telescope diagonal
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TeleVue 2-Inch 90 Degree Enhanced Aluminum Diagonal - TVU048-1
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DescriptionTele Vue 90 Degree Diagonal - 2 InchThe 2" Enhanced Aluminum mirror coating provides a 96% reflective surface across all but the extreme ends of the visual spectrum. The enhanced coating provides extra reflectance versus competing standard aluminum coatings. The final coating stage applies a tough overcoat to protect the aluminum. The diagonal body has the same features as the Everbrite. The Enhanced Aluminum 1 1/4" diagonal features a 96% reflective mirror coating. All diagonals feature brass clamp rings and filter threads. The Enhanced Aluminum diagonals are good budget alternatives especially where a prism diagonal might otherwise be considered. |
How to clean your new acrylic awnings
The new awnings you purchased for your home are most likely made from a synthetic solution dyed acrylic fabric. The most recognizable brand name of this fabric is Sunbrella, other brand names are Dickson Constant, Recacril, Sattler, and Tempotest. All these fabrics have been treated during the manufacturing process with water repellants and mildew inhibitors. Cleaning the awnings will affect this treatment so it is a good idea to retreat the fabric once cleaning has been completed and fabric is dry. The following is a quick guide to effectively cleaning your awnings and treating them in order to ensure a long life for your awnings while looking great.
Step 1: Determine the fabric your awnings have been manufactured from. If they are any material other than solution dyed acrylic then do not use these instructions. Some of the other materials used in residential awnings include cotton, vinyl, and coated polyesters. If you have trouble determing the fabric your awnings are made from then call the manufacturer/installer and inquire. Most companies keep these records readily available.
Step 2: Be safe!! If you are going to clean the awnings while they are still on their frames make sure you use the proper ladders in order to reach the awnings. If you clean the awnings after you have taken them down for the season then make sure you clean them on a smooth clean surface.
Step 3: To clean the awning properly you will need a soft bristle brush. Preferably one with a telescoping handle. Mix a solution of Dawn dishwashing detergent ( or ivory snow ) and water to start with, this solution should take care of most of the common dirt found on awnings. Rinse the awning first to get the fabric wet and then brush the solution onto the awning, brush up and down and diagonally. Rinse well to ensure all detergent has been rinsed away.
For stubborn stains that remain on the awning following a basic cleaning you will need to use a different method and cleaning agents. The following are some of the most common stains found on awnings and the method used to get rid of these stains.
Mildew: Use 1 cup of bleach and 2 ounces of Dawn dishwashing liquid and one gallon of warm water. Let the solution soak into the fabric for 30 minutes and then follow the instructions above. Be careful to wear gloves and eye protection and be aware of whatever else is in the vicinity of your awning that could be affected by the bleach solution. With this method it is best to clean the awning away from the house, shrubbery, flowers , etc.
Tree sap: Use turpentine directly on the sap and then the solution of Dawn dishwashing liquid/water.
Bird droppings: Dry bird droppings can sometimes be lightly scraped away. Try this first if you can reach the offending birds parting gift. Once you have done this then attack the rest of it with Goo Gone Grease Cutter, Greased lightning or Clean Rite Purple Power.
Grease/Oil: Use a volatile solvent (acetone). Then use soap and water. Again as with any powerful cleaner be aware of what is around the awning. Also wear eye protection and gloves. As with any strong chemical follow the manufacturers recommendations regarding the safe handling of their product.
Step 4: After the awning has dried completely. Retreat your fabric with 303 Fabric Guard.
If you follow these steps you will prolong the life of your awnings while keeping them looking great.
About the Author
To learn more about how awnings can beautify your home and make it more energy efficent visit www.prosinshade.com
How does a newtonian reflecting telescope work?
My new telescope has piqued my curiosity--More specifically, why is it that when looking into the eyepiece we don't see the cross shaped mount for the diagonal mirror (or the mirror itself?) in the image? I can't get my head around the problem and it's been so long since I did optic physics that I've pretty much forgot how it all worked....
The central obstruction is before the light is focussed by the telescope. Consider a star anywhere in the field of view. What point of the mirror does the light from that star hit? It should be obvious that if you ignore the central obstruction the light from that one star shines on the entire surface of the mirror, not just one point.
The whole job of the telescope is to sort out these rays of light so that there is a 1:1 correlation between the _direction_ of incoming light rays and the _position_ of those light rays on the focal plane. So the light of stars in the middle of the field of view hit the edges of the mirror and are directed to the centre of the image further along the optical path.
