Vixen SD115S AP 115/890 OTA

Description

Resolve subtle Jovian cloud textures and split close binary systems through the Vixen SD115S AP 115/890 OTA observatory-grade apochromatic doublet refractor optical tube assembly. Operating at an f/7.7 focal ratio with an 890mm focal length, this 115mm (4.53 in) clear aperture telescope delivers a 1.01 arcseconds theoretical resolving power and reaches magnitude 12.1, gathering light for high-contrast lunar observing, high-power double-star astrometry, and false-color-free deep-sky astrophotography.

The optical system features an air-spaced Super Low Dispersion doublet objective pairing an FPL-53 Super ED element with eco-friendly mating glass, treated with ultra-wideband fully multi-coated (FMC) broad-band layers with an unobstructed 0% central profile. Built inside an aluminum chassis measuring 930mm in length with a 125mm outer tube diameter, the assembly supplies 145mm of back focus from the rear mechanical thread (63.5mm from the M60 thread on optional Flattener HD optics). Supported by a 2-inch heavy-duty rack-and-pinion focuser with dual knobs, mechanical tension control, and a direct T-thread and M60 interface, this 4.40 kg (9.70 lbs) refractor covers a 44mm full-frame flat field with dedicated optical correctors.

Key Features of Vixen SD115S AP 115/890 OTA

Designed for demanding visual astronomers and deep-sky imagers seeking large apochromatic light grasp with rapid thermal equilibrium, this 115mm refractor couples FPL-53 glass with a heavy-duty 2-inch focuser. Heavy-duty tube rings, a top carrying handle, a standard Vixen dovetail plate, and a dual-port flip mirror deliver a rigid, adaptable platform for equatorial mounts.

• 115mm (4.53 in) clear aperture with 890mm focal length and versatile f/7.7 optical speed
• Air-spaced SD doublet objective utilizing FPL-53 Super ED glass and eco-friendly mating glass
• Ultra-wideband fully multi-coated broad-band anti-reflection optics with 0% central obstruction
• 2-inch heavy-duty rack-and-pinion focuser with tension control and direct T-thread/M60 interface
• Generous 145mm back focus distance from rear mechanical thread (63.5mm from Flattener HD)
• Corrected 44mm full-frame flat field image circle when paired with optional HD correctors
• Heavy tube mounting rings with standard Vixen dovetail plate and top carrying handle
• Retractable dew shield, red dot finder, and dual-port flip mirror diagonal included

Large-Aperture Super Dispersion Doublet Performance

The air-spaced doublet pairs an FPL-53 Super ED element with precision Eco-Glass to suppress chromatic dispersion across broad spectral bandwidths. Because it employs two optical elements rather than three, thermal cool-down occurs rapidly in falling ambient temperatures, supporting practical visual magnifications from 16.4x up to 230x.

Direct M60 Threaded Coupling & Mechanical Tension Brake

Holding imaging camera trains without drawtube flexure is delivered through a 2-inch rack-and-pinion focuser featuring dual focus knobs, an adjustable tension brake, and direct M60 accessory threading for dedicated flatteners and reducers. The included dual-port flip mirror diagonal facilitates seamless transitions between visual inspection and camera acquisition, while the 4.40 kg optical tube balances securely in CNC rings.

• 2-inch rack-and-pinion focuser with tension adjustment to eliminate drawtube slip under accessory loads
• Integrated dual-port flip mirror diagonal for instant switching between eyepiece and camera setups
• Heavy-duty aluminum tube rings with top carrying handle for balanced mount transport

Vixen Flagship SD115S Refractor Series Warranty

The Vixen SD115S AP 115/890 OTA is backed by a 5-year limited warranty against material and manufacturing defects. The complete factory package contains the SD115S apochromatic OTA, retractable dew shield, heavy tube mounting rings, Vixen dovetail plate, top carrying handle, red dot finder, and a dual-port flip mirror diagonal.