Telescope Objective Lens
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Gregorian telescope Photo Mugs
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DescriptionThis small brass reflecting telescope uses a curved mirror rather than an objective lens to collect light and produce the observed image.. Features
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An explanation of the resolving power of telescopes
Enlargement of a telescope is easy to understand. The greater the power closer look we get images in the night sky (are larger). Resolution is another critical component of the telescopes and is very easy to understand if think of it as television sets. Older televisions have a number of lines of resolution and new high definition sets have many more lines resolution so you can get a sharper picture and detailed. The same applies to the telescopes, the higher the resolution the more lines of information we get so the better the image. And this resolution has nothing to do with enlargement. If you approach your TV does not get sharper image? No. Just becomes larger. The resolution remains the same.
Factors affecting resolution
The wavelength of light is observed is a factor in the resolution. The higher the wavelength of light waves of a telescope to see what information gets more and better the resolution. A second factor is the size of the telescope objective. The bigger the lens or mirror the wavelengths will meet. And more lengths wave means a better resolution.
Formula for solving
This relationship between the wavelength of light and the diameter of the telescope objective gives us, along with a constant, a formula for calculating the resolution in arc seconds. Divide the diameter of the objective the telescope for the wavelength of light is observed, then multiply this by 252 000 (which is our constant). This gives the resolution in arc seconds. (Resolution = 252 000 X (wavelength) / (diameter)). You can see that the larger the telescope the smaller the resolution is in seconds of arc. And the lower resolution in arcseconds, the better. It's like little lines on your HDTV. Small lines means more lines per inch or centimeters and a drawer, the sharpest image.
Other factors in the resolution of the Telescope
The conditions weather is an important factor in the resolution. A turbulent atmosphere, thick, distorted or unstable wavelengths entering the telescope and distort the quality of light and information. This will reduce the resolving power.
The quality of the telescope is another factor. Areas of high quality with good optics properly gather good information and give you a good resolution. Poor quality of optical images are distorted and give a lower resolution.
Resolution, while less known that the increase is much more important. It is the factor that determines the quality and sharpness of what is seen through the telescope and is the reason why big telescopes are better than smaller ones.
About the Author
You can read a more comprehensive explanation of telescope resolution, with drawings, on the authors website : TelescopeNerd.com
Why is the objective of a telescope to be great?
Two reasons: 1) The larger the area of the lens, which will gather more light. Space is a function of the square of the aperture, so a goal of two inches in diameter accepted four times in the light of an objective of an inch in diameter. Its image is four times brighter. 2) The larger the lens opening, the higher the resolution, ie the lower the detail that can be resolved. A two-inch lens detail can solve half the size of which was resolved by a lens of an inch.
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 New iOptron SmartStar GPS GoTo Telescope with 70mm Primary Objective Lens  US $424.99
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 Star 60050 Refractor Telescope w 50mm Objective Lens US $65.95
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 bausch lomb telescope OBJECTIVE LENS US $39.99
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 Star Refractor Telescope w 50mm Objective Lens NIB NEW US $69.99
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 Star 60050 Refractor Telescope with 50mm Objective Lens US $43.82
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 NEW Star 60050 Refractor Telescope 50mm Objective Lens US $84.50
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 Science Astronomical 25 50 Power 40MM Telescope Tripod Mount Objective Lens US $16.00
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Gregorian telescope Photo Mugs
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DescriptionThis small brass reflecting telescope uses a curved mirror rather than an objective lens to collect light and produce the observed image.. Features
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Gregorian telescope with case Photo Mugs
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DescriptionThis small brass telescope is a reflecting telescope that uses a curved mirror rather than an objective lens to collect light and produce the observed image.. Features
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Lookout telescope Photo Mugs
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DescriptionThis is a hand-held achromatic telescope for use on board ship. It has a single draw tube, an extending shade for the objective lens to reduce glare when in use and a sliding eyepiece cover. The barrel is covered in leather, while all the other fittings are brass.. Features
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Night Owl Pro Nexgen Night Vision Binocular (5x)
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DescriptionThe highest magnification binocular available, Night Owl Optics' 5-power binocular is an advanced, highly acclaimed generation-1 binocular. The aesthetics, ergonomics, and performance of this instrument are high-quality and recommended by the manufacturer for those who demand the highest performance that generation-1 technology can offer. A central focusing wheel allows for quick and easy focusing of both objective lenses simultaneously. And Night Owl's proprietary interocular hinge guarantees you that both optical channels are always centered precisely over each eye. Features: 5x magnification Adjustable focus with central focusing mechanism Two high-quality generation-1 image intensifier tubes Adjustable interocular distance centers the dual optical channels precisely over each eye Built-in columnated infrared illuminator for use in complete darkness or to improve target recognition in any environment Objective and ocular lenses constructed of high-quality all-glass optics Soft-touch rubberized finish Impact-resistant molded thermoplastic lens housings Padded neck strap Specifications: Magnification: 5x Objective Optic Design: manual focus Lens Diameter: 50 mm Resolution: 35 lp/mm on center Spectral Sensitivity: 400 nm to 900 nm Diopter adjustment: +4 to -4 Interocular distance: adjustable from 57 mm to 73 mm Minimum Focal Distance: 3.6 feet (1.1m) Angular Field of View: 12.5 degrees Field of View at 200 ft. distance: 44 feet wide (61m / 13.4m) Dimensions: 8.00 by 5.85 by 2.60 inches (L x W x H) Weight, without batteries: 38 ounces Power Supply: requires (1) 3-volt Type-123 lithium battery (not included) Battery Life: 40 to 80 hours, depending on infrared usage. Infrared Illuminator, built-in Night Owl NOB5X 5.0x NexGen Night Vision Binoculars with 50mm Lens 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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Tasco Essentials 8x21 Binocular (Black)
