![]() If the number has a plus (+), you are farsighted.Ĭylinder (CYL): This indicates the lens power for astigmatism.If the number has a minus sign (–), you are nearsighted.Sphere (SPH): This indicates the lens power, prescribed to correct nearsightedness or farsightedness. OS: Stands for “oculus sinister”, Latin for your left eye. Operate in the dark.OD: Stands for “oculus dextrus”, Latin for your right eye. A zoom may soon join the others.Ĭaption: Left: The finder's zoom lever is easy to reach and * Contributing Editor JERRY OLTION festoons his telescopes withįinders of all description. and I use thisįor more information, contact Hunter at. Scopes, the finder I use most is the best one I have. Hunter's final assessment is this: "Like my Light-polluted skies, and it would probably be equally useful in dark The zoom finder nicely solves the problem of star-hopping in Other zoom lenses might work as well,īut make sure they come to focus far enough away from the rear element These zoom lenses are available on eBay fairly frequently and canīe found with a little patience. But Iįind the images good enough, and 'good enough' seems okay for Now he says the most serious downside is that "this opticsĬombination provides, to be kind, not the sharpest star images. Reports, "The long hand lever of the lens makes adjustment veryĮasy, so I just zoom in and out, tweaking the scope position until the Zoomed, but an object in the center of the field will stay put. Then one night while zooming in on a target, Hunter had anĮpiphany: The zoom could function like cross-hairs.Īn object that's not centered will drift to the side when The two finders let him zero in on just about any target visible in his So he augmented his zoomįinder with a second, conventional 5 optical finder. Indicate the center of his finder's field. Plane inside the Amici prism, he couldn't add cross-hairs to Hunter soon realized the biggest hiccup in his design: With the focal Wider than the 1 field of a typical low-power eyepiece, and Even at full zoom, its 12.5 field is still a lot Includes the front of the telescope, making it difficult to judge where At its widest, the finder's field of view Lever for zooming, so Hunter can shift back and forth easily without Designed for television cameras, the lens has a smooth-acting Zooming to the narrowest field of view, 12.5,Īdds about 3 magnitudes of gain, bringing out more stars as the field The result is a finder that zooms outward to give him a 50įield of view, which allows easy orientation even with only a few So their focal point reached the same plane. Zoom lens lies inside the prism, so he had to mount the eyepiece lenses HeĬouldn't use the entire eyepiece because the focal point of the ![]() Shop and mated a Sony 20-80 mm f/2.5 TV zoom lens to an inexpensiveĪmici roof prism and the lenses from a 20-mm Plossl eyepiece. "zoom finder" rattling around in his head, he went into his He began asking himself, "So what provides both wide-angleĪt about naked-eye field of view as well as some magnification when ![]() Reduce the number of useful field stars and put him right back where he Trouble is, that would lead to a narrower field of view, which would Hunter needed an optical finder that would offer some gain. More and, interestingly, the sense of slightly better star visibility,īut even so I just couldn't see enough stars on many nights." Split-pupil finder solved that problem, giving me a 50 field or Of any glass and is very wide angle, but my old bones don't likeĬrouching to look straight through finders. He reports, "Telrads and other reflex finders provide wideįields of view, but in my poor skies it's often difficult to seeĮnough stars, and looking through any glass further limits visibility. For the last several years he has experimented withĭifferent types of finders, but he found little that worked well for Practice that offers limited success when the magnitude-4 sky reveals He also enjoys manually aiming his telescope, a HUNTER DAVIDSON LIVES NEAR a large city, which subjects him to APA style: Hunter's Zoom Finder: This innovative design solves several problems at once.Hunter's Zoom Finder: This innovative design solves several problems at once." Retrieved from ![]() This copyrighted material is duplicated by arrangement with Gale and may not be redistributed in any form without written permission from Sky & Telescope Media, LLC. MLA style: "Hunter's Zoom Finder: This innovative design solves several problems at once." The Free Library. ![]()
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