23 Dec
2006
23 Dec
'06
3:30 p.m.
Yep, a check of the Protostar Website shows that the curved option is only for "tubes" up to 15". IIRC, the reason was unacceptable vibration when you go larger due to more massive secondaries.
Drat. Maybe you could make them out of that transparent aluminum from Star Trek 4, the whale episode. I think the whales were humpbacks, but one of them could have been Shatner.