Radian AP 61/275 Raptor OTA

Description

Ohara FPL-53 premium extra-low dispersion glass powers the Radian AP 61/275 Raptor OTA compact apochromatic refractor optical tube assembly. Designed in the United States and manufactured in Taiwan by Radian Telescopes, this ultra-fast f/4.5 astrograph features a 61mm (2.40 inches) aperture and a 275mm focal length, delivering 1.90 arcsecond Dawes resolving power and reaching magnitude 11.5 for wide-field astrophotographers.

The Radian AP 61/275 Raptor OTA incorporates an air-spaced triplet lens assembly with an Ohara FPL-53 synthetic fluorite center element, ultra-wideband fully multi-coated optics, and a built-in dedicated field flattener lens. Its lightweight aluminum body features a 2.5-inch dual-speed rack and pinion focuser with a 10:1 micro-drive and a 360-degree rotator. Weighing just 1.80 kg (3.97 lbs), it delivers pinpoint stars across full-frame sensors.

Key Features of Radian AP 61/275 Raptor OTA

Crafted for ultra-wide-field travel astrophotography, this 61mm Radian Telescopes Raptor refractor pairs an FPL-53 triplet objective with an integrated field flattener. Its compact 275mm focal length and fast f/4.5 optical speed capture expansive deep-sky nebulae across full-frame sensors with zero chromatic fringing.

• 61mm (2.40 inches) aperture with 275mm focal length and fast f/4.5 optical speed
• Three-element air-spaced triplet objective featuring Ohara FPL-53 ED glass core
• Built-in dedicated field flattener lens for full-frame sensor illumination
• Ultra-wideband fully multi-coated lens matrix for maximum light transmission
• 2.5-inch dual-speed rack and pinion focuser with 10:1 micro-focus reduction
• Integrated 360-degree camera rotator for effortless framing composition
• Hexagonal tube rings with dual finder mounting shoes and universal dovetail bar
• Lightweight aluminum body weighing only 1.80 kg with padded travel case included

FPL-53 Triplet Optics & Built-In Dedicated Flattener

The triplet optical prescription combines Ohara FPL-53 fluorite glass with an internal flattener element, producing a flat, color-free focal plane out to the corners of full-frame sensors. With zero central obstruction (0.00%), this fast Radian refractor supports magnifications from 9x up to 122x.

2.5-Inch Focuser, 360° Rotator & Hexagonal Rings

Travel imaging requires rigid mechanical precision in a compact chassis. The Radian Raptor 61 features a 2.5-inch rack and pinion focuser with 10:1 micro-reduction and a built-in 360-degree camera rotator. Equipped with innovative hexagonal tube rings and dual finder shoes, mounting guide scopes and accessories is simple.

• 2.5-inch dual-speed rack and pinion focuser with 360-degree position rotator
• Hexagonal tube ring array with dual mounting shoes for autoguiders and controllers
• Universal Vixen/Losmandy dovetail plate and custom padded travel case included

Radian Telescopes Raptor 61 Warranty

The Radian AP 61/275 Raptor OTA is backed by a 1-year limited warranty against material and manufacturing defects. The factory package contains the Raptor 61 triplet refractor, built-in dedicated field flattener lens, hexagonal tube rings, universal dovetail bar, front and rear dust caps, and a premium padded travel case.