foucault test for refractors

[andrew63]

came across this very revealing set of images for different refractors, just click on image to enlarge.

I think it shows why some telescope views are a lot purer - takahashi white - than others. It also confirms the comparative large amount of red aberration on the popular synta 100ED types.

http://rohr.aiax.de/foucault-bilder.jpg

andrew

[jordan20]

hmm very interesting !. thanks for posting

[Peter Drew]

Pretty zoney as well as colourfull, some of them! .