Attempted CaK homebrew

[smerral]

Attempted, because it doesn't appear to have worked. My intention was to remove the diagonal from the Lunt B600 Cak module and substitute the 394DF15 filter for the blocking filter, thereby ending up with a straight through module. I was under the impression that this works for the CaK PST. But the image is far too bright for the webcam which suggests the new filter is not acting as a blocker, and where I can see detail on the limb the CaK details appear to be missing. Am I missing something? Or is there some way the Lunt BF is different from the PST one?

[marktownley]

I was shooting Cak today at 1/2500sec - it is pretty bright - does the webcam go that 'quick'?

[smerral]

Ummm, I'm not sure Mark. I think I'll have to wait until my DMK arrives before I can really judge it.

[smerral]

Well apparently the spc900 does 1/10,000 sec - so that's not the problem. I've noticed that the filter coating does not go all the way to the edge. Could stray light be the problem?

[smerral]

Hi Joe,

I think those diagrams explain it. The crucial filter I have tried to replace is the one at the eyepiece end of the diagonal; I can see now that this is actually two filters, one of which is the crucial narrowband one. So it's not going to work.

Brian