The projection adapter is a tool mostly used for planetary photography. By placing a 1.25" eyepiece inside, you can achieve significant focus stretching, just like with a Barlow lens - but with more flexibility, as different focus eyepieces give different stretching.
In the inlet of the device, an eyepiece with an outer diameter of up to 38 mm can be inserted. On both ends of the adapter there is a T2 thread for mounting: on one side you can mount your SLR camera with the appropriate T2 ring, while on the telescope side you also need a T2 thread for mounting (T2/1.25" adapter not included!)
For the variable model, you can increase the amount of stretch by moving the camera 38 mm away from the eyepiece. As a T2 extension, the min-max length is 88-126 mm.
