Far field wide band spectrograph lens

摘要

The spectrograph lens has an aperture in front of the first lens. A first group is provided in the order crown: convex-concave; flux gap: symmetrical or asymmetrical biconvex; flint: concave-convex. A second group, version A is in the order Crown: convex-concave; front surface may also be formed as a curved section for improved correction; flux gap: symmetrical or asymmetrical biconvex. In version B, a third group is formed as crown: convex-concave; flux gap; crown: concave-convex. This is the optimal lens for improved image quality with greater light intensity. The arrangement may have lenses in an arrangement which is a combination of versions A and B, as two individual lenses e.g. with quartz and field lenses, as the second (double) group and as the third (triple) group. The first surface of the field lens can optimally be formed as a conical section.