|
The word is....offset!!!
I wouldn't blame the laser, the problem is inherent in the Newtonian design. To get a correct collimation the secondary mirror actually has to be moved away and down from the focuser. If you use a a sight tube/ cheshire to visually collimate you fix the down shift automatically.
If you want to keep using the laser as a collimator do a little research on offset in Newtonians - I know there are have been some big discussions on it in this forum in the past.
As I've said before, lasers are great for big truss tube dobs, that actually have a measurable offset, but in a small closed-tube dob get yourself a cheshire and save yourself a heap of trouble. At worst, only use the laser for the secondary adjustment and use a cheshire for the primary mirror.
|