![]() This significant difference in total system accuracy is one reason why a 7" Questar can routinely outresolve a 14" Schmidt-Cassegrain (or virtually any other larger aperture catadioptric or reflector scope) on globular clusters, binary stars, and lunar and planetary details - with the Questar invariably exceeding Dawes' limit for the best resolution available from an optical system of its aperture.Ī second reason is the turbulent Earth atmosphere all telescopes must look through. In either case, it's a far cry from the 1/8th wave total system accuracy entering the eyepiece of a Questar. However, they do not specify whether that is for individual components or the system as a whole. Most commercial telescopes claim to be "diffraction-limited" (which is generally assumed to mean 1/4th wave accuracy). That's twice the accuracy needed to meet Lord Rayleigh's Criterion, which specifies the level of optical excellence required to yield visual performance that is indistinguishable from perfect optics. Simply this: a fanatical devotion to hand-crafted accuracy.Įach optical element in a Questar typically tests out at a truly outstanding 1/50th wave accuracy (shaped to within four ten-millionths of an inch of perfection!) This produces guaranteed total system performance at the Cassegrain focus of 1/8th wave or better. What is it about a Questar that lets it outperform larger scopes on a day in/day out basis? The Crêpe Ring and Encke's Division in the rings of Saturn are routine with a Seven Classic in good seeing, as are myriad whorls and festoons in Jupiter's belts and hundreds of sub-kilometer craters on the lunar surface. While the 14" scope was brighter on the fainter objects, the superior contrast and resolution of the Questar Seven was easily visible. I have compared my own Questar Seven to a 14" Schmidt-Cassegrain on deep space objects such as the Sombrero galaxy, the Saturn Nebula, and Omega Centauri. Observe through a Questar Seven Classic Titanium optical tube with broadband optical coatings, and you'll see detail and clarity in the skies that you have never seen through a lesser scope, or even through many larger scopes. Astro-Tech AT60ED and AT72EDII Black Friday Sale.Explore Scientific Nebraska Star Party Sale. ![]()
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