The projection and focal adapter consists of two parts - the projection part and the focal adapter. The projection part is used with an eyepiece for achieving a long focal length with small objects, e.g. for individual craters. Use the focal adapter without the use of an eyepiece so employing the focal length of your telescope - for taking photos of the entire Moon, gas nebula or galaxy.
projection adapter for 1.25-inch eyepieces of up to 38mm outside diameter
can be used as a focal adapter with a T2 thread
continuous zoom - magnify the image by sliding the adapter further out