William Optics Super ZenithStar 73 AP 73/430 Gold OTA

Description

Capture high-contrast deep-sky astrophotography targets and daytime wildlife scenes with the William Optics Super ZenithStar 73 AP 73/430 Gold OTA apochromatic doublet refractor optical tube assembly. Operating at a fast f/5.9 focal ratio with a 430mm focal length, this 73mm (2.87 in) clear aperture instrument delivers a 1.59 arcseconds theoretical resolving power and reaches magnitude 12.0, collecting photons for wide-field rich-field visual scanning, terrestrial spotting, and grab-and-go deep-sky imaging.

The optical system features an air-spaced extra-low dispersion doublet objective combining Ohara FPL-53 Super ED glass with a matched lanthanum element, treated with fully multi-coated STM broad-band anti-reflection coatings with an unobstructed 0% central profile. Built inside an aluminum chassis measuring 315mm retracted and 375mm extended with a 92mm outer dew shield diameter, the tube assembly supplies 140mm of back focus from the rear visual back (55mm standard from M48 threads on optional Flat73A or Flat73R correctors). Supported by a 2.5-inch dual-speed rack-and-pinion focuser with a 1:10 reduction gear, a 360-degree field rotator, and gold anodized accents, this 2.50 kg (5.51 lbs) refractor illuminates a 44mm full-frame image circle when paired with dedicated correctors.

Key Features of William Optics Super ZenithStar 73 AP 73/430 Gold OTA

Engineered for portable deep-sky astrophotography and rich-field visual astronomy, this 73mm doublet couples Ohara FPL-53 optics with an oversized 2.5-inch rack-and-pinion focuser. CNC-machined split tube rings, a reversible Vixen and Arca-Swiss dovetail bar, a gold top saddle handle with a guiding slot, and an integrated Bahtinov mask cap deliver an adaptable field platform.

• 73mm (2.87 in) clear aperture with 430mm focal length and fast f/5.9 optical speed
• Air-spaced ED doublet objective featuring Ohara FPL-53 and lanthanum glass elements
• Fully multi-coated STM broadband anti-reflection coatings with 0% central obstruction
• 2.5-inch dual-speed rack-and-pinion focuser 1:10 with gold accents and 360-degree field rotator
• Generous 140mm back focus distance from visual back (55mm from M48 thread on Flat73A/R)
• Corrected 44mm full-frame image circle when paired with dedicated Flat73A or Flat73R optics
• Reversible Vixen/Arca-Swiss dovetail bar with CNC tube rings and gold top saddle handle
• Patented clear Bahtinov focus mask cap and top saddle handle with guiding slot included

Ohara FPL-53 & Lanthanum ED Doublet Color Purity

Pairing an Ohara FPL-53 Super ED element with a high-refraction lanthanum mating substrate controls chromatic dispersion across broad spectral bands, eliminating false-color fringing on bright lunar rims and stars. The unobstructed 73mm optical path delivers crisp contrast while supporting practical visual magnifications from 10.4x up to 146x.

Two-Point-Five-Inch Rack-and-Pinion Drive & Gold Accents

Holding camera equipment without drawtube tilt is managed by a 2.5-inch rack-and-pinion focuser featuring a 1:10 micro-reduction gear, an integrated 360-degree field rotator, and an engraved focal position scale. The gold CNC saddle handle accommodates guide scopes, while the reversible dovetail bar clamps onto standard Vixen or Arca-Swiss saddles.

• 2.5-inch dual-speed rack-and-pinion focuser with 1:10 micro-reduction to eliminate drawtube flexure
• Built-in 360-degree camera field rotator for rapid target orientation without losing focus
• Patented clear Bahtinov focus mask integrated into the metal lens cap for precise focus acquisition

ZenithStar 73 Gold Series Factory Warranty

The William Optics Super ZenithStar 73 AP 73/430 Gold OTA is backed by a 2-year limited warranty against material and manufacturing defects. The complete factory package contains the ZenithStar 73 Gold OTA, integrated patented Bahtinov focus mask cap, CNC tube rings, dual-sided dovetail bar, and a top saddle handle with guiding slot.