You guys are a joy killer.

Also, you're totally lost, my initial request was for an adapter lens to essentially "enlarge" the image out of standard telescope that normally fits into a 35mm body, so the lens would only need to expand the visuals from an already created telescope image.

So this goes back to a 2000mm to 2600mm being enough for the moon with a normal lens. I don't know about lens design but I was under the impression that mirror lenses or refractive were often the norm for telescopes so all I'm looking for is essentially the "rear element" to put the image onto the film.

Heck I could probably get access to a telescope at an observatory, I just need the elements to adapt/enlarge the image onto sheet film, as I'm sure most modern observatories use smaller format digital devises.

This is a lens design thread, asking for this type of hard to come by element is just as valid as any other element IMO.