Vixen Optics SD81S 81mm f/8 ED APO Refractor Telescope (OTA Only)

Vixen Optics SD81S 81mm f/8 ED APO Refractor Telescope (OTA Only)

Vixen Optics SD81S 81mm f/8 ED APO Refractor Telescope (OTA Only)

B&H # VISD18S MFR # 26146

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Product Highlights

  • 81mm Refractor-Style OTA
  • 625mm Focal Length, f/8 Focal Ratio
  • FPL53 Extra-Low Dispersion Glass
  • Apochromatic Lens Configuration
  • Anti-Reflection Multi-Coated Optics
  • 60mm and 42mm Adapter Threads
  • 1.25" Dual-Holder Flip-Mirror Diagonal
  • Mounting Rings with Vixen Dovetail
  • Red-Dot Finder
  • OTA Only, Mount Head and Tripod Required
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Vixen Optics SD81S Overview

  • 1Description

Ideal for visual observation as well as prime focus, eyepiece projection, and afocal imaging astrophotography techniques, the Vixen Optics SD81S 81mm f/8 ED APO Refractor Telescope is an ideal addition to an amateur astronomer or photographer's kit.

Optically, Vixen outfitted the SD81S with FPL53 extra-low dispersion (ED) glass, in a fully multi-coated apochromatic lens system that corrects for both spherical and chromatic aberrations, astigmatism, and off-axis comas. This correction creates a wide flat field of view without distortion and removes the blue-tinted "halo" effect for true high-contrast color transmission. Threads on the drawtube allow direct connection of T-rings and other camera mounts.

Included with the the optical tube assembly (OTA) is a flip-mirror diagonal with dual 1.25" holders. The light path can be directed to the upper holder with the mirror in the Up position, and to the rear holder by flipping it down. For visual observation, the mirror can hold two eyepieces to allow easy changes from low to high magnification. When using it for imaging, the camera or imaging system is placed in the back, and an eyepiece can be attached at the top to check alignment and tracking between exposures.

Vixen offers the OTA without a mount and tripod for users who already have a reliable support system, but include a mounting ring assembly and a Vixen-style dovetail plate to make it compatible with a wide variety of mounts. An integrated carry handle makes se tup and break down easier and safer.

Optical Tube
  • Designed to capture the entire field of view of a DSLR camera with a full-frame image sensor
  • 81mm aperture draws in enough light to view the moon, planets, and bright deep sky objects without excessive bulk or weight
  • Fast f/8 focal ratio makes it ideal for long exposure astrophotography and imaging
  • 625mm focal length produces a moderate magnification potential without being too long
  • Refractor-style light path delivers clear and sharp image
  • FPL53 extra-low dispersion glass corrects chromatic aberration across the entire visual spectrum for clearer views and images without halos or fringing
  • Apochromatic lens configuration eliminates spherical aberrations that cause distortion at the edges of the field of view, and further corrects chromatic aberrations
  • Anti-reflection multi-coated optics improve light transmission to produce bright and clear high-contrast images with accurate color fidelity
  • Resolution: 1.43 arcsec
  • 60mm and 42mm adapter threads accept T-ring and camera mounts for astrophotography and imaging
  • Optical tube assembly only — mount head and tripod required for proper use
  • Vixen-style dovetail plate is compatible with a wide variety of mount heads
  • Tube rings enable the OTA orientation to be adjusted for proper balance and to avoid interference with mount and accessories
  • Integrated carry handle for a secure set up and break down
  • Weight: 7.2 lb
Included Accessories
Flip-mirror diagonal:
  • Flip mirror down to direct light straight back or move it up to use upper holder
  • Enables the use of two eyepieces or a guider eyepiece and imaging system
  • 1.25" holders are compatible with a wide variety of eyepieces and accessories
XY Dot Finder:
  • Unmagnified view makes finding alignment stars fast and star-hopping navigation easy
  • Projects a simple red dot into the view, which won't obstruct small stars, planets, or other objects
  • Rheostat controls the variable intensities with 11 levels; allows dot to be seen without affecting night-adjusted vision
  • Runs on one included CR2032 battery
In the Box
Vixen Optics SD81S 81mm f/8 ED APO Refractor Telescope (OTA Only)
  • Mounting Tube Rings
  • Diagonal Flip-Mirror
  • Dovetail Mounting Plate
  • Carry Handle
  • XY Dot Finder
  • Limited 5-Year Warranty
  • Table of Contents
    • 1Description

    Vixen Optics SD81S Specs

    Optical Design Refractor
    Aperture 81mm
    Focal Length 625mm
    Focal Ratio f/7.7
    Eyepiece Barrel Diameter 1.25"
    Diagonal Flip-mirror, dual-eyepiece holder
    Finderscope Red dot
    Tripod None
    Mount Type None
    Power Source None
    Optical Tube Dimensions 23.0 x 3.5" / 58.5 x 9.0 cm
    Weight 7.2 lb / 3.3 kg
    Packaging Info
    Package Weight 10.65 lb
    Box Dimensions (LxWxH) 24.5 x 11.7 x 8.3"

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