HowTo: Secret of the Hartmann Mask... Revealed!

[Geoff45 (Geoff)]

Since using the mask with triangular cutouts, I notice great diffraction spikes at focus--makes it easy to know when you're there.
Geoff

[Davekyn (David)]

Would it make any difference if the triangles cross over the spider vanes...because I can't work out how to make up another fancy drawing to get 4 or 2 shapes dead centre?

[[1ponders] (Paul)]

Probably not. Your spikes might be a bit longer or you may have more spikes.

[Davekyn (David)]

Thanks...I'll give it a go

[originaltrilogy (Petr)]

Is also good for collimating SCT!
http://preview.tinyurl.com/a5kcym7