Newtons original reflecting telescope had a primary mirror of 33mm in diameter. If a human eye has a diameter?
raul asked:
of 8mm, how many photons per second could newton detect with the telescope compared to without? Assume 100% reflectivity of the mirror and that he just used one eye. I squared 33 and 8 and subtracted them from each other. The choices are 8, 17, 33, 38, 1089. I believe it is 1089. Any confirmation?
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of 8mm, how many photons per second could newton detect with the telescope compared to without? Assume 100% reflectivity of the mirror and that he just used one eye. I squared 33 and 8 and subtracted them from each other. The choices are 8, 17, 33, 38, 1089. I believe it is 1089. Any confirmation?
March 3rd, 2010 at 7:55 am
The amount of light collected by a sensor is proportional to the surface area, and the surface area is proportional to the square of the diameter. The telescope’s 33 mm aperture is 33/8 = 4.125 times longer on a side, which makes its surface area 4.125^2 = 17.015625 times larger. So the telescope allowed our hypothetical Newton to stuff about 17 times as many photons into his eye. David
March 4th, 2010 at 4:12 pm
The area of the human iris, 8 mm, is pi X 16 mm, or about 50.3; the area of Newton’s reflector is 16.5 squared X pi, or 855 square millimeters. So the answer is 17. It’s the same as the ratio of the diameters squared. David A
March 6th, 2010 at 11:52 pm
The 33 mm mirrors could see (33/8)^2 times the photons that the humans eye can. This ratio is 17. Roger