Bio
Daniel H. Bennett was born in London in 1965 and lived in England until moving to the United States in 2000, settling in Northern Colorado.
His interest in vision and observation of the behavior of light has been life-long. On a trip to France as a young man his hosts called him “Monsieur Tête-en-l’air” (Mr. Head-in-the-air) due to his always watching for halos, rainbows, sun-dogs (parhelia), etc. He was particularly influenced by a book written in 1939 (published in English in 1954, Dover) by Professor M. Minnaert, called The Nature of Light and Colour in the Open Air. A Field Guide to Time-Varying Light Sources was conceived as a modern successor to that book, and adopts a similar approach, while revealing the secrets of modern light sources.
Daniel is married with four children, a motorcycle and two accordions.
Buy the book!
The Field Guide is available from Amazon and other outlets.
ISBN-13: 978-069-236090-3
ISBN-10: 0-692-36090-5
LCCN: 2015900348
The Blog
Here's my blog, where I'll write articles of interest, things I've learned, tutorials, suggestions for lights to go look at, musings, etc.
Arcturus - twinkling star
Two nights ago I took a photo of the star Arcturus, using my Canon 70D camera with a 200mm zoom. The exposure time was 1.0 second, during which time I hand-held the camera and moved it during the shot. Here's the result.
The trace shows a massive number of variations (over 800!) of brightness and color. This is scintillation, better known as twinkling. Our eyes aren't able to see all these variations because (a) they're too dim, so we don't see the colors, and (b) they're too fast, so we see only the largest and slowest variations in brightness as twinkles.
The cause of these variations is atmospheric - the star itself is NOT twinkling! If you took a photo like this from the International Space Station, it would be a constantly bright, slightly orange line with no variations in color or brightness.
This type of photography is really easy... go try it!
