Angle Telescope Eyepiece
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Bushnell PowerView 20x50 Super High-Powered Surveillance Binoculars
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DescriptionBushnell PowerView binoculars offer the best of both worlds, combining contemporary styling and design with traditional Bushnell quality and durability. This particular PowerView binocular offers a 20x magnification--among the most powerful in its class--and a 50mm objective diameter. The multicoated optics, meanwhile, guarantee superior light transmission and brightness, helping you see just about any target, whether you're searching for birds or trying to get a better view of the football field. And users will love the patented InstaFocus focusing system, which holds your subject in sharp focus with a touch of the fingertip. Additional features include a porro prism system, a nonslip rubber armor housing that absorbs shock while providing a firm grip, a neck strap, and 9mm of eye relief. Specifications: Magnification: 20x Objective lens diameter: 50mm Size class: Standard Focus system: InstaFocus Prism system: Porro Prism glass: BK-7 Lens coating: Multi Field of view @ 1,000 yards: 170 feet Close focus distance: 45 feet Exit pupil: 2.5mm Eye relief: 9mm Eyecups: Fold down Waterproof/fogproof: No Adapts to tripod: Yes Weight: 30 ounces Warranty: Limited lifetime The Bushnell(r) Powerview(r) Series of binoculars offers you compact, streamlined designs for bright, crisp views of wherever you're exploring. Features
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Physics lens question!?
Mars subtends an angle of 8.0 rad multiplied by 10.5 to the naked eye. An astronomical telescope has an eyepiece with a focal length of 0,040 m. When Mars is using this telescope, covering an angle of 3.10 rad 03.10. Find the focal length of objective lens of the telescope. ___m
For telescopes of the expansion M = θ '/ θ = -f1/f2 θ is the angle where the telescope, θ is the angle of view, f1 is the lens focal length and is the focal length f2 of the eyepiece. Thus M = 3.10x10 ^ -5 = 38.75 -3/8.0x10 Therefore f1 = f2 = M * 0.040m * 38.75 = 1.55 m
US $7.45
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Bushnell PowerView 20x50 Super High-Powered Surveillance Binoculars
List Price: |
DescriptionBushnell PowerView binoculars offer the best of both worlds, combining contemporary styling and design with traditional Bushnell quality and durability. This particular PowerView binocular offers a 20x magnification--among the most powerful in its class--and a 50mm objective diameter. The multicoated optics, meanwhile, guarantee superior light transmission and brightness, helping you see just about any target, whether you're searching for birds or trying to get a better view of the football field. And users will love the patented InstaFocus focusing system, which holds your subject in sharp focus with a touch of the fingertip. Additional features include a porro prism system, a nonslip rubber armor housing that absorbs shock while providing a firm grip, a neck strap, and 9mm of eye relief. Specifications: Magnification: 20x Objective lens diameter: 50mm Size class: Standard Focus system: InstaFocus Prism system: Porro Prism glass: BK-7 Lens coating: Multi Field of view @ 1,000 yards: 170 feet Close focus distance: 45 feet Exit pupil: 2.5mm Eye relief: 9mm Eyecups: Fold down Waterproof/fogproof: No Adapts to tripod: Yes Weight: 30 ounces Warranty: Limited lifetime The Bushnell(r) Powerview(r) Series of binoculars offers you compact, streamlined designs for bright, crisp views of wherever you're exploring. Features
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Nikon 7216 Action 8x40mm Binoculars
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DescriptionA great bang-for-the-buck binocular, the 8x40 Action VII Binocular is the 'standard' entry in value-driven porro prism lineup, featuring a tremendous view that's relaxed and spacious. It is a great choice enjoying stadium sports, and also makes for a sensible birding or hunting selection. Its high-refraction prisms combined with the 8x magnification yield a wide 8.2 degree true field of view, and the aspherical eyepiece design makes for a wide apparent field as well. The Action VII has multicoated objectives, protective rubber armor, and conventional peel-down style rubber eyecups Features
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Celestron 93230 8 to 24mm 1.25 Zoom Eyepiece
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DescriptionThe Celestron 93230 8 to 24 millimeters 1.25 inch zoom eyepiece allows you to zoom instantly with your scope from 8x magnification to 24x magnification. Celestron 8-24mm 1.25" Zoom Eyepiece for 1 1/4-in Celestron Telescopes 93230 Features
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Orion SkyQuest XT10i IntelliScope Dobsonian Telescope
Sale Price: $749.99 |
DescriptionThis remarkable scope combines powerful 254mm-diameter reflector optics with point-and-view simplicity in one nicely portable package. And with included Computerized Object Locator, even the first-time stargazer can pinpoint the location of 14,000+ celestial wonders stored in the IntelliScope's databank. It's like having your own personal tour guide to the universe! The optical tube houses an 10" (254mm) parabolic mirror and rides on our state-of-the-art Dobsonian base, equipped with springless CorrecTension friction control for smooth movement and always-perfect tube balance. Features
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Celestron Diagonal, Erect Image