The "hole" in the image is all over the image in the form of lost light making a dimmer image, not concentrated in one position of the resulting image.
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 Celestron AstroMaster 130EQ Dual Purpose Telescope 2 Eyepieces Star Diagonal  US $224.99
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 125 inch partial telescope eyepiece mirror diagonal US $4.95
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TeleVue 2-Inch 90 Degree Enhanced Aluminum Diagonal - TVU048-1
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DescriptionTele Vue 90 Degree Diagonal - 2 InchThe 2" Enhanced Aluminum mirror coating provides a 96% reflective surface across all but the extreme ends of the visual spectrum. The enhanced coating provides extra reflectance versus competing standard aluminum coatings. The final coating stage applies a tough overcoat to protect the aluminum. The diagonal body has the same features as the Everbrite. The Enhanced Aluminum 1 1/4" diagonal features a 96% reflective mirror coating. All diagonals feature brass clamp rings and filter threads. The Enhanced Aluminum diagonals are good budget alternatives especially where a prism diagonal might otherwise be considered. |
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TeleVue 2-Inch 90 Degree Enhanced Aluminum Diagonal - TVU048
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DescriptionTele Vue 90 Degree Diagonal - 2 InchThe 2" Enhanced Aluminum mirror coating provides a 96% reflective surface across all but the extreme ends of the visual spectrum. The enhanced coating provides extra reflectance versus competing standard aluminum coatings. The final coating stage applies a tough overcoat to protect the aluminum. The diagonal body has the same features as the Everbrite. The Enhanced Aluminum 1 1/4" diagonal features a 96% reflective mirror coating. All diagonals feature brass clamp rings and filter threads. The Enhanced Aluminum diagonals are good budget alternatives especially where a prism diagonal might otherwise be considered. |
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Tele Vue 2" Everbrite Mirror Star (90°) Diagonal with Brass Clamp Ring -Black Satin Finish
Sale Price: $284.95 |
DescriptionWhiter and brighter images. Simply put, that is the benefit the Everbrite mirror coating. This exotic, dielectric, nonmetallic coating is 99% reflective across the full visual spectrum, resulting in the "whitest," most natural image available. The coating is painstakingly applied to Pyrex with a surface accuracy of a 1/10 wave flatness. The Everbrite is offered in both 1¼" and 2" models. The diagonal bodies of each are machined from solid blocks of aluminum. In this way we can insure permanent alignment. The one piece body construction also assures heavy accessories can't force the diagonal body to "unscrew" from the barrel as with other brands. Both the 1¼" and 2" models feature brass clamp rings, anti-reflection threads and 1¼" and 48mm filter threads respectively. Features
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Televue 90° 1 1/4'' DPC-1250 Everbrite
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DescriptionTelevue 90° 1 1/4'' DPC-1250 Everbrite Diagonal |
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Televue SCT 90° 2" Everbrite Diagonal DPS-2004
Sale Price: $306.99 |
DescriptionTelevue SCT 90° 2" Everbrite Diagonal DPS-2004 |
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Celestron 21061 AstroMaster 70 AZ Refractor Telescope
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DescriptionCelestron AstroMaster 70AZ 45 - 90X Refractor Telescope. Affordable, powerful, lightweight... the perfect choice for amateur astronomers and backyard stargazers! Proving once again that you don't need NASA's budget to see the stars. If you're aiming to get started in astronomy, the AstroMaster 70AZ's blend of quality optics, entry-level usability and affordable price is tough to beat. It's lightweight, easy to haul to the darker skies found outside city limits, and requires no tools to set up. For celestial and "earthbound" observation on a dime, the Celestron AstroMaster outshines the rest! Specifications: Pan-handle altazimuth style mount controls easily for smooth pointing; perfect for terrestrial and celestial viewing; 70 mm aperture size; Includes 20 mm eyepiece for 45X magnification, 10 mm eyepiece for 90X; Refractor optical design; Fully-coated glass optics with high-transmission coatings for enhanced brightness and clarity; Built-in StarPointer red laser for easy targeting; Comes with The Sky X Planetarium software, featuring a 10,000 object database to get you started; Focal length: 900 mm; Focal ratio: 12.86; Limiting stellar magnitude: 11.7; Light-gathering power: 165X; Angular F.O.V.: 1.1 degrees; Linear F.O.V.: 58'; Optical tube length: 36"; 1.25" erect image diagonal; Weighs 18 lbs. Includes aluminum tripod with 1.25" steel tube legs. Order yours today! Celestron AstroMaster 70AZ 45-90X Refractor Telescope Features
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Celestron 52268 C90 Mak Spotting scope (Black)
