gregorian/cassegrain

Hi All
I'm just wondering if anyone here would be willing to tell me, What is the deffrence between a cassegrain and a gregorian reflector?

I suspect your are talking about two different Cass scopes. A traditional Cass has a convex secondary, which is mounted inside the focal plane of the primary mirror. A Gregrian has a concave secondary, which is mounted outside the focal plane of the primary. A Gregorian secondary is somewhat easier to make, at the expense of a longer tube. A Gregorian gives an erect image.