Quote:
Originally Posted by Lognic04
I'm sure it's a lovely scope, but I have to say that test report is pretty strange. "Mirror roc" is 630mm - firstly it's not a mirror  And secondly, the ROC is twice the focal length in any case. This must be misprinted? The P-V surface error is supposedly 1/8 wave but the strehl is 0.993? VERY optimistic prediction. And the actual surface doesn't lie either, with there being a pretty big turned down edge. I'd be interested to see an actual star test though! Congrats on your purchase! |
Well spotted Logan with the mirror. However, I would argue that for a lens made of glass with refractive index of 1.5, the RoC = exactly focal length - it is not a mirror after all. Also, if we use the stated rms to calculate Strehl with well known formula, we will arrive at about 0.993. PV error of 1/8.8 is pretty good for a lens I would say. Not sure where do you see big turned down edge either
