[Tom Summers (Tom)]

Can some one help out with this: I have a project on at the moment to build an 8" Newtonian and am having a bit of trouble with the secondary mirror placement. I have a formula which requires a value (h) which is defined as, The distance of the desired location of the focal plane from the optical axis, My question is, is this distance measured with the focuser fully extented with an eypiece in it or in the home position and no eyepiece. I have a grip of all the other bits but this one puzzles me, thanks in advance.
Tom