Quote:
Originally Posted by Ian Robinson
Is it necessary to use a centre spot on the primary when laser collimating ?
|
Yes it is.
Quote:
Else the laser will not retrace it's own path ??!!?? 
Thoughts anyone ....
|
The laser could strike anywhere on the mirrors surface and the mirror could be tilted to make it retrace its own path. Only one orientation is correct and that is when the laser strikes the exact centre.