This optical cell is used to allow a Binotron-27 with Power Switch to be used on Lunt H-a scopes.
This optic is threaded into the telescpe side of the blocking filter diagonal after the hollow tube of the lunto diaognal on the telescpe-side is removed. This optic has female 42mm T threads and the Lunt BF Diagonal has 42mm male threads. Included is a 1.25" nose for the Binotron which threads into the Binotron Power Switch AFTER the Binotron's 2" Nosepiece is removed.
Resulting Power Switch magnifiction factors are 1.3x/2.3x and 3x. The higher power of 3x is difficult to use and out travel of the focuser of the Lunt will likely not allow focus. However, an extension piece that is threaded onto the Optical Adapter will allow the entire diagonal to be slided outward and the highest 3x will reach focus. Note that the 1.3x/2.3x magnfications are most recommended because of the thermal currents that occur coming up from the ground due the Sun's heat, especially near noon time.