Category talk:Cassegrain telescopes
Not every Cassegrain is a Schmidt-Cassegrain!
On 10 May 2010 user [[User:Foroa}Foroa]] has changed this category Category:Cassegrain telescopes to become a category redirect to Category:Schmidt-Cassegrain telescopes. I undid this modification, as it is basically incorrect.
A classical Cassegrain telescope has an "open" top end. Schmidt added a 4th order correction plate at the top end of the tube, making it a "Schmidt-Cassegrain telescope" (or "Schmidt telescope" for short). In a similar way, Maksutov added a meniscus-shaped corrector lens to the open top end of the classical Cassegrain desing, making it a "Maksutov-Cassegrain telescope" (or "Maksutov telescope" for short). These are to three different designs.
If there are only a few images of one of say, Maksutov-Cassegrain telesopes, these may of course be categorised as "Cassegrain telescopes", of which they are a derivative. The same is true for Schmidty-Cassegrains.
But it is definitely wrong to categorise "Cassegrain" as "Schmidt-Cassegrain". It would be the same as categorising "Cars" as "Opel", instead of categorising "Opel" as "Cars"!