Quote:
|
Using this calculator the required diagonal offset is approx 5.56mm which is within the error margin of the measured value. The mirror is undersized, and doesn't even provide 100% illumination at the center of the image. Whilst this is not a big problem, I have replaced my secondary with a larger one (4 inch).
|
A 4" secondary, that's scary!
The original 3.1" secondary provides an acceptable field for visual use. A popular fast system with the imaging crowd, its characteristics might be a little less happy for the visual observer.
Here's another thread on the GSO 12" F4 Newt
http://www.iceinspace.com.au/forum/s...71&postcount=1