Here is a screen capture shot of the performance of a corrector I worked on using Corning B58-53 glass (yes, I know others have been down this road). The attached file shows the on axis performance. Screen 1 in the picture shows the final color spots to be well within the airy disk. I have other examples if anyone is interested. Coor2.jpg will show the on axis performance with the corrector knocked out of alignment. The corrector is tilted 1/2 degree and is moved off the axis by almost a 1/4 of an inch. All the color spots are still within the airy disk. Coor3.jpg will show the on axis performance at the edge of a 1/2 degree field of view. It's still almost diffraction limited at this extent. The curves on the corrector are gentle and it's a oiled triplet. The primary objective (203mm F/15) is designed as an oiled doublet using common glass. The corrector is only 85mm in diameter. I've run the design through another optics program and I get the same result. Can anyone tell me what the problem is with this approach? Is Corning B58-53 a problem? Price, availiability, etc. I can post the other files if anyone is interested.
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