Apertura 12" f/8 Ritchey-Chretien Optical Tube

Apertura 12” f/8 Ritchey Chretien Truss Tube OTA

Ritchey-Chretien telescopes do not use any lenses in their design.They instead consist of a concave hyperbolic primary and a convex hyperbolic secondary mirror. This design provides superb image correction across the entire field and very sharp images on-axis. Optical testing is done several times throughout the manufacturing process. Then, before the optical set is mounted in an OTA, it is tested again and hand-corrected if necessary to bring it up to the advertised wavefront.

Using a true Ritchey-Chretien telescope for astrophotography has been the dream of many an amateur astronomer, but making that dream come true used to be nearly impossible because of the price tag. This Apertura 12" Ritchey-Chretien is a quality, large aperture RC telescope that won’t break the bank, they have opened up the possibility of that professional-style, dream telescope to a higher percentage of the amateur astrophotography population. The 12” f/8 RC OTA can illuminate an approximate 30 mm field diameter. This is a true Ritchey, so you do not have to worry about chromatic aberrations, coma, false color, or the need to add a field flattener/corrector to the mix!

The Apertura 12” RC has a 1/12th wave or better primary mirror. The mirror is made of quartz and then topped with a highly reflective (96%) enhanced protected aluminum coating that also protects the optics against sleeks and scratches. Quartz has a coefficient of thermal expansion many times lower than most other optical substrates. This helps the precision-manufactured optics hold their shape far better than other substrates through the changing temperatures of an imaging session. The primary is mounted in a fixed mirror cell, eliminating the problem of image shift. The secondary mirror is also created out of the same materials as the primary (that is not always the case!) and is mounted in a fully adjustable cell for ease of collimation.

About the Carbon Fiber Truss Tube Design

Carbon fiber has an amazing strength to weight ratio, and it cools down like a champ. The 12” f/8 OTA is made of carbon truss tubes allowing the optical tube to weigh in at only 44 lbs. The inside of the optical tube includes a computer-optimized baffle system to eliminate stray light. Three small fans located at the back of the telescope help it reach ambient temperature in a flash.

About the 3” Crayford Focuser

The Apertura 12” RC comes with a 3” Crayford Focuser. The focuser rides on a stainless steel track, or monorail when you rack the focus in or out. This updated design feature keeps the focuser from twisting or bending when you have a camera or imaging set-up riding on it. A 10:1 dual speed focusing system allows for both coarse and fine focus, and the focuser can be rotated 360º to help you achieve the proper image orientation.

Apertura 12” f/8 RC Telescope Specifications

• Telescope Design: Ritchey-Chretien

• Aperture: 12” or 304 mm

• Focal Length: 2432 mm

• Focal Ratio: f/8

• Back Focus: 288 mm

• Mirror Material: Low Expansion Quartz

• Coatings: 96% Enhanced Protected Aluminum Coatings

• Central Obstruction: 150 mm

• Tube Material: Carbon Fiber with metal mirror cells

• OTA Weight: 55 lb or 25kg including rails

• OTA Length: 37.8” or 960 mm with focuser

• OTA Diameter: 14” or 356 mm

• Focuser: 3” Dual Speed Crayford

• Focus Travel: +/- 80 mm

• Focuser Clear Aperture: 68 mm

• Dovetail: Losmandy D - Top & Bottom

The Ritchey-Chretien was designed for photographic use, and while you can put an eyepiece in the diagonal and use it visually, you will get less than "stellar" results. It is for this reason that we do not recommend an RC telescope for visual use. If you have any questions or need help choosing a telescope that performs well when used either visually or photographically, please don't hesitate to contact us. Thanks!

This Product Comes with the Apertura Absolute Warranty!

• Two-Year Warranty against product defects.

• Three-Year Accident Replacement Program that begins after your initial 2 year warranty expires.

• Your Apertura Absolute Warranty is transferable.

Download a copy of the Apertura Absolute Warranty for more information on this program, how to make a claim, and why it is important to keep your original receipt and the product's original boxes & packaging!