|
Good optics have an accurate figure (the right curvature)
Good optics have a uniformly smooth figure without lumps and bumps
Good optics have a well polished surface.
Cheap optics will not have all of the above, even if they do satisfy the term "diffraction limited".
Is the difference visible? Heck yes! It was immediately apparent to me the first time I pointed my new dob with Suchting primary toward Jupiter.
Even in poor seeing the view was much cleaner without anywhere near the amount of scattered light lighting up the background as i see with my gso diffraction-limited dob.
|