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DescriptionCelestron’s 52268 90mm Maksutov Spotting Scope delivers excellent high power optics in a compact, affordable package. The 52268 package includes a backpack style soft carrying case, an 8x21 erect image finder scope, a 1.25 inch size correct image 45* prism diagonal, and a fully coated 32mm plossl eyepiece for a magnification of 39X. The Maksutov-Cassegrain design of the C90 uses a combination of mirrors and lenses; this “folded” optical system has a focal length of 1250mm in a body only twelve inches long. The Maksutov design delivers high power views without a trace of the chromatic aberration, also called blue fringing, that can distort high power views in competing refractor style spotting scopes. At 40X magnification where some low cost spotting scopes start to seem fuzzy, the C90 is just getting started. The C90 uses the same 1.25 inch eyepieces used in astronomical telescopes. The standard equipment 32mm plossl eyepiece yields a magnification of 39X, but many other eyepieces can be used to vary the magnification. The Celestron model 52268 seems very well built, with excellent multi-coatings visible on the front lens. The real beauty of this 90mm Maksutov spotting scope, however, is in the view it offers. When I use an optional 12.5mm eyepiece to look at Jupiter at 100X I can clearly see Jupiter’s major cloud bands as well as its four moons. When I look at the Moon and stars I can easily push the magnification to 200X with an optional 6mm eyepiece. When I look at birds in the backyard, I’m treated to delightful views full of vibrant color and crisp detail. With a close focus distance of only 15 feet, the detail and texture I see is simply amazing. High magnification viewing requires a solid tripod, of course. Celestron’s Heavy Duty Altazimuth Tripod comes with slow motion controls to allow the scope to be pointed precisely, and I can clamp the dovetail base on my CG5 mount for astronomical use. The other drawback to high magnification viewing is a narrow field of view; high magnification makes it hard to follow moving targets like birds in flight. Overall the Celestron C90 Maksutov Spotting Scope does a fine job as a companion to good pair of binoculars. The C90 also doubles as a portable astronomy scope; it won’t show the flag on the Moon but it will show thousands of craters on the Moon as well as showing the moons of Jupiter and the rings of Saturn. --Jeff Phillips Pros: Compact and portable Excellent high power optics Upgradeable with 1.25” eyepieces Adaptable for astronomy and photography Cons: Not waterproof The Maksutov optical design is recognized for being a portable design that is easy to use and has a variety of applications, making it an excellent choice for both terrestrial and astronomical usage. This C90 Mak has excellent optics with razor sharp images over a wide field, along with built-in T-adapter threads for adapting SLR cameras. It comes with a 32mm eyepiece, 45° erect image diagonal, and 8x21 erect image finderscope. Features
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Celestron NexStar 6 SE Telescope
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DescriptionThe Celestron NexStar 6SE Telescope is a state-of-the-art design that allows you to view incredibly detailed celestial bodies. The patented single-fork arm enables smooth operating within the optical tube. With the NexStar 6SE Celestron Telescope, the quality is undeniable and the viewing is spectacular as the Go To buttons capture the object of your choice. With the Celestron NexStar 6SE Telescope, you get serious performance and easy portability in this high-quality altazimuth computerized telescope.Features:6" Schmidt-Cassegrain telescope with 150mm aperture44% more light gathering power than 5" models1500mm focal lengthFocal ratio: 10Ultra portable – weighs 30 lb including the tripodCombines the classic heritage of the original orange tube telescopes with the latest state-of-the-art featuresStarBright XLT high transmission coatings come standardCelestron's unique patented single fork arm with integral hand control design provides a rigid and smooth operating structure for the optical tubeStar diagonal provides more comfortable viewing position when observing objects that are high in the skyProven NexStar computer control technologyIncludes:Quick release fork arm mount, optical tube and accessory tray for no-tool setupStarPointer finderscope to help with alignment and accurately locating objectsSturdy computerized altazimuth mountInternal battery compartment to prevent cord wrap during useUltra sturdy steel tripod with accessory tray40,000 object database with 200 user-definable objects and expanded information on over 200 objectsSkyAlign allows you to align on any three bright celestial objects, making for a fast and easy alignment processFlash upgradeable hand control software and motor control units for downloading product updates over the InternetAutoguider port for long exposure astrophotographyDC Servo motors with encoders on both axesCustom database lists of all the most famous deep-sky objects by name and catalog number; the most beautiful do Features
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Orion Observer 70mm Equatorial Refractor Telescope
Sale Price: $169.99 |
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
Sale Price: $139.99 |
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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