likeafieldmouse:
Alan Friedman
An amateur astronomer’s photographs of the sun from his backyard observatory in Buffalo, NY:
“Using a small telescope and narrow band filters I can capture details in high-resolution and record movements in the solar atmosphere that change over hours and sometimes minutes. The raw material for my work is black and white and often blurry. As I prepare the pictures, color is applied and tonality is adjusted to better render the features.
To record my images, I use a filter that passes only a narrow slice of the deep red end of the visible spectrum. Called a Hydrogen Alpha filter, it is attached to the front end of a small (3.75″ aperture) telescope. Think of it as a 450mm f5 telephoto lens. The camera used is an industrial webcam. It can stream images at a speed of 15 to 120 frames a second.
Our atmosphere is a formidable obstacle to capturing sharp photos of a distant object. Streaming many frames in a short period of time allows me to temper the blurring effects of air turbulence. Each photo is made from many thousands of frames. Most frames are unusable, distorted by the heat currents rising from rooftops and asphalt driveways. But a few will be sharp. I review the video frame by frame for these moments of ‘good seeing’. The high quality frames are selected and then averaged to form the raw material for my photographs.”
