The Celestron C8 OTA is an 8" Schmidt-Cassegrain optical tube featuring StarBright XLT coatings for high contrast and transmission. The Celestron C8-A is the direct (but much improved) descendent of Celestron’s revolutionary C8 that transformed the hobby of astronomy when it was unveiled in 1970. This rugged aluminium optical tube is only 432mm long and weighs just 5.67kg, making it easy to transport and set up. The views are much more impressive than what you’d expect from such a compact instrument. The tube offers a focal length of 2032mm and a focal ratio of f/10, with the added versatility of Fastar/Hyperstar (sold separately). The C8 is equipped with Celestron’s patented StarBright® XLT optical coatings, which visibly increase contrast and light transmission for brighter deep space images and shorter exposure times. With StarBright XLT, you’ll be able to discern subtle details while viewing the Moon and planets as well as faint galaxies and nebulae. The Celestron C8-A can be mounted on a multitude of computerized telescope mounts thanks to its CG-5 style dovetail bar. This iconic optical tube provides the best balance of portability, handling ease, light gathering ability and price ever offered to the amateur astronomer. StarBright XLT is Celestron’s revolutionary optical coating system, consistently outperforming 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 aluminium, 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. With Fastar/Hyperstar compatbility, 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 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. Specifications Optical design Schmidt-Cassegrain Aperture 203.2 mm (8") Focal length 2032 mm Focal ratio f/10 Resolving power 0.57 arc seconds Stellar limiting magnitude 14 Light gathering power 843 times the human eye Central obstruction diameter 64 mm (31% of aperture diameter) Wavelength range 400 - 750 nm Optical coatings StarBright XLT Backfocus from rear flange 133.35 mm (105 mm with optional reducer) Mount attachment CG-5 dovetail plate Threads 2"-24 UNC Tube length 432 mm Tube weight 5.67 kg Tube diameter 238 mm SKU CE-91020-XLT Items included C8 OTA CG-5 dovetail 6 x 30 finderscope 1.25" star diagonal 25mm Plossl 1.25" eyepiece
