The objective is an air spaced achromatic doublet consisting of a bi-convex crown glass lens in front of a plano-concave flint lens. The lens diameter measures 9 - 1/4 inches, with a clear aperature of 9". The focal length is 108". | |
Edge view of the objective removed from the cell. The lens and lens cell have no serial numbers or marks other than ones used for alignment. | |
Edge detail of the inside of the brass lens cell. | |
The spacing of the two lens elements is accomplished by three strips of paper spaced 120 degrees apart, one of which can be seen in this photo. |