Celestron provides their high grade Schmidt Cassegrain optics as a tube assembly only to use with your favourite mount. The popular C11 features premium StarBright XLT coatings, a 2800mm focal length (f/10), a 9×50 finderscope, and a dovetail rail compatible with CGE (wide 3″) dovetails.
Celestron C11-A XLT Optical Tube Assembly
Celestron provides their Schmidt Cassegrain optics as a tube assembly only to use with your favourite mount.
- 11″ Schmidt-Cassegrain Optical Tube Assembly
- Aluminum Optical Tube
- Celestron’s premium StarBright XLT coatings
- 2800 mm focal length (f/10)
- 40 mm eyepiece included (70x)
- Visual back allows for use with 1.25″ accessories
- 9×50 finderscope to help accurately find objects
- Star diagonal provides more comfortable viewing position when observing objects that are high in the sky
- Includes dovetail rail compatible with CGE (wide 3″) dovetails
Celestron C11-A XLT OTA Specifications
Optical Design |
Schmidt-Cassegrain |
Aperture (mm) |
279.4 mm (11 in) |
Focal Length |
2800 mm (110 in) |
Focal Ratio |
10 |
Focal Length of Eyepiece |
40 mm |
Magnification of Eyepiece |
70 x |
Finderscope |
9×50 |
Star Diagonal |
1.25″ |
Optical Tube |
Aluminum |
Highest Useful Magnification |
660 x |
Lowest Useful Magnification |
40 x |
Limiting Stellar Magnitude |
14.7 |
Resolution (Rayleigh) |
0.5 arc seconds |
Resolution (Dawes) |
0.42 arc seconds |
Light Gathering Power (Compared to human eye) |
1593 x |
Secondary Mirror Obstruction |
95 mm |
Secondary Mirror Obstruction by Diameter |
34% |
Secondary Mirror Obstruction by Area |
12% |
Optical Coatings |
StarBright / XLT |
Optical Tube Length |
610 mm |
Optical Tube Weight |
12 kg |
Dovetail Compatibility |
CGE Mount |