BHTU Reversed-Inclined Nosepiece

The reverse-inclined nosepiece was used only on the BHSU and BHTU scopes. This nosepiece, which is permanently affixed onto the pillar arm of the BHSU/BHTU stand, features five objective positions with standard RMS threads and a knurled black rubber  grip ring around the outer perimeter of the turret.

This assembly differs from the various modular nosepieces in that the dovetail slide has been replaced by a wedge mount (painted the same cream color as the BHSU / BHTU pillar arm), which functions to hold the nosepiece turret in the reverse-inclined orientation on the pillar arm.

Since the addition of the wedge mount between the turret and the pillar arm increases the physical tube length of the scope, an optical correction barrel was added to the physical tube (within the wedge mount) to correct the optical tube length back to the required 160mm.

The optical correction barrel achieves this tube-length reduction by using a tube lens on the lower end to convert the finite-converging light rays leaving the objective lens to rays focused at optical infinity (i.e., parallel rays), and then using a second lens at the top end of the barrel to return to finite-converging rays once again, focusing the intermediate image at the appropriate position within the optical tube.