William Optics FluoroStar AP 132/925 Red OTA

Description

Eliminating secondary spectrum chromatic fringing across large sensor formats, the William Optics FluoroStar AP 132/925 Red OTA is an observatory-class apochromatic triplet refractor optical tube assembly built for deep-sky astrophotography. Operating at an f/7.0 focal ratio with a 925mm focal length, this 132mm (5.20 in) aperture telescope delivers a 0.88 arcseconds theoretical resolving power and reaches magnitude 13.3, collecting photons across faint star clusters, emission nebulae, and planetary discs.

The optical system features an air-spaced Super APO triplet objective housed in a CNC temperature-compensated lens cell, incorporating an Ohara FPL-53 Super ED center element paired with rare-earth lanthanum mating glasses, treated with ultra-high transmission broadband multi-coatings (STM) with an unobstructed 0% central profile. Built inside an aluminum chassis measuring 780mm retracted and 940mm extended with a 168mm outer dew shield diameter, the tube supplies 170mm of back focus from the rear mechanical thread (55mm standard from M48/M68 flattener threads). Supported by a 3.3-inch heavy-duty dual-speed rack-and-pinion focuser with red accents and a 360-degree rotator, this 9.00 kg (19.84 lbs) refractor illuminates a 44mm full-frame and medium-format field when paired with dedicated Flat68III or Flat7A correctors.

Key Features of William Optics FluoroStar AP 132/925 Red OTA

Built for demanding astrophotographers and planetary visual observers, this 132mm triplet refractor couples certified FPL-53 optics with an oversized 3.3-inch rack-and-pinion focuser. Heavy CNC mounting rings, a 75mm Losmandy-style dovetail bar, a red top saddle handle with a guiding slot, and an integrated Bahtinov focus mask cap provide dependable mechanical stiffness under heavy loads.

• 132mm (5.20 in) clear aperture with 925mm focal length and versatile f/7.0 optical speed
• Air-spaced Super APO triplet objective with Ohara FPL-53 and lanthanum rare-earth glasses
• Ultra-high transmission broadband multi-coatings with certified Strehl ratio of 0.95 or greater
• 3.3-inch heavy-duty dual-speed rack-and-pinion focuser 1:10 with red accents and 360-degree rotator
• Generous 170mm rear back focus distance (55mm standard from M48/M68 flattener thread)
• Corrected 44mm image circle covering full-frame and medium format with dedicated correctors
• Heavy CNC tube rings with 75mm Losmandy-style dovetail bar and red top saddle handle
• Patented clear Bahtinov focus mask cap and rotatable visual back included in package

STM Broadband Multi-Coatings & Strehl 0.95 Optics

The air-spaced triplet lens cell pairs an Ohara FPL-53 Super ED center element with rare-earth lanthanum glass to eliminate secondary spectrum chromatic aberration across the optical path. Certified by a factory interferometric test report verifying a Strehl ratio of 0.95 or higher, the unobstructed 132mm optical path preserves high contrast, supporting practical visual magnifications from 18.9x up to 264x.

CNC Saddle Handle Mechanics & Dual-Speed Tuning

Holding heavy CCD and CMOS imaging trains without drawtube flexure is delivered through a 3.3-inch rack-and-pinion focuser featuring a 1:10 micro-reduction drive, an integrated 360-degree field rotator, and an engraved millimeter scale. The red CNC saddle handle accommodates guide scopes and accessories, while heavy-duty mounting rings keep the 9.00 kg tube balanced on mount saddles.

• 3.3-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

William Optics FluoroStar Red Edition Warranty

The William Optics FluoroStar AP 132/925 Red OTA is backed by a 2-year limited warranty against material and manufacturing defects. The complete factory package contains the FLT132 Red OTA, patented Bahtinov focus mask integrated cap, CNC heavy tube rings, Losmandy dovetail bar, top saddle handle, and a rotatable visual back.