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DescriptionThese ultra-light binoculars offer outstanding compact performance with rugged rubber armor for hiking backpacking or bicycle touring. Features
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Bushnell Powerview 12x25 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 a 12x magnification and a 25mm 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 Insta-Focus system, which adjusts quickly to keep your mobile 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: 12x Objective lens diameter: 25mm Size class: Compact Focus system: Center Prism system: Roof Prism glass: BK-7 Lens coating: Fully Field of view @ 1,000 yards: 240 feet Close focus distance: 25 feet Exit pupil: 2.1mm Eye relief: 9mm Eyecups: Fold down Waterproof/fogproof: No Adapts to tripod: No Weight: 11.3 ounces Warranty: Limited lifetime Features
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Celestron 44102 400x Power Laboratory Biological Microscope
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DescriptionThe Celestron(r) 400x Laboratory Biological Microscope comes with many scientific essentials such as a diaphragm and a condenser. Its efficient charm comes in its power and precision, with 3 different objective lenses and a monocular, adjustable head that rotates from 0 to 60 degrees for comfortable viewing. Features
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Orion Observer 70mm Equatorial Refractor Telescope
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DescriptionThis tried-and-true refractor goes the extra distance in introducing the novice to the wonders of the night sky. The Observer 70 features a 70mm fully anti-reflection coated achromatic objective lens, which provides 36% more light-gathering ability than a 60mm. Its 700mm focal length (f/10) will show you the stark beauty of the lunar surface, Saturn's rings, Jupiter's atmospheric belts, or the billowy clouds of the Orion Nebula. The included EQ-1 equatorial mount comes equipped with dual slow-motion controls for manual star tracking and adjustable aluminum tripod. Includes an EZ Finder II finder scope to help you zero in on your celestial targets, two eyepieces - 25mm (1.25") and 10mm (1.25") - and 90-deg star diagonal. One year limited warranty. Orion’s Observer 70 EQ combines the solid optical performance of a classic achromatic refractor with a German style equatorial mount. The Observer 70 features very good optics and 36 percent more light gathering power than 60mm beginner scopes. The complete accessory package includes high and low power eyepieces, a 90 degree star diagonal, a red-dot finder, illustrated instructions, and Orionâs Starry Night Special Edition astronomy software. The Observer 70 EQ features very good optical performance. Achromatic refractors have a two piece objective lens, the second lens element compensates for “chromatic aberration”, the false color or blue fringes seen in low cost telescopes. In daylight tests I see very little blue fringing with the standard equipment 10mm eyepiece (70X magnification), and none at all with the 25mm eyepiece (28X). Stars and planets show up very nicely with the Observer 70. The quadruple star in the Orion Nebula known as the Trapezium is cleanly split into four components with the 10mm eyepiece (70X magnification). When I combine the 10mm eyepiece with a 2X Barlow lens for 140X magnification, I’m treated to lovely views of Saturn’s rings and the little orange disk of Mars. My view of the Moon is delightfully crisp and clear; the 25mm eyepiece nicely frames the Lunar disk, and using the 10mm eyepiece I can easily see mountain peaks and terraced walls inside the crater Copernicus. The Observer 70 EQ also features an aluminum tripod and an EQ-1 equatorial mount. The equatorial mount is a little more complicated to balance and align than the Observer 70 AZ , but the reward is better slow motion control and tracking at magnifications over 100X. Simply point the equatorial axis at Polaris, the North Star, and the telescope tracks celestial objects by turning one slow motion knob. This makes it much easier to use a high power eyepiece while viewing the Moon and Planets. The “EZ Finder II” works by shining a red LED on a small window; just look through the window and line up the red spot with your target. This works OK for bright objects like the Moon and planets but not so well for finding galaxies and deep space objects. Orion’s Observer 70 EQ is simply a very good entry level telescope for a student or family. The good quality 70mm optics produce an image that is significantly sharper and brighter than 60mm beginner scopes, and the package includes a solid mount, two good eyepieces, and fully illustrated instructions. --Jeff Phillips Pros: Reliable refractor design Good views of the Moon and planets Complete accessory package Starry Night software included Cons: Finder only works for bright objects Features
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Orion Observer 70mm Altazimuth Refractor Telescope
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DescriptionOur Observer 70 is the perfect telescope for that budding astronomer in your family. This scope excels in both quality and performance. Its 70mm multi-coated achromatic objective lens - focal length 700mm focal length (f/10) - gathers 36% more light than a 60mm. And it's made of glass, not plastic, as you'd find in many department store models. The optical tube is supported on a sturdy aluminum tripod with accessory tray. This altazimuth model can also be used for terrestrial viewing. Standard accessories include a 10mm (70x) Explorer II eyepiece, a 25mm (28x) Explorer II eyepiece, 90-deg mirror star diagonal, and an EZ Finder II finder scope. One-year limited warranty. Features
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