The Celestron C6-A Optical Tube Assembly (OTA) serves as a versatile piece of equipment, boasting a focal length of 1500 mm and an f/10 focal ratio. It trumps 5-inch Cassegrains by gathering 40% more light, making it an excellent choice for stargazers. The tube also incorporates Celestron's signature StarBright® XLT optical coatings, enhancing both contrast and light transmission. This means you'll capture more detailed images of celestial objects in less time.
As for mounting options, this OTA comes with a CG-5 dovetail bar, which allows it to be easily attached to a variety of computerized telescope mounts. Of course, it's equally compatible with basic manual altazimuth mounts for traditional night sky observation or daytime terrestrial viewing.
What sets the Celestron C6-A apart is its well-rounded nature; it offers a unique blend of portability, user-friendliness, light-collecting prowess, and affordability. This makes it a telescope that can cater to advanced users while remaining as accessible as intermediate and some beginner scopes.
About StarBright XLT Coatings
StarBright XLT represents Celestron's cutting-edge optical coating technology, outdoing anything else currently available in the commercial telescope market. There are three key elements that elevate StarBright XLT's high-transmission optics:
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Multi-layer Mirror Coatings: These are meticulously layered from materials such as aluminum, SiO2 (quartz), TiO2 (titanium dioxide), and SiO2 (silicon dioxide). This results in a spectrum-friendly reflectivity ideal for both imaging and visual observation.
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Anti-Reflective Coatings: Crafted from precise layers of MgF2 (magnesium fluoride) and HfO2 (hafnium dioxide), the latter being a rare and pricey element. These coatings deliver a broader band pass compared to what you'll get with titanium-based coatings.
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Water White Glass: This type of glass is used for the corrector lens, offering superior light transmission—about 90.5% even without anti-reflective coatings. That's a 3.5% advantage over uncoated soda lime glass. When paired with StarBright XLT's coatings, the average light transmission skyrockets to an impressive 97.4%.
For more details on the proprietary StarBright XLT coatings, you can visit Celestron's dedicated page on the subject.
Specifications
| Optical Design: | Schmidt-Cassegrain |
| Aperture: | 150mm (6") |
| Focal Length: | 1500mm (59") |
| Focal Ratio: | f/10 |
| Focal Length of Eyepiece 1: | 25mm (0.98") |
| Magnification of Eyepiece 1: | 60x |
| Finderscope: | 6x30 |
| Star Diagonal: | 1.25" Star Diagonal |
| Optical Tube: | Aluminum |
| Highest Useful Magnification: | 354x |
| Lowest Useful Magnification: | 21x |
| Limiting Stellar Magnitude: | 13.4 |
| Resolution (Rayleigh): | 0.93 arc seconds |
| Resolution (Dawes): | 0.77 arc seconds |
| Light Gathering Power (Compared to human eye): | 459x |
| Secondary Mirror Obstruction: | 56mm (2.2") |
| Secondary Mirror Obstruction by Diameter: | 37% |
| Secondary Mirror Obstruction by Area: | 14% |
| Optical Coatings: | StarBright XLT |
| Optical Tube Length: | 406mm (16") |
| Optical Tube Diameter: | 180mm (7.12") |
| Optical Tube Weight: | 10 lbs (4.54 kg) |
| Dovetail: | CG-5 Dovetail bar |
| Solar Warning |
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| California Residents | View Proposition 65 Warning |
Software and Documentation
6" Schmidt-Cassegrain Optical Tube Assembly Dimensional Drawing