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DescriptionCelestron?s Erect Image Diagonals are an Amici prism design. This design allows you to look into the telescope at a 45 angle, at images that are oriented properly, meaning the image is upright and correct from left to right. Use of Celestron?s .96" to 1-1/4" 45 Erect Image Diagonal on a telescope equipped with .96" eyepieces means greater versatility. This diagonal will allow you to use 1-1/4" eyepieces, to obtain a larger field of view and better eye relief. A 901-1/4" Erect Image Diagonal is available for those who prefer that angle. A Star Diagonal lets you view objects that are at a 90 angle from the direction the telescope is pointing, thereby allowing comfortable viewing when the telescope is pointed at, or near, the zenith (i.e. directly overhead). The resulting image is right side up, but will be reversed from left to right. |
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TwinStar White 70mm iOptron Computerized GPS Refractor Telescope
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DescriptionThis GPS telescope does it all with just the push of a button. Simply turn the telescope on, choose the object you want to see on the handheld controller and the computerized mount does the rest. North Star alignment not necessary with GPS. This incredibly balanced telescope is ideal both for space viewing and daytime observing. With a large 70mm aperture this telescope has a third more light gathering power than most smaller scopes. The fully coated achromatic 70mm primary objective lens is maintenance free and ready to use right out of the box. The 700mm focal length, combined with 3 include eyepieces and a 2x barlow lens means you'll enjoy a range of magnifications from 35x to 350x. That makes this telescope ideal for just about any observing application. The iOptron SmartStar-G Alt-Azimuth Mount with GPS, a.k.a. The Cube, is probably the most functional and flexible unit on the market. Both axis motors are built into a small single unit. In addition, there are no "dead spots" -- so you can point your telescope anywhere above the horizon, whereas, other mounts block the telescope tube at certain points of rotation. This mount also comes standard with AC connection. The mount also accepts 8 AA cell batteries for use at home or in the field (Batteries sold separately). The revolutionary GoToNova computerized control system is the most technologically advanced automated tracking system available on the market today. With a database of 50,000 celestial objects, including all of the most famous galaxies, nebulae, star clusters, not to mention the planets, you'll be able to enjoy star gazing with the simple push of a button. The GoToNova Controller is much easier to use than other similar products. The hand controller is more intuitive with menu categories better organized. It also has a larger LCD screen with more lines of content compared with the competition. Using the easy-to-use hand controller, you can easily set up your telescope and select where you want to go. Features
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Bushnell Powerview 8x21 Compact Folding Roof Prism Binocular (Black)
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DescriptionThe Bushnell(r) Powerview(r) Series of binoculars offers you compact, streamlined designs for bright, crisp views of wherever you're exploring. Bushnell PowerView binoculars offer the best of both worlds, combining contemporary styling and design with traditional Bushnell quality and durability. This particular PowerView binocular offers an 8x magnification and a 21mm objective diameter. The fully coated optics, meanwhile, guarantee superior light transmission and brightness, helping you see just about any target, whether you're searching for birds or trying to get a better view of the stage. And users will love the easy-to-use center focusing system, which adjusts quickly to keep your subject in sharp view. Additional features include a nonslip rubber armor housing that absorbs shock while providing a firm grip, a neck strap and a carrying case for easy transport, and 9mm of eye relief. Specifications: Magnification: 8x Objective lens diameter: 21mm Size class: Compact Focus system: Center Prism system: Roof Prism glass: BK-7 Lens coating: Fully Field of view @ 1,000 yards: 378 feet Close focus distance: 21 feet Exit pupil: 2.6mm Eye relief: 9mm Eyecups: Fold down Waterproof/fogproof: No Adapts to tripod: No Weight: 7 ounces Warranty: Limited lifetime Tech Talk Objective Lens: The diameter of the objective or front lens. The larger the objective lens, the more light that enters the binocular, and the brighter the image. Field of View (F.O.V.): The side-to-side measurement of the circular viewing field or subject area. It is defined by the width in feet or meters of the area visible at 1000 yards or meters. A wide angle binocular features a wide field of view and is better for following action. Generally, the higher the magnification, the narrower the field of view. Roof Prism System: In roof prism binoculars the prisms overlap closely, allowing the objective lenses to line up directly with the eyepiece. The result is a slim, stream-lined shape in which the lenses and prisms are in a straight line. The Bushnell 8x21 PowerView FRP compact binoculars combine contemporary styling and design with traditional Bushnell quality and durability. They are easy to use and economical and feature general-purpose roof prisms. They offer 8x magnification and a field of view of 378 feet at 1,000 yards in a compact 7-ounce body. Their black rubber armoring ensures they can sustain active use. Bushnell's 8x21 PowerView FRP compact binoculars include a carrying case and a neck strap for convenience and comfort on the go. Features
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