The new Japanese-made Vixen VSD100 f3.8 telescope features an innovative 5 element lens design with an SD lens in the front objective group and an ED lens in the rear group for a large, flat, evenly illuminated field with superb colour correction. The blue halos around stars that are perceptible in simpler designs are completely absent. In addition, astigmatism and coma aberrations are corrected to a very high level.
See this remarkable APOD image from Paul C. Swift made using a Vixen VSD100 f3.8, Starlight Express SXVR-H18 and Baader filters.
The lenses of the VSD100F3.8 have modern lens multi-coatings developed to match the characteristics of each lens element to achieve 99.9% light transmission at the maximum per lens surface and high contrast without ghosting or flare (patent pending).
The Strehl intensity of the VSD100F3.8 optics is approximately 10% better than most 4 element lens designs.
The image circle is as large as 70mm in diameter (60% illuminated) and the star images are as small as 15 microns around the corners, resulting in excellent field flatness.
The Vixen VSD 100 f3.8 also features a large helical focuser with fine focus scale for smooth, precise, repeatable focusing.
A 3-element focal reducer (0.79x) and a 4-element tele-extender (1.58x) will also be available. When used with these accessories, the VSD100F3.8 can be transformed to an even faster 300mm f3 astrograph or a versatile 600mm F6.0 telescope for both imaging and visual astronomy.