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Secondary question for an expert
Hi Guys, I have a question about my telescope and its secondary. I plugged all my values into NEWT and got a 100% illuminated circle of 0mm. Now I have been using my telescope for a few weeks now set up like this and vignetting is not that bad. I assume the light that I am seeing is from the 75% light rays even at the center of the field.
I changed the diagonal axis value in newt up and down and saw what effect it had on the 100% illuminated circle. Above 80mm saw the 100% circle move up. So I went investigating and bintel sell 88mm secondarys. Plugging in this value gave me a 17mm 100% illuminated circle. My chip is 17X13mm approximately so I have ordered one of them.
Now I understand that I am going to lose some light from the secondary size increasing ( the area went from 12% to 17%) but am I right in thinking that my chip should see an approximate 20% gain in light from the 100% rays as apposed to the 75% that I think it gets currently.
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