Astronomy Specialist

ZENITHSTAR 81 F/6.9 APO DOUBLET

$1,499.00

Color
Gold
Red
Quantity
- +

 

The William Optics ZenithStar 81 is a two element apochromatic refractor with a focal ratio of f/6.9 and a focal length of 559mm. Utilizing FPL-53 synthetic fluorite glass, this telescope provides excellent aberration correction.

The 2.5" 10:1 rack & pinion focuser is smooth, stable and reliable, providing no slippage over long imaging sessions. The new CNC-machined and anodized handle bar with Vixen-style saddle is perfect for attaching a guide scope or other accessories. The ZenithStar 81 also includes William Optics' innovative clear Bahtinov mask integrated into the lens cap.

For best imaging results, it is recommended to pair the ZenithStar 81 with its matching Flat6AIII 0.8x field flattener.


 

Optical design

Apochromatic doublet

Objective diameter

81 mm

Focal length

559 mm

Focal ratio

f/6.9

Image circle

44.3 mm (with Flat6AIII field flattener)

Compatible flattener

William Optics Flat6AIII

Mount attachment

210 mm Vixen-style/Arca-Swiss dovetail bar

Focuser

Rack & pinion dual speed (10:1) 2.5" diameter

Camera connection

M63 x 1, 2"

Backfocus

60.2 mm (with flattener/reducer)

Tube weight

3.53 kg (including accessories)

Tube length

460 mm (fully retracted), 560 mm (fully extended)

Tube diameter

TBA

Dew shield diameter

TBA

SKU

WO-A-Z81GD (Gold), WO-A-Z81RD (Red)

 

 

  • ZenithStar 81
  • Lens cap with Bahtinov mask
  • Vixen-style saddle handle bar
  • 210 mm Vixen-style dovetail bar
  • Soft carry case

Customer Reviews

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P
Paul Larkin
Does just what I want

I bought the Z81 with the Dura Bright 2" diagonal (into which I put a 1.25" Baader 8-24 Hyperion zoom eyepiece) and later, Flat6Aiii, L-Pro filter and EOS-R adaptor.

It's early days and there have been a few good nights in Bortle 6 skies. So far, really happy and I can only see it getting better. Jupiter is crisp and bands are clearly visible; Saturn is crisp and gorgeous, as is the moon.

Tried M8(Lagoon)/M20(Trifid) with DSLR and L-Pro filter. For a first attempt at AP, was super pleased with the result (see uncropped image).

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