For starters, look into the eyepiece hole (I am assuming
a reflector telescope here, with 2 mirrors) without an
eyepiece, and see if the complete reflection of the primary mirror is
reflected off the secondary mirror up thru the eyepiece
hole, AND if the secondary mirror
is centered in your eyepiece hole, which you can tell
by looking at the secondary holders (spider) mount.
They should be roughly equidistant in length.
If its not centered nearly perfectly, then you
are probably out of collimation....for starters.
Clear Skies,
Tom W.




jojo wrote:
how do I know if I need to culminating?