Vixen Telescope SDP65SS Optical Tube Assembly

Specially designed for astrophotography

The SDP65SS refractor is designed for astrophotography. The lens is made of four elements including SD glass, high refractive index ED glass, and lanthanum glass with optimum arrangement of power of lenses significantly reducing axial chromatic aberration, while successfully suppressing astigmatism to the same level as the VSD-series flagship models.

Excellent image flatness

IC1805 (The Heart Nebula) and IC1848 (The Soul Nebula)
Optical system: SDP65SS
Camera: ZWO ASI6200MM Pro (35mm full-frame)
Filter: LRGB filter
Exposure time: 100 min. {L: 5 min. x 8 (Gain 0), R/G/B: 5 min. x 4 (Gain 100)}

The optimized power arrangement of the four-element lens including SD and ED glass provides an extremely flat image plane without the need for a flattener lens. It provides a high level of correction for distortion of peripheral star images, forming beautiful star images across the entire field of view of the φ44mm image circle.

Aboundant peripheral illumination

It is optically designed to narrow light flux at the final lens to minimize vignetting. Since there is almost no vignetting due to the optical system, it is very unlikly to appear vignetting due to the camera mount, etc. and as a result very rich peripheral light is available with any imaging systems. More than 90% of the light is secured at the very periphery of 35mm full-frame image, which is expected to eliminate the need for peripheral light reduction correction by image processing or facilitate the image processing.

New focuser design

It employes a mew focusing system that moves the objective lens back and forth using a rack and pinion (moving objective type). Because the eyepiece section does not move, focus adjustment can be made smoothly without being affected by the weight of installed accessories such as a camera. In addition, when using an electric focuser, there is no hassle of having to retract the tube before turning off the power as with an extendable drawtube.

Readout for scales (with vernier)

Incorporates a readout for scales serving as a guide for the focusing position, making it possible to read in 0.1mm increments with the vernier.

Compatible with focuser

For more precision focusing, it is compatible with a Dual Speed Focuser (optional) or ZWO EAF (electric focuser).

Lightweight and compact desgin

It is extremely compact in 413mm long, and even more compact at 359mm when the retractable dewshield is stored, making it easy to carry around.

Supports imaging in a wider field of view! SDP Reducer 0.8x (optional)

The optional reducer 0.8x will reduces the focal length of the SDP65SS by 0.8x, alternating the F-ratio from 5.5 to 4.4. φ30mm image circle (Over 90% light intensity at the very periphery, covering APS-C). Approx. 60% light intensity is ensured while minimizing star image distortion, even at the very periphery of the φ44mm full-frame format,

M45 (The Pleiades)
Optical system: SDP65SS + SDP reducer 0.8x
Camera: ZWO ASI6200MM Pro (35mm full-frame)
Filter: LRGB filter
Exposure time: 100 min. {L: 5 min. x 8 (Gain 0), R/G/B: 5 min. x 4 (Gain 100)}

Star image comparison using spot diagrams (SDP reducer 0.8x)

The FL55SS with Reducer HD for FL55SS Kit has been highly praised for its excellent imaging performance. But the peripheral image is somewhat distorted when the captured image is enlarged to 100 μm scale in the spot diagram. On the other hand, with the SDP65SS, the star image is well-balanced and rounded.

Photography System Chart

The FL55SS with Reducer HD for FL55SS Kit has been highly praised for its excellent imaging performance. But the peripheral image is somewhat distorted when the captured image is enlarged to 100 μm scale in the spot diagram. On the other hand, with the SDP65SS, the star image is well-balanced and rounded.