The best focal extender designed for Newtonian telescopes for serious astrophotography.
Made in Japan and designed for astrophotography, this premium extender lens system converts the R200SS parabolic mirror Newton reflector into an F5.6 astrograph. The Extender PH kit was developed to increase the focal length by a factor of 1.4x It increases the focal length of the 800mm (F4) R200SS Newton reflector to 1120 mm (F5.6).
The optical system structure of 4 elements in 3 groups corrects the coma error to render sharp images up to the edge of the field of view. The extender illuminates the field of a full-frame camera (44 image circle). When used in combination with the eyepiece adapter, the 31.7 mm eyepiece can be used for visual observations.
The same anti-reflective AS coatings used on our high-end VSD 100 f/3.8 astrograph are also used here to provide an outstanding light transmission of 99.9% per lens surface.
The completely matte surface in the interior keeps loss of light, ghosting and scattered light to a minimum. When used with the 50.8 mm eyepiece adapter, the extender PH kit provides a high-performance Barlow lens for visual observations and eliminates coma and aberrations over the entire field of view.
