Colorado Astronomy Day with the Denver Astronomical Society

Celebrating Colorado Astronomy Day, Saturday, October 01, 2011, the Denver Astronomical Society and Denver Museum of Nature & Science threw a Star Party of the greatest magnitude. Hosting a day of Sun spotting, exhibits and talks, local astronomers adorned the Museum's west lawn with several telescopes aimed at the Sun. Tracking our local star on its path along its meridian, the telescopes looked like cannons ready to fire knowledge on the public.

Curious viewers had access to 8 different telescopes, accompanied by knowledgeable Denver Astronomical Society (DAS) Members to guide them. At times, I was the only visitor surrounded by this team of sun watchers, allowing for some stellar discussions. The telescopes had different filters allowing varied views of the Sun. Several had the red Hydrogen-alpha optical filter, which allowed only that narrow bandwidth of light to pass through the telescope. This view provided dark spots against a brilliant red Sun showing the day's featured Sunspots, but more vividly showed prominences reaching off the Sun's surface. Some of the prominences were barely visible, but as explained these tiny ruffles are extending out probably several thousand kilometers.

This deceiving size was also true of the Sunspots, which DAS members enthusiastically told people were actually much larger than the Earth in size. White Light filters showed the Sunspots in much greater detail than the Hydrogen-alpha filters. They revealed a dark black center of the spot, with a varying grey area surrounding it. Sunspots are electromagnetic fields that occur on the Sun's surface, or photosphere, creating cooler temperatures than its average 5,778 degree Kelvin heat (that's almost 10,000 degrees Fahrenheit). Through the White Light filters, the varying shade seemed to indicate the temperature differences, with the center cooler than the edges, but it was something else entirely. A DAS member explained that the center, called the umbra, is darker because the magnetic field is perpendicular to the Sun's surface. The area surrounding it, called the penumbra, is grey because the field is inclined to the surface.

We observed 5 different Sunspots, identified as 1301, 1302, 1305, 1306 and 1307. While Sunspots typically last only days or a few weeks, these numbers enable astronomers to universally reference current Sunspot activity. This becomes important as the Sun reaches its Solar maximum in the average 11 year Sun Cycle and Sunspot activity is higher. One DAS member mentioned that the Sun should soon be approaching Solar maximum in the current cycle, but its taking longer than normal in the 11 year average.

Several members had set up the small Coronado Solar Telescope, which is designed exclusively for Sun observation. The Coronado lets only 1/100,000th of visible Sunlight through the telescope, which makes it impossible to view night sky objects, even the moon. Atop of the developing Sunburn on my face, this really brought into perspective the awesome power of Sunlight. Conversations traversed the history of Sunspot observations from Galileo and even ancient Chinese astronomers to how solar storms affect the Earth. It was a thrill to hear several personal stories from DAS members who observed Solar flares. Ultimately, it was 4 hours of observing and discussion well worth the Sunburn.

Coming in from a day with the Sun, my afternoon was spent exploring our closer neighbor, the Moon in the Museum's Space odyssey exhibit. There were the high-tech lunabotics from the Colorado School of Mines and a fascinating talk on lunar geology in the anticipation surrounding the GRAIL mission from NASA set to orbit the Moon. Topping it off was meeting Bruce McCandless, who was a CAPCOM astronaut responsible for communicating with Neil Armstrong and Buzz Aldrin on their Apollo 11 Moon odyssey.

That night at Observatory Park on Denver University's campus, the DAS set up telescopes for star gazing and a grand view of Jupiter, with talks at the historic Chamberlin Observatory. Bravo to the Denver Astronomical Society for engaging the public in the delights of star gazing, whether it be those light years beyond our Solar System, or the very star that sustains us here on Earth.