 My "firstlight" photograph of Vega in the summer of 1986 with my unique Simplified Schmidt camera. This camera uses a field flattener to make the image a flat plane instead of a shallow spherical surface. Since the image is now flat, I do not have to use cut film and deform it into a curved surface. In fact, I made a small cube to hold two 35mm film canisters - one to hold unexposed film and the other to wind-up the exposed film as it is taken. The film winds off the full spool between a plate of glass and the flat bottom of the field flattener, and onto the empty spool. This is done with a small DC motor, and an IR LED and phototransistor which count the sprocket holes and wind the film the proper amount. This is a 2-minute exposure on unhypered Kodak 2415 film. The primary mirror is 10 inches in diameter and F/1.64. The clear aperture is 4.5 inches, and the film cube is 2.25 inches. The Schmidt camera is F/3.6 neglecting the central obscuration, and F/4.5 including it. The square obstruction and support struts are visible in Vega's diffraction patern as 4 spikes; but the field is free of strong reflections and ghosts.
In ASTRONOMICAL TELESCOPES chapter 'Aberrations of a Schmidt Camera', I. S. Bowen discusses field flatteners and states: "Such a field-flattener lens should be plano-convex, the convex surface having a radius of approximately (N-1)f/N, in which N is the index [of refraction] of the glass and f is the radius of curvature of the field to be flattened. To reduce aberrations to a minimum, the plane surface of the lens should be placed as close as possible to the photographic emulsion."
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  This is a 24-1/2 min. exposure of the North Star (Polaris) taken on 9/9/2001 from 8:37-9:43pm MDT. I used the KAF-0400 CCD and a fast wide-angle Pentax camera lens (50mm f.l. at F/1.4). It is a composite of 49 30 sec. exposures. This series of photos started just as the sky became dark enough to see satellites, and not fog a 30 sec. time exposure. It is also a reversed (black stars on a white background) paper print on which I drew lines (to show earth satellite trails) and red dots (to show satellite flashes). The 4 trails and 18 flashes had to be marked by hand on this "worksheet" because after combining 49 frames, the final composite photo did not show these relatively transient events. Polaris is the large dark spot just to the right of center, and the large blob at the upper-left corner is the edge of a tree limb. The cross-hatched pattern is an artifact from scanning the worksheet to make this .jpg.
Except in 3 instances, every red dot (flash) is from a different satellite (because the frames are widely spaced and satellites move very far in this amount of time). For example, the 2 flashes to the right of Polaris are from frames 11 and 48. The 10 flashes above and to the left of Polaris are from frames 9, 40, 5, 15, 28, and 37. However there are 2 double-flashes, and 1 triple-flash from the same satellite. (These flashes are not cosmic ray hits, because they are quite strong and uncharacteristic of all other cosmic ray hits I've seen in the 11 years I've used this chip.) With that said . . . here's the $64,000 question: do you think these flashes are light reflected from the sun or Polaris? Consider that the sun is 30 (or so) magnitudes brighter than Polaris; BUT there is a tight grouping near Polaris, and forward scattering at a few degrees is usually much greater than at the sun's angle - some 90 degrees away. Send-in your answer!
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