The Sun

You can fit one million Earth’s into the sun. From WIRED:

This stunning portrait of the sun spread like hot plasma all over the internet yesterday. Wired.com spoke with artist and astrophotographer Alan Friedman to find out how he made it.

Friedman shoots the sky from his backyard in downtown Buffalo, New York. That means the usual celestial candidates — galaxies, nebulae, distant star clusters — are washed out by the glow of the city. But the sun is fair game, as long as the sky is clear and turbulence-free.

“I don’t care about sky glow at all,” Friedman said. “I just need atmospheric steadiness.”

On Oct. 20, Friedman hooked his telescope to a hydrogen-alpha filter, which selects a tiny slice of the visible light spectrum. Hydrogen, the chief component of the sun, radiates strongly in this deep-red light, letting both the sun’s outer layers and the feathery filaments that extend away from the disk show up in sharp detail (see photos below).

Until a few years ago, Friedman says, this kind of filter was only available for research-grade telescopes. They’re still not cheap — he got his for around $5,000. Friedman’s telescope, which he calls Little Big Man, is small but mighty. The light-collecting aperture is about 3.5 inches wide.

Instead of just snapping a photo, Friedman took 90 seconds of streaming video and selected only the sharpest frames. Each exposure captures about 900 frames, but Friedman threw all but 200 of them away.

Read More http://www.wired.com/wiredscience/2010/10/making-a-sun-photo/