During use of heavy photographic instruments like DSLR or cooled CCD cameras (often with filter wheels ), it's crucial to avoid flexures when we insert them into the telescope's focuser. This also important for visual use using large mirror diagonals and wide field eyepieces (which are often very heavy).
That's why we designed the OnAxisLock adapter that replaces the classic screw with a locking ring system. This allows you to perfectly lock the inserted accessory by rotating the outer ring (red): a special double ring tightens internal accessories with an uniform pressure. The OnAxisLock device also allows you to keep perfectly aligned the accessories inserted in the focuser: so you will be sure that your camera's sensor will be perfectly centered with the optical axis of the telescope.
Left: 31,8mm original eyepiece holder of ah EdgeHD 8" by Celestron
Center: OnAxisLock 50,8mm adapter for SC threaded on the rear thread instead of the original visual back
Right: OnAxisLock 50,8mm adapter for SC with 31,8mm OnAxisLock adapter
OnAxisLock 50,8mm visual back for SC telescopes is screwed directly onto the rear thread present in most of Schmidt-Cassegrain telescopes (like the SC and EdgeHD by Celestron or Meade ones) and lets you use all the 50.8mm diameter accessories. Not capatible with C6.
So it's perfect for photographic use: you can screw it on the rear thread of the SC telescope and, adding a normal T2/2" adapter, you can connect most of DSLR and CCD cameras. This assembly scheme, compared to the use of the classic SC photo adapter, lets you use 50.8 mm diameter filters, that can be screwed in front of the T2/2 " adapter inserted into the 50.8mm OnAxisLock adapter.
The particular locking mechanism also avoids spoiling the inserted accessory because the pressure is evenly distributed in the barrel. With the classic screw locking system instead the stress is instead carried on a small area and this can easily spoil the barrel.
The special design of the outer ring has been developed to allow you to lock the accessory with ease, even when wearing gloves. This way you can be sure to safely lock your CCD camera or your eyepiece even when the cold is intense.