Dome Geometry?

I appreciate you taking time to reply. I asked not so much because I'm
worried but because I don't know why the offset is necessary for a
wedge/fork mount combination but not for a GEM.

Davoud,

I have experience using a fork mounted C-14 on a central pier in a dome.
Years ago there were two different Newts on GEMs in the dome. While the dome
is big enough to accommodate the 'problem' the C-14 is still in a difficult
position when pointing at the southern sky. The eyepiece is close enough to
the North side that the observer must be on the side of the scope rather
then behind it. This is a problem because the observatory design requires
using a rolling ladder to reach the eyepiece and the entrance is thru a
hatch in the north side of the floor. The scope would be easier to use if
the pier were about 12 inches south of center, or if the C-14 were on a GEM.

George Normandin