Mirror lock
All ACF f/8 models feature a primary mirror locking mechanism, which effectively prevents movement of the primary mirror during long exposure astrophotography or observing. Turn the lock knob located just above the telescope’s main focus knob and the progressive-tension primary lock completely cancels any residual image shift due to mirror movement during visual, photographic, or imaging applications.
Carries full one year UK warranty by Opticstar Ltd on behalf of Meade Instruments Corp.

Meade ACF f/8 optics.