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RaffaeleFlaminio - 22:08, Monday 27 March 2017 (431)
Measurement of the telescope convex mirror ROC
In order to measure the ROC of the convex mirror I proceeded as follows:
I placed a lamp at a distance D from the convex surface and I looked
for the image reflected by the second face of the mirror (which is flat).
The image is real and placed at a distance D' from the convex surface.
I changed D until D'=D. In this situation the focal length f is
f = D = D' = 1.305 +/- 0.01 m
I can deduce the ROC from the expression ROC = f * (n-1) where n is the
fused silica index of refraction in the visible (green) i.e n=1.4607 at
lambda = 532 nm. I found ROC=0.601 +/- 0.005 m.
In conclusion, within the error of the measurement the mirror ROC
is equal to the required value (which is 0.6 m).
I placed a lamp at a distance D from the convex surface and I looked
for the image reflected by the second face of the mirror (which is flat).
The image is real and placed at a distance D' from the convex surface.
I changed D until D'=D. In this situation the focal length f is
f = D = D' = 1.305 +/- 0.01 m
I can deduce the ROC from the expression ROC = f * (n-1) where n is the
fused silica index of refraction in the visible (green) i.e n=1.4607 at
lambda = 532 nm. I found ROC=0.601 +/- 0.005 m.
In conclusion, within the error of the measurement the mirror ROC
is equal to the required value (which is 0.6 m).