That was a bit of a rant...well
Prime Focus is generally used in the amateur literature to denote the placement of the camera body at the focuser of a Newtonian. There are no lenses between the mirrors (primary and secondary) before the film plane in this arrangement. Professionals generally have bigger scopes than amateurs so they can mount the camera (in the days of film) inside the scope where the secondary mirror would normally go. Amateurs are generally reduced to attaching the SLR to the focuser. To me both are Prime (ie first) Focus. As I recall Steve Lee had a similar rant, and I think you are both wrong. DSLR's are generally used in the same position but with thier camera lens, in what used to be called the afocal method. Essentially, words mean what they are popularily accepted to mean.
My understanding of a Plossl eyepiece is one with 2 sets of lens elements, generally of 2 each. I understand that TeleVue actually has a patent on thier version of the Plossl design. I can't see why other designers can't introduce 5 or 6 lens elements in 2 groups, as a modified Plossl. This would give some design freedom, and the basic characteristics of the Plossl (ie 50 degree AFOV) is preserved. It is a marketing challenge to sell a new design of eyepeice is it is only a modification of an existing design and you call it something else. People will say that is it only a Plossl. To the end user, if they buy a Plossl eyepeice, they don't take it apart to check the number of lens elements or groups of elements, most of us only care that it works are advertised. So get a grip.
The popular usage as defining authority is most illustrated in the term "dobsonian telescope" for just about every alt-az mounted newtonian reflector, even though the original dobsonians were plate glass mirrors with sonotube OTA's and big wooden mountings. If you used pyrex mirrors in a metal tube with a truss is it still a dobsonian? Popular usage would suggest yes.
Why? Do you usually call your telescope by its mounting type or optical design? Do I call my fork mounted SCT a "fork"? My GEM a "GEM"?
However the multitudes have spoken, so I am forced to call my dobsonians "dobsonians", not alt-az newtonians.
end rant
The correct (über pedantic version) term is finder telescope. Indeed not all finder telescopes are refractors, I can think of at least one telescope that uses a 20" reflecting telescope as it's Finder Telescope.
