronomers also conduct observations that have helped to determine the shape of certain asteroids. Other amateurs search for comets and novae in our galaxy or supernovae in galaxies that are far away. These are just some of the areas in which amateur astronomers are actively helping solve the mysteries of the solar system and the universe. Some amateurs have mastered the art of astrophotography, either on film or digitally. But for the most part the amateur astronomer is basically a sight seer. Like their fellow humans they are passengers of the earth as it journeys around the sun, which in turn circles lazily around the core of our Milky Way galaxy. The only difference is that amateur astronomers have their windows rolled down.