One more IYA event - today is Sun Day!

It's IYA Sun Day! Join me this afternoon from 1:30 until 3 p.m. Myrtle and Lime Streets Monrovia CA for the Old Town Sidewalk Astronomers fourth and final "100 Hours of Astronomy" observing celebration. Here is what the sun looks like today http://sohowww.nascom.nasa.gov/data/realtime-images.html I'll be out at Monrovia's Library Park with two telescopes - one is my homemade (in John Dobson's telescope makring class) safe solar telescope. And the other is a small reftactor fitted with a special h-Alpha filter. The homemade telescope shows the sun in white light - this is how the sun looks to the unaided eye. The viewer sees the photosphere, or the apparent surface of the sun, which has a temperature of 6,000 Celsius. You can say this is the sun you can "see" or what you see through a projection onto a piece of paper. The other is a telescope fitted with an h-Alpha filter, which shows just one wavelength of light -the red light of hydrogen (wavelength of 656.3 nanometers). With this we see the next highest layer of the sun - the chromosphere (temperature between 6,000 and 20,000 C.) We need a filter to see this layer because the brighter photosphere layer below washes out the fainter chromosphere, just like a bright streetlight would wash out the light of a flashlight. What you see through an h-Alpha filter are ribbony dark colored filaments against the disk and prominences on the edge, many times longer than the diameter of the Earth! I took these definitions from my writeup for the SOHO outreach website :-) http://soho.nascom.nasa.gov/outreach/past/Sidewalk/ For those who venture out to Myrtle and Lime, you'll be rewarded, not only with some great solar views, but I am bringing an AMAZING collection of educational handouts. While they last, get 3-d images of the sun in H-alpha, courtesy of the SOHO - Solar and Heliospheric Observatory, some more from STEREO ( two space-based observatories, one ahead of Earth, the other trailing behind. I also have lots of NASA lithographs of the sun. And just a very few additional 3-d cards from the SOHO/TRACE missions. And plenty of IYA bookmarks. First come, first get! See you in a half hour! Jane PS the Sun will be the subject of my May What's Up podcast! -- Jane Houston Jones Monrovia, CA 34.2048N 118.1732W, 637.0 feet http://www.whiteoaks.com Old Town Astronomers: http://www.otastro.org My JPL What's Up podcast: http://solarsystem.nasa.gov/news/whatsup.cfm Twitter: http://twitter.com/jhjones http://twitter.com/CassiniSaturn