100 Hours of Astronomy

100 HOURS OF ASTRONOMY 

This week, astronomers are celebrating the 400th anniversary of Galileo's original telescopic exploration of the sky with "100 Hours of Astronomy," a cornerstone project of the International Year of Astronomy. Running from April 2 through April 5, many different public programs are planned worldwide. Is one of them near you? Visit the 100 Hours web site to find out: http://www.100hoursofastronomy.org/ Note that the celebration ends on Sun Day, April 5th, a special date devoted to observations of the sun: http://solarastronomy2009.org/100-hours-sunday/ .

Galileo Galilei (15 February 1564 – 8 January 1642) was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations, and support for Copernicanism. Galileo has been called the "father of modern observational astronomy", the "father of modern physics"





ISS MOON TRANSIT: The International Space Station has grown so big and bright, you can see it even when it is directly in front of the Moon. Oscar Martin Mesonero of Salamanca, Spain, took this picture on April 1st:

"I recorded the transit using my 8-inch Celestron telescope and a Canon EOS 50D," says Mesonero. "The ISS was much brighter than the lunar background."

His snapshot caught the space station passing over the Sea of Nectar (Mare Nectaris). Just to the north of the transit path is the Sea of Serenity where Apollo 11 astronauts landed 40 years ago. The ISS seems so close to lunar soil that the crew could hop out for a visit of their own. In fact, the Moon is about 384,000 km away from the Earth-orbiting spacecraft. Astronauts won't be truly close to Nectar until 2020. The ISS will join the Moon in the evening sky again this weekend. Check the Simple Satellite Tracker for viewing times.

POLLEN CORONAS: "The 2009 season for pollen coronas has begun," says Peter Paul Hattinga Verschure of the Netherlands. He photographed the onset from his garden in Deventer:

"On April 1st, clouds of pollen were blown out of the pine tree by a dry northeasterly wind," he says. "When the pollen passed in front of the sun, an intensely colorful corona formed."

Coronas appear when sunlight is scattered by very small particles in the air. The most common coronas are produced by water droplets in clouds. Pollen grains work just as well--and in some ways they are even better.

"Unlike water droplets, pollens are non-spherical--and this adds to their magic," explains atmospheric optics expert Les Cowley. "Many have air sacs to help carry them in the wind. These align the grains to give beautiful elliptical coronas with bright spots."

Is there pollen in the air where you live? Be alert for coronas!