Vixen SD81S II f/7.72 Doublet Refracting OTA Telescope



Astroimaging Options:

  • Prime Focus
  • Eyepiece Projection
  • Afocal Photography


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  • Regular price $1,980.00
  • $1,099.00
  • You save: $881.00 (44%)

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Vixen SD81S II f/7.72 Doublet Refracting OTA Telescope

The SD81S II OTA is an Apochromatic Refractor Telescope

It features high-performance Super ED Glass(SD) made of leading-edge FPL53 glass to deliver extremely clear and sharp images by eliminating color aberration. This SD glass is designed to gather all g-ray (purple), C-ray (red), F-ray (blue), d-ray (yellow), and e- ray (green) to about a "0" value, making excellent lens material which reduces chromatic aberration over all colors.

The light baffle positions in the drawtube are arranged to take advantage of the entire field of view of a DSLR camera with a full frame image sensor. When used in combination with the new optional SD Reducer HD Kit or SD Flattener HD Kit, you will have a 44 mm image circle with full-format DSLR cameras.

Vixen SD81S II Refractor Telescope OTA-long

The Reducer DH, sold separately, includes the SD Flattener DH and is essential for wide field astrophotography with the SD Scopes.

Eyepieces are also sold separately.


Additional Information:

  • Coating :Multi Coating
  • Finder Scope: Red Dot Finder
  • Adapter Thread: 60 mm/ 42 mm for T-Ring
  • Visual Back : 50.8 mm and 31.7 mm Push fit with the supplied flip mirror diagonal



Aperture81 mm (3.25")
Camera/Eyepiece Connection2" Nosepiece
Dawes Limit1.43 arcseconds
Focal Length625 mm
Focal Ratiof/7.72
Highest Magnification162x
Light Gathering Power134x
Limiting Magnitude13.3
Optical DesignDoublet
Tube Diameter90mm
Tube Length585mm
Tube Weight7.2 lbs



Accessories Included:

  • Tube Rings
  • Flip Mirror Diagonal
  • Dovetail Plate
  • Red Dot Finder
  • Carry Handle