本帖最后由 steveyzh 于 2011-3-27 12:55 编辑
谁敢比你惨~~~~~~~~~~~~~~~~~~~~~·
liaorui4088 发表于 2011-3-27 12:27
赫赫,不是我的,别人的
有人看完后,发了这张图,大家看看什么意思....................
The ratio of the C-8 primary is F/2.
I used a rejected C-8 primary (chip on the edge of the mirror) to build a 4.6" aperture lensless Schmidt at F/3.5 for gathering data on variable stars. You can't use it visually since even reducing the aperture to 4.6 inches still leaves 2.5 waves (P-V) of spherical aberration.
Here's a simple design for a 4.5" f/3.46 lensless Schmidt configuration using your C8 8" f/2 spherical primary, using an off-the-shelf plano-convex lens from JML, part number FPX-1197200, 249.2mm EFL, 38.1mm diameter to flatten the field over F-C spectrum and 1.1" diameter. The only kicker is that the PCX lens has to be 0.1" from the CCD or film plane. If it gets any farther lateral color starts killing the performance. If you can't get the PCX lens that close, this won't work.
Just a thought. Sure echo the sentiments about your plate, but that primary should still be a beautiful sphere, ROC 32", and useful for something. |