July Meeting review - Bob Turner - The Hydrogen Alpha Sun

Bob Turner gave a fascinating talk on a subject unfamiliar to most of the audience- a view of the sun from a very narrow (band) point of view, a view in fact centred on 6562 Angstroms! He started with eclipse photos, the final one showing excellent prominences and continued with a discussion of sunspots, granulation, butterfly diagrams and the winding theory. He showed excellent photos of flares in H alpha light and illustrated their sizes by comparison with the earth. A rather muddled explanation of hydrogen fusion was followed by a lively illustration of the amount of information available in a spectrum, and the narrowness of the H alpha line, by getting the audience to hold a paper spectrum all round the room!

He showed a picture of his telescope and then a lot more information about, and pictures of, prominences and flares. It wasn't clear whether all the work shown was by the speaker although a lot of it was. The huge sizes and energies of flares was well brought out and the audience could not have failed to be impressed by this insight into the everyday violence of our apparently placid sun. Bob had brought a video of the Sun in soft X-ray from the SOHO satellite with him and this was shown and explained to an appreciative audience during the coffee break. All in all an interestingly different talk.

- Stan Waterman

[Ed: For more information on h-alpha observing: check out the article: observing the sun in h-alpha, on the website of the prairie astronomy club: http://www.4w.com/pac ]