William Optics ZenithStar 81 WIFD Gold OTA — 81 mm doublet apochromat This refractor provides a 559 mm focal length at f/6.9. The manufacturer lists a 45 mm image circle and optional correctors for photographic use.
Manufacturer model: William Optics ZenithStar 81 WIFD Gold OTA · Specifications checked against manufacturer data on 2026-11-03
This refractor provides a 559 mm focal length at f/6.9. The manufacturer lists a 45 mm image circle and optional correctors for photographic use.
The WIFD rack and pinion focuser provides 77 mm travel. Connections comprise M92 rotator; M92 to M63 adapter.
Manufacturer-listed options: Flat6AIII 0.8x. Each combination has a specific spacing and adapter arrangement; see the individual settings in the specifications. A corrector is an optional accessory.
Tube length is 526–607 mm and OTA weight is 3.55 kg. Total weight is 4.56 kg.
William Optics manufacturer manual
Prime-lens telescope: corrector compatibility and spacing are model-specific. Optional correctors are listed, not assumed included; corrector adapters may be required.
| Flat6aiii spacing | 60.2 mm backfocus; 5.2 mm adjustment |
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William Optics ZenithStar 81 WIFD Gold OTA — 81 mm doublet apochromat This refractor provides a 559 mm focal length at f/6.9. The manufacturer lists a 45 mm image circle and optional correctors for photographic use.
Manufacturer model: William Optics ZenithStar 81 WIFD Gold OTA · Specifications checked against manufacturer data on 2026-11-03
