|
Celestron - C-11A 11 inch Optical Tube Assembly, aluminum tube and StarBright XLT Coatings
|
$ 2090.00
| |
| 91036XLT
 |
|
11" Schmidt-Cassegrain, 2800 mm focal length, (f/10), Starbright coatings, 9 x 50 finderscope, 40mm eyepiece (70x) 1 1/4", star
diagonal 1-1/4", visual back 1-1/4", dovetail slide bar, Aluminum Optical Tube.
Celestron has brought its renowned StarBright technology to an even higher level of light transmission with the introduction of
our new optional StarBright XLT High Performance Optical Coating System.
StarBright XLT Optical System Design - You'll See The Light.
One of the most important factors in the evaluation of a Schmidt-Cassegrain telescope's optical system performance is its
transmission - the percentage of incoming light that reaches the focal plane. The design of the XLT System accomplishes two
crucial objectives: Develop a coating system that is optimized for visual use and for CCD/Photographic imaging.
The StarBright XLT System - What Makes It Different Makes It Better
There are three major components that make up our StarBright XLT high transmission optical system design:
1. Unique enhanced multi-layer mirror coatings
Our mirror coatings are made from precise layers of Aluminum (Al), SiO2 (quartz), TiO2 (Titanium Dioxide), and Si02. Reflectivity
is fairly flat across the spectrum, optimizing it for both CCD imaging and visual use. Click here to see a plot of the
reflectivity of XLT's Mirror Coatings.
2. Multi-layer anti-reflective coatings
Made from precise layers of MgF2 (Magnesium Fluoride), and HfO2 (Hafnium Dioxide) A rare element costing nearly $2000 per
kilogram, Hafnium gives us a wider band pass than Titanium, used in competing coatings. Click here to see a plot of XLT's
corrector transmission.
3. High Transmission Water White glass
Celestron Schmidt-Cassegrain optical systems with optional StarBright XLT coatings use Water White glass instead of Soda Lime
glass for the corrector lens. Water White glass transmits about 90.5% without anti-reflective coatings. That is 3.5% better
transmission than uncoated Soda Lime glass. When Water White glass is used in conjunction with StarBright XLT's anti-reflective
coatings, the average transmission reaches 97.4% - an 8% improvement! Click here to see a plot of water white glass versus soda
lime.*
These three components of our StarBright XLT coatings result in one of the finest coatings available. The peak transmission for
the systems is 89% at 520 nm. The overall system transmission is 83.5% averaged over the spectrum from 400 to 750 nm.
|
