Hmmm... I might have answered my own questions:
Quote:
Q: What are the thread sizes on Lumicon filters?
A: The 1.25" filters employ industry-standard 1.125" x 42 tpi threads (except for Questar/Brandon, which use a thread pattern unique to Questar). The 48 mm filters employ industry-standard 48 x 0.75 mm threading, which thread into 2" eyepieces. All larger filters use the given size with 0.75 mm pitch (e.g. a 72 mm Minus Violet filter has 72 x 0.75 mm threads).
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I found that on the Lumicon FAQ page:
http://www.lumicon.com/faq.php
The only problem is the thread in the back of my 1.25"to 2" adapter is definitely not .75mm pitch... it's 0.6mm pitch
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Any one have some thread gauges that can verify? (Or doesn't this thread fit a 2" filter???
)
Al.