How do my EdgeHD mirror support knob flexible tension clutches work? Will they interfere with focusing my scope?

The EdgeHD mirror clutches apply tension to a flexible rod attached to the primary mirror support. With enough tension from both clutches, they are effective greatly lessening mirror shift or mirror flop when the scope is moved around in different orientations while in use.

Because they are flexible, the mirror clutches won’t prevent focusing while tightened. However, because they do put force on the mirror, they should be loosened when focusing. Otherwise the combination of their force and the focusing effort may put unequal pressure on the primary mirror, causing it to bind or unevenly shift while focusing. 

The EdgeHD 14”, like older Celestron 14” tubes, has two regular mirror locks in addition to the clutches. These locks do just that – lock the mirror. They should be used when the telescope is transported, not to prevent mirror shift. Never focus when these locks are engaged - you may damage either the focuser or mirror.