
This amazing image of the Sun has already flown around the entire Internet. Wired journalists managed to find out from the author of the photo artist and astrophotographer Alan Friedman, as he took this picture.
Friedman takes the sky from his yard in downtown Buffalo, New York. Thus, typical candidates for celestial surveys, such as galaxies, nebulae and distant star clusters are inaccessible due to urban light. But the Sun is a completely distinguishable and accessible object in a clear cloudless sky.
On October 20, Friedman connected an alpha-hydrogen filter to his telescope, which selects a tiny piece of the visible spectrum. Hydrogen, the main component of the Sun, has strong radiation in this dark red light, allowing you to display the outer layers and flares extending from the solar disk in a sharp and detailed way.
Friedman said that several years ago this type of filter was available only for large scientific telescopes. And as before, it is not cheap - the filter cost the author $ 5000 dollars. His telescope Friedman calls the “Little Big Man” because, having a small size, he has great abilities. The telescope lens has a diameter of 3.5 inches (approximately 9 cm).
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Instead of just taking individual shots, Friedman took a 90 second video and chose only clear shots. Each exposition recorded about 900 frames, but after the selection the photographer left only the top 200.
In two separately shot 90-second videos, Friedman drew closer to the edge of the solar disk in order to remove streams of gas curving along the loops of the solar magnetic field, as well as spots and detailed bursts of the solar atmosphere.

Then he inverted the image, making all the dark spots light and vice versa. Usually, photographs that shoot the sun do not do this, says Friedman, but this gives a more authentic sensation of the sun.
Friedman's camera shoots in black and white, so he added some colors to the photos. Although in general he tries to keep his astrophotography reliable for science, he allowed a few liberties with a choice of color.
“This image is especially for the coming Halloween,” he said. "The sun can not be any other color than orange."

via
Wired