Quote:
Originally Posted by bojan
Not necessarily...
Then put the the secondary back in place (make sure it is offset away from focuser to avoid vignetting) and adjust the laser beam to point to the centre of the mirror.. then adjust the returning laser beam such it is hitting the secondary at the same spot by tilting primary.
|
Above is a quote from the first reply to the OP which happened to be yours. You asked the OP to offset the secondary mirror away from the focuser to avoid vignetting which later you explained to be light cone vignetting. You did not question the OP to find out if such an offset is needed. I can tell
from the OP's photo that the secondary mirror is mounted centrally on its stalk without an offset. Asking the OP to move the secondary mirror away from the focuser unnecessarily will cause opposite spider vanes to be at an angle with respect to each other which will worsen the diffraction spikes. In addition, suggesting that the away-from-focuser secondary mirror offset is needed to avoid light cone vignetting is incorrect.
Jaosn