Vixen VC200L VISAC C 200/1800 OTA

Description

Corrected internally with an integrated three-element field flattener in the drawtube, the Vixen VC200L VISAC C 200/1800 OTA is a sixth-order aspheric catadioptric cassegrain telescope optical tube assembly built for flat-field deep-sky astrophotography. Operating at an f/9.0 focal ratio with an 1800mm focal length, this Japanese 200mm (7.87 in) aperture instrument delivers a 0.58 arcseconds theoretical resolving power and reaches magnitude 13.3, capturing faint extragalactic targets and coma-free star field photometry.

The optical system features a catadioptric Cassegrain layout combining a sixth-order aspherical primary mirror, a convex secondary mirror, and an integrated three-element field corrector lens inside the focuser drawtube, treated with multi-layer dielectric high-reflectivity mirror coatings and fully multi-coated corrector optics with a 35.5% central obstruction by diameter (12.6% by area). Built inside an aluminum chassis measuring 600mm in length with a 232mm outer tube diameter, the assembly supplies 142.9mm of back focus from the rear mechanical thread (63.5mm from optional dedicated 0.71x reducers). Supported by a 2-inch heavy-duty dual-speed rack-and-pinion focuser with dual knobs, a tension brake, and M60 accessory threads, this 6.00 kg (13.23 lbs) optical tube covers a 42mm full-frame image circle free of coma and field curvature.

Key Features of Vixen VC200L VISAC C 200/1800 OTA

Engineered for high-resolution deep-sky imaging, this 200mm VISAC catadioptric system pairs a sixth-order aspherical primary mirror with a triplet corrector to deliver a flat photographic plane across full-frame sensors. Its direct-mounted Vixen dovetail rail, top carrying handle, and 7×50 finderscope provide a rigid imaging platform for equatorial mounts.

• 200mm (7.87 in) clear aperture with 1800mm focal length and flat-field f/9.0 optical speed
• VISAC catadioptric design with sixth-order aspherical primary and integrated triplet corrector
• Precision annealed low-expansion mirror substrates with multi-layer dielectric coatings
• Moderate central obstruction of 35.5% by diameter (12.6% by area) for balanced image contrast
• 2-inch heavy-duty dual-speed rack-and-pinion focuser with tension brake and M60 threads
• Generous 142.9mm back focus distance from rear mechanical thread (63.5mm with 0.71x reducer)
• Corrected 42mm full-frame image circle delivering coma-free and astigmatism-free star profiles
• Vixen-style dovetail rail mounted to heavy aluminum castings, top handle, and 7×50 finder included

Sixth-Order Aspheric Primary & Internal Triplet Corrector

The unique VISAC optical geometry utilizes a specialized sixth-order aspheric primary mirror combined with a three-element corrector group in the drawtube to eliminate coma, spherical aberration, and field curvature out to the edges of 35mm and full-frame sensors. Low-expansion mirror substrates preserve wavefront accuracy during temperature drops, supporting practical visual magnifications from 28.6x up to 400x.

Precision Drawtube Drive & Direct M60 Reducer Interface

Focusing stability under heavy imaging trains is delivered through a 2-inch dual-speed rack-and-pinion focuser featuring dual knobs, an adjustable tension brake, and direct M60 accessory threads for dedicated optical reducers. The dovetail bar is bolted directly to heavy-duty front and rear aluminum tube castings, while the 6.00 kg optical tube balances securely on mount saddles via its top carrying handle.

• 2-inch dual-speed rack-and-pinion focuser with mechanical tension brake to prevent drawtube slip
• Direct M60 threaded connection for rigid mechanical coupling of dedicated focal reducers
• Integrated Vixen dovetail rail bolted to rigid aluminum castings for high torsional stability

Vixen VISAC Catadioptric Series Five-Year Warranty

The Vixen VC200L VISAC C 200/1800 OTA is backed by a 5-year limited warranty against material and manufacturing defects. The complete factory package contains the VC200L VISAC optical tube, integrated triplet field corrector, Vixen dovetail rail, top carrying handle, and a 7×50 optical finderscope with bracket.