Celestron C9 1/4 A (XLT) Schmidt-Cassegrain Optical Tube - 91027-XLT

This 9.25” aperture optical tube gathers 33% more light than an 8” scope, providing brighter images of faint deep space objects. Its light-gathering ability is over 1125 times that of even the sharpest dark-adapted eye. The optical design uses a longer focal length primary mirror and lower magnification secondary mirror than a conventional SCT. This yields a flatter field of view at the focal plane. It also reduces optical aberrations during photography and when using wide field long focal length 2” eyepieces. An optimized baffle system further improves astrophotography by minimizing vignetting at the corners of a 35mm negative or large format CCD. Advanced Starbright XLT 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.