The fast f7 focal ratio captures elusive and faint deep-sky objects easily with incredible detail. This lens has outperformed mirror type astrographs twice its size, as we had predicted. The EDF is superb as a visual instrument as well. It is easily capable of high-power observations of the moon and planets.
Secondary spectrum is nearly absent at any power.
Deep-sky views are equally impressive due to the very high transmission of the three glass types. The heart of the front triplet apochromatic lens is an ED glass and 2 crowns. This combination totally eliminates all secondary spectrum, coma and spherical aberration. The rear lens is a 2ement field flattener that eliminates astigmatism and field curvature. In the visual configuration, the rear 2-element lens is removed and replaced with a standard visual adapter.