|
Excellent article Don.
I agree with Matt. Every Newt owner should have a read and while is does look complicated, diagrams do makes it easier to understand.
I will add that a laser can be used to check the movement of the focuser. With the focuser all the way in, observe the laser dot on the centre mark on the primary. As you wind the focuser out, see if the laser dot moves across the centre mark.
After using a cheshire sight tube, I will use a laser to check the primary alignment by observing the return beam to the exit hole. I place a small pocket mirror behind the secondary mirror.
What I look for is a red "donut" around the exit hole and the return beam centreing over the exit beam. (I do this by touching one of the spider vanes)
I will then wind the focuser in and out fully to check any movement.
If both the Cheshire sight tube and the laser agree, it's a fair bet that the mirrors are pretty well collimated.
|