Celestron C9.25 SCT OTA - CGE Dovetail

The Celestron C9.25 features a 9.25-inch aperture and 2350mm focal length, offering an excellent balance of size, performance, and portability. Its rugged aluminum optical tube is only 22 inches long and weighs 20 pounds, making it relatively easy to transport and set up while delivering impressive views. The C9.25 has an f/10 focal ratio and also offers Fastar compatibility for added imaging versatility. Equipped with Celestron’s patented StarBright® XLT optical coatings, the C9.25 provides improved light transmission and contrast for brighter deep-sky images and shorter exposure times. These enhanced optics also help reveal subtle details on the Moon and planets, as well as faint galaxies and nebulae. The C9.25 can be paired with a wide range of computerized telescope mounts using its CGEM-style dovetail bar. With its combination of portability, handling ease, light-gathering capability, and performance, the C9.25 offers a well-balanced optical tube for amateur astronomers.

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.