[Sharlin]

[T]hese surveys use small telephoto lenses rather than small reflectors.

Well, small telephoto lenses relative to most telescopes, pretty darn big relative to most camera lenses ;)

[wiredfool]

Cheap telescope. Very expensive camera lens.

[dekhn]

I bought a $1000 refractor telescope, then got a prime focus adapter for my camera. It's basically a big 1200mm zoom lens.