Celestron C11 SCT OTA - CGE Dovetail

The Celestron C11-A delivers impressive light-gathering power in a rugged and portable aluminum optical tube. At just 24 inches long and weighing 27.5 pounds, it can still be transported to dark-sky locations and set up by one person. Its powerful optics make it an excellent choice for serious visual observing and astrophotography. The C11 provides high-contrast views and performs exceptionally well at high magnifications. Celestron’s patented StarBright® XLT optical coatings enhance light transmission and contrast, producing brighter deep-sky images and shorter exposure times while revealing fine details on the Moon, planets, galaxies, and nebulae. With an f/10 focal ratio and Fastar compatibility, the C11 offers added flexibility for astrophotography. It can also be paired with an optional f/6.3 focal reducer for additional imaging possibilities. The C11-A features a CGEM-style dovetail bar, allowing it to be mounted on a wide range of computerized telescope mounts. With its combination of powerful optics, portability, and imaging versatility, the C11-A is designed to take both visual observing and astrophotography to the next level.

Fastar Technology

In 1997, CCDs were making a name for themselves in the astrophotography world, quickly supplanting traditional film photography thanks to their speed and convenience. This was the year that Celestron joined forces with the Santa Barbara Instruments Group (SBIG) to produce Fastar, a revolutionary add-on to Celestron’s hugely popular Schmidt-Cassegrain (SCT) optical system. With Fastar, the SCT’s secondary mirror can be removed and replaced with a field-flattening lens assembly (sold separately by third party manufacturers) so that a CCD camera can be used in the front of the telescope at the f/2 focus of the instrument’s primary mirror. The potential of the Fastar system is staggering: exposures are 25 times shorter than if the camera was placed at the instrument’s native f/10 focus. Imagers can capture galaxies and nebulae with exposures of just 30 seconds.

StarBright XLT coatings

StarBright XLT is Celestron’s revolutionary optical coating system. It consistently outperforms all other coatings in the commercial telescope market. There are three major components that make up our StarBright XLT high-transmission optical system design:

• Unique enhanced multi-layer mirror coatings made from precise layers of aluminum, SiO2 (quartz), TiO2 (titanium dioxide), and SiO2 (silicon dioxide). Reflectivity is fairly flat across the spectrum, optimizing it for both imaging and visual observing.
• Multi-layer anti-reflective coatings made from precise layers of MgF2 (magnesium fluoride) and HfO2 (hafnium dioxide). Hafnium—a rare element that costs nearly $2,000 per kilogram—gives us a wider band pass than the titanium used in competing coatings.
• High-transmission water white glass is used instead of soda lime glass for the corrector lens. Water white glass transmits about 90.5% of light without anti-reflective coatings; that’s 3.5% better than uncoated soda lime glass. When water white glass is used in conjunction with StarBright XLT’s anti-reflective coatings, the average transmission reaches an astonishing 97.4.

Features

• 11" Schmidt-Cassegrain Optical Tube Assembly (OTA)
• Features Celestron's premium patented StarBright XLT optical coatings
• 2800mm focal length (f/10)
• Fastar compatible
• Tube constructed of durable and lightweight aluminum
• Includes: 40mm eyepiece (70x), 9x50 optical finderscope, star diagonal, 1.25” visual back, CGEM-style dovetail bar