Great Article, Don!
I wonder... Are the GOTO S-APO triplets and/or Fluorite Doublets subject to the same Flint Hazing seen with Takahashi versions? Ditto for the Canon, Pentax, & Mizar objectives. I see so few of these, that I can't make a determination.
Thanks I enjoyed the research and connecting with our Japanese friends.
Great question.......I know of one Super-APO fluorite that came up for auction in the last few years. It did not have hazing. I think there was a reason Goto did not pursue more Fluorite production. The reason is conjecture, but I believe Goto wanted the APO's they designed to be manufactured not only for the amateur market but for professional use as well. IE: 20-25CM.
As for the non-Fluorite I know of one Super-APO triplet sold recently with no hazing. The 1977 triplet-type standard-APO I own is almost pristine besides some dust.
We believe the Suda observatory telescope is a 20cm Super-APO triplet. We hope to answer that definitively in the near future.
Edited by PawPaw, 02 July 2023 - 09:44 AM.