This Vixen Optics Extender PH Kit for R200SS is a high-quality, made-in-Japan focal extender lens for serious astrophotography. The Vixen Extender PH works with the optical surface of a parabolic mirror to correct coma aberrations on Newtonian telescopes. It can transform the Vixen R200SS reflector into a research-grade f/5.6 astrograph with no false color. This extender provides a wide illuminated field of view with no dim images at the edges of the field of view, and the coma correction is perfect throughout the image circle.
Extends Focal Length by 40%
The Extender PH not only extends the focal length of the R200SS from 800 to 1120mm (1.4 times) but also corrects coma aberrations inherent in Newtonian reflectors.
44mm Image Circle Covers a Full-Frame Imaging Sensor
The image circle of the Extender PH covers a full-frame DSLR with a 35mm image sensor format (36 x 24mm). It achieves sharp star images throughout the photographic field of view.
Coatings for Optimal Light Transmission
The same anti-reflection AS coatings that are renowned for surprisingly high light transmission (99.9% per surface) on Vixen's high-end VSD100F3.8 OTA are provided on each of the lens surfaces of the Extender PH. The matte finish eliminates internal reflections and loss of light.
Use for Visual Observation
The Extender PH can be fit on any R200SS reflectors sold in the past. It is available for visual observation with an addition of an optional eyepiece adapter.
Use as Barlow Lens
The Extender PH works as a Barlow Lens by attaching to a 2" visual back to the R200SS. You will obtain sharp images without coma in both visual observing and astrophotography.