TS Optics AP 125/975 OTA

Description

Operating at a 975mm focal length with 0.93 arcseconds theoretical resolving power, the TS Optics AP 125/975 OTA is an apochromatic doublet refractor telescope built for high-contrast lunar and planetary observation. Sized with an unobstructed 125mm (4.92 in) clear aperture and an f/7.8 focal ratio, this optical tube assembly gathers light to visual magnitude 13.1, splitting close double stars and recording long-focus deep-sky astrophotography targets on large-format cameras.

The optical system features an air-spaced Lanthanum-ED doublet objective pairing Ohara FPL-53 glass with lanthanum crown elements, treated with broadband fully multi-coated (FMC) anti-reflection layers and an unobstructed 0% central profile. Built inside an aluminum chassis measuring 850mm retracted and 980mm extended with a 150mm outer dew shield diameter, the assembly supplies 150mm of back focus from the rear 2-inch visual back. Fitted with a 2.5-inch dual-speed rack-and-pinion focuser, an M63x1 rear thread, and an integrated 360-degree rotator, this 7.57 kg (16.69 lbs) refractor illuminates a 44mm full-frame image circle when paired with dedicated correctors.

Key Features of TS Optics AP 125/975 OTA

Built for solar system detail auditing and high-magnification planetary viewing, this 125mm doublet combines an Ohara FPL-53 lens with a rotatable 2.5-inch rack-and-pinion focuser. CNC-machined split tube rings, a top utility carrying handle, and a standard Vixen dovetail bar provide rigid structural mounting on medium-payload equatorial mounts.

• 125mm (4.92 in) clear aperture with 975mm focal length and f/7.8 optical speed
• Air-spaced ED doublet objective featuring Ohara FPL-53 and lanthanum optical glass
• Broadband fully multi-coated (FMC) optical layers with an unobstructed 0% central profile
• 2.5-inch dual-speed rack-and-pinion focuser 1:10 with integrated 360-degree rotator and M63x1 thread
• Generous 150mm back focus distance measured from the rear 2-inch visual back
• Corrected 44mm full-frame image circle when paired with dedicated flattener or reducer
• CNC-machined tube rings with 44mm Vixen-style dovetail bar and top utility handle
• Step-down 2-inch to 1.25-inch visual adapter, finder base, and retractable dew shield included

Ohara FPL-53 & Lanthanum Doublet Color Control

The combination of an Ohara FPL-53 Super ED element and a high-refraction lanthanum mating element cancels secondary chromatic aberration while maintaining rapid thermal acclimatization compared to larger triplets. The unobstructed 125mm optical path delivers high contrast on Jupiter’s cloud belts and lunar rilles across practical magnifications from 17.9x up to 250x.

Heavy-Duty 2.5-Inch Rack-and-Pinion Drive & M63 Coupling

Critical focusing at f/7.8 is managed through a 2.5-inch rack-and-pinion focuser featuring a 1:10 fine-focus mechanism, an M63x1 threaded rear interface, and an integrated 360-degree field rotator. The optical tube locks securely into CNC-machined rings with a top carrying handle, weighing 7.57 kg for manageable field transportation.

• 2.5-inch dual-speed rack-and-pinion focuser with 1:10 micro-reduction for smooth focusing control
• Direct M63x1 rear camera thread with integrated 360-degree rotator for camera framing
• CNC-machined aluminum tube rings with top utility handle for balanced mount attachment

TS Photoline Doublet ED Series Guarantee

The TS Optics AP 125/975 OTA is backed by a 2-year limited warranty against material and manufacturing defects. The complete factory package contains the 125/975 ED Doublet OTA, CNC-machined tube rings, Vixen-style dovetail bar, top carrying handle, 2-inch to 1.25-inch adapter, and a finder base.