flash spectrum ...photography by Robert B Slobins
Home Astronomy Total Solar Eclipses Image Reference: 2006-901-26



Classical Corona, Colakli - Turkey       29 March 2006

Classical Corona, Colakli - Turkey       29 March 2006



Film is still suitable for imaging total solar eclipses because of its wide dynamic range. However, its disadvantage is non-linearity in highlights and shadows.

Before digital photography became popular and affordable, I printed coronal images from film in a New York City rental lab. I could bring out most of the information on the film and flatten the dynamic range onto the paper. SilverFast now allows one to do likewise by manipulating the curves to balance the exposure and purify the color. (The corona is as white as the sun.)

After an geomagnetically active maximum, Solar Cycle 23 was winding down. The corona shows a more dipolar configuration with some separated large streamers at low solar latitudes. Observers noted a significant prominence at the upper left.

Usually the corona is the brightest at solar maximum. However, visibility on Earth depends on other factors like sky transparency.. The skies on the Mediterranean coast east of Antalya were extremely clear and the sunlight, dazzingly brilliant. Even though the leading high clouds of a weather system passed across the sun before totality, that high level moisture did very little to hinder visibility. I could follow coronal streamers visually to at least two solar diameters, even though I was on the beach. I expected such visibility at higher altitudes. I estimate from my exposures that at leat 4 times more sunlight was available at this eclipse.

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