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OK, to wrap up the Search of the Holy Grail and show the final outcome....
Object:
To find a filter (or combo of filters) suitable for use with the MiniSHG to image CaK (393nm wavelength)
Solution:
The Astronomik L1 UV-IR filter blocks below 385nm and above 700nm
A Baader ND8 filter suppresses the light (12.5% transmission) across the spectrum
Plus either:
1. W47 "violet" filter - pretty common in astronomy - venus etc. This has a NIR leak suppressed by the UV-IR above. This filter has been given the thumbs up by other SHG users.
2.HOYA FL-W - this has a good transmission at 393nm and suppresses the visible spectrum. Looks promising, could be better than the W47.
3. ZB1/ZB2 - ZB2 has the best transmission at 393nm and suppresses visual but has a NIR leak. TBD
The other possible contenders are no longer available.
Kodak E39 last produced 1975
Hoya C12 Blue Cooling last produced 2015
I've ordered #1/#2/#3 filters for spectroscopic transmission testing and evaluation in the MiniSHG.
I'll hold the "best for the SHG" and re-sell the others.
(Anyone know where to find a M46 to M48 step up adaptor? ie to fit a 46mm filter on a 48mm female thread)
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