The Baader Planetarium Off Axis Guider (BFM-OAG) is designed for direct connection to the Baader FlipMirror II Star Diagonal. This is the only OAG prism that can be tuned to actively center a star on the guiding chip.
Use the BFM-OAG to attach an autoguider camera to a Baader FlipMirror II Mirror Diagonal that works with both positions of the mirror.
The distance between the optical axis and the center of the OAG prism is 17.5mm (once the 4mm spacer ring is removed). This distance provides the largest possible vignetting-free field while retaining all the advantages of the large and movable prism. With one or two 1.25" nosepiece extensions (1905130) you can place virtually any camera on the Off Axis Guider so that it is parfocal with the imaging camera.