I just got a new brain spinning book, Telescope Optics by Rutten & van Venrooij. I thought the book was out of print earlier, but notice that this is the 5th printing dated 2002! At any rate, a quick glance especially at the software section tells me that the materials are dated (eg. DOS programs ;-). Now perhaps, I might be able converse with the optics experts and more importantly understand just a wee-bit more, albeit at an elementary grade school level :-(. One thing is for certain: the book has already shown me what I thought the 0.1% I knew about optics is actually a -20% (yes negative sign) knowledge :-(. I still would love a book by Roland and/or Thomas ;-).
Anyway, the authors used the terms "semi-apochromat" or "half-apochromats" and no one seems to have a problem with this, most interesting. They used these terms to state that the secondary spectrum is reduced to 1/4000 the
focal length. Umm, most revealing. The authors then talked about Apoklaas objectives which "utilizes two special glasses, reducing its secondary spectrum
to 0.00012f)."
What is this Apoklaas? I've never heard of it or seen on the web. Is it something that was popular at one time but now no longer being made. Can someone provide more description?
Thanks,
Ron the elementary optical (but slowly rising from inept) B[ee]
Anyway, the authors used the terms "semi-apochromat" or "half-apochromats" and no one seems to have a problem with this, most interesting. They used these terms to state that the secondary spectrum is reduced to 1/4000 the
focal length. Umm, most revealing. The authors then talked about Apoklaas objectives which "utilizes two special glasses, reducing its secondary spectrum
to 0.00012f)."
What is this Apoklaas? I've never heard of it or seen on the web. Is it something that was popular at one time but now no longer being made. Can someone provide more description?
Thanks,
Ron the elementary optical (but slowly rising from inept) B[ee]
