Section 2 - Market TrendsIf we would like to show the recent history of market in a "distorted mirror", we could say that many amateur astronomers have left their mirrors alone and moved towards lenses for their better thermal properties. Then the same amateurs have gradually forced the manufacturers to design and build lenses with extremely fast focal ratios (for nice, easily transportable telescopes), so today they use APO lenses that do not have much better thermal properties than those old mirrors they left a few years ago. :-)))In the case of travel telescopes we believe the recent changes of refractor design principles and the movement towards faster focal ratios are all very reasonable, as a result, today's amateurs can have much better and smaller travel telescopes, and also today's average travel scope has more aperture and less false color than most "home" refractors a few decades ago. But travel scopes have (on today’s refractor aperture scale :-) smaller aperture, where the problems caused by the fast (and thick) optics are less dramatic compared to larger telescopes. So, we believe that a fast triplet APO lens in a travelling telescope is an excellent compromise. But in the case of scopes that are intended to be used primarily at home (and usually featuring more aperture), we believe the race for even shorter focal lengths is unnecessary, especially as the price of equatorial mounts has significantly dropped recently. Today, even manufacturers of the Far East often produce mounts with acceptable quality and enough performance to easily handle a refractor with bit longer focal length, and the performance we can gain with this is easily worth the extra length of the telescope. Also, most of today's telescopes (especially those used for astrophotography) are over-mounted, and on these large, strong and high quality mounts it is not a big difference if the focal length of the scope is longer by 4 - 8 inches. But it is a significant difference if the scope has less thermal problems and thus can produce planetary images of the highest quality. | |
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