There are state-of-the-art Starbright XLT multicoatings on the hand-figured 14" aperture SCT optics of this impressive optical tube, plus a Fastar-compatible secondary that lets you add an accessory lens to cut the focal ratio to an astonishing f/2.1 for CCD imaging.
This impressive 45 lb. 14" Celestron Schmidt Cassegrain aluminum optical tube has a state-of-the-art Starbright XLT multicoated Fastar-compatible optics and a light grasp that's an amazing 2581 times that of even the sharpest dark-adapted eye (36% greater than a 12" telescope and almost twice that of a 10" scope). With the effective light-gathering power of that many eyes, the Schmidt-Cassegrain optics of this optical tube can reveal to you faint deep space objects in amazing and intricate visual and photographic detail. It has a 3910mm focal length and a focal ratio of f/11. An optional focal reducer is available to bring the focal ratio down to f/6.9 for CCD and 35mm photography. Optical performance is guaranteed to be diffraction-limited.
The optics are Fastar compatible. This special optical system allows you to replace the scope's secondary mirror assembly with an auxiliary Fastar lens and a suitable CCD camera (an exchange that takes only minutes) for wide field CCD imaging at an incredibly fast f/2.1 focal ratio.
Advanced high transmission Starbright XLT optical multicoatings are standard equipment. This coatings package includes high reflectivity multilayer aluminum mirrors enhanced with titanium dioxide for high reflectivity, plus a unique combination of magnesium fluoride and hafnium dioxide antireflection coatings on both sides of the Schmidt corrector lens. The corrector lens itself is made of high transmission water white float glass instead of conventional soda lime glass (which has 3.5% lower transmission) used in other telescopes.
Starbright XLT multicoatings visibly increase the contrast on subtle lunar, planetary, and nebula details when compared with a scope with standard multicoatings. They also give you higher light transmission for brighter deep space images and shorter exposure times during CCD and 35mm photography. Across the total visual/photographic spectrum from 400nm to 750nm, independent laboratory tests show the new Starbright XLT coatings are 16% brighter overall than even the original industry-standard Starbright multicoatings.
The optics are hand-figured. Hand figuring the optical system is a complex optical procedure done on a commercial basis only by Celestron. Four separate optical tests are made on every set of optics, using a double-pass laser autocollimator - an Airy disc inspection, a test for spherical aberration by examining the diffraction images on both sides of focus, a Ronchi grating test, and a knife edge test. A skilled optician evaluates these tests. He then fabricates a precision pitch lap and delicately hand polishes the secondary mirror to compensate for any small residual zonal defects and smooth the optical figure. Done a few strokes at a time, and testing constantly to evaluate their effect, this final hand-figuring can take hours. But, when it is finished, the optical performance makes every tedious hour of hand-crafting well worth the effort.
The optical tube comes with a big 9 x 50mm straight-through achromatic finderscope and mounting bracket. The finder has a wide 5° field of view. It focuses by loosening the trim ring behind the objective lens cell, screwing the lens cell in or out to focus, and tightening the trim ring to lock in the correct focus. Also standard is a 2" mirror-type star diagonal, as is a 1.25" 40mm plossl eyepiece. This eyepiece provides a magnification of 98x. Its field of view is 0.51° across, as wide as the full Moon. Dust covers for the optics are also supplied.
The optical tube is equipped with a slide bar with a standard 75mm (3") wide dovetail for mounting the tube on a Celestron CGX-L Computerized German equatorial mount or a suitable mount that has a losmandy style saddle plate.
