Hi,
Bruce.
to the 'mad house'. MERRY CHRISTMAS.
Sounds like you are O.K. with the laser side of collimation. This is probably more accurate than 'mechanical centre', which is what you get with the film can cap.(correct here please guys?).
All dobs require a bit of 'offset' towards the primary & away from the 2ndary. 4~5 mm sounds right. (if you look down the front of the t'scope, it doesn't look right, but it is). You are lining up the optical centres.
Q. If you look thru the focuser without anything in it, (move your eye around & back, to line everything up), is the 2ndary in the centre at the bottom?
I've found it's easier to start with a sheet of white paper, bluetacked to the inside of the tube, opposite the focuser, to line up the 2ndary FIRST.
Should see an white circle outside/around the 2ndary. Adjust it till it's in the centre. Adjust primary, then do a laser check.......
Do a 'STAR TEST' after the laser collimation to check & make final small adjustments.
HTH.
L.
see here >
http://skyandtelescope.com/printable...rticle_790.asp
& here >
http://www.andysshotglass.com/Collimating.html
ps. You shouldn't need/use sticky tape or any kind of 'gap filler' when collimating.
You don't with all your E/Pc's, do you?
