Binoculars, Riflescopes, Spotting Scopes and other Optical Instruments and Accessories
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from these Manufacturers: top of page Recommended Books Using Binoculars for Astronomy Binocular FAQ What does "Catoptrics" mean in our title? top of page Why own binoculars? For a host of reasons. Here are a few: • Binoculars are great for watching sports. A Zhumell Zoom binocular can put you right in the action. • Binoculars are essential for birding. A pair of 10X Zeiss 10x42 FL-T binoculars can get you so close you can almost count the feathers. • Binoculars are great for hunting. Nikon Monarch binoculars will allow you to separate branches from antlers and give you a clear shot at a trophy. • Binoculars also are great for mariners. Scope out snags with Bushnell Marine binoculars. Binouculars for Bird-Watching The most popular binocular sizes for bird watching are 8x40 and 8x42. Binoculars with these specs are compact enough to carry with you all day while large enough to gather plenty of light. Other features to look for in birding binoculars are a close focus for near observation of birds and insects, a wide field of view, enabling you to track quick-flying birds and to see more individuals at a time when counting or observing large flocks or groups, such as kettles of hawks, and good depth of field so you don't need to keep adjusting the focus to keep a small bird in focus, and don't need to turn the focus adjustment too much to go from near to far. top of page Binoculars for Hunting As with the marine binocular, the hunter’s model should also be waterproof as well as rugged. Higher power is recommended because distance is often a key in hunting and you need to be able to see your target clearly. 8x42 and 10x42 are common choices, with some sort of more rugged housing to take potential abuse in the field. Binoculars for Marine Use For boating or any marine use, waterproofing is critical. The housing should be solidly built enough that it can take some punishment when it gets really rough. A power of 7 with a 50mm objective lens is most common for a marine binocular. This allows for a large field-of-view and an ample objective to collect a lot of light. Another feature of many marine type binoculars is a built in compass, perfect for navigation. Zoom Binoculars For ultimate utility, zoom binoculars are what you want. Zoom binoculars offer users a wide field of view and bright image at low powers and zoom in and view distant details quickly and easily. The key to the zoom type binoculars is the ability to change the power. In a 9-27x50, you can focus in a 9x50 and zoom it all the way up to 27x50 with the flip of a lever. This is great facility to have when you want to be just a little close to the subject. Using Binoculars for Astronomy Not interested in the complexities of a telescope? A good pair of binoculars
can bring the heavens closer in a much easier to use package.
Choosing a binocular for Astronomy When choosing a binocular for astronomy you first need to understand how binoculars work. Similar to telescopes, a binocular needs to gather light. The same critical feature for telescopes is the same in binoculars - you need a large enough objective lens to gather light. top of page Binoculars are measured with two key features - its magnification and its objective lens. For example, a binocular may be listed as 10x50. The first number 10 is the magnification of the binocular. The second is the size of the objective or outside lens in millimeters. 10 times the naked eye with a 50mm objective. top of page Like telescopes, objective is the most important factor. It's the same
for binoculars for astronomy. We recommend a minimum of a 50mm objective
lens for astronomy. A 7x50 or 10x50 are very common choices for astronomy.
They offer a large enough objective lens and a magnification that is enough
to bring objects close enough to observe. top of page Even better for astronomy is the larger objective lens binoculars. Many
astronomy binoculars will features objective lenses between 60mm to 100mm
or even more. These larger binoculars will usually require a tripod, as
they are very heavy. The larger objective size binoculars will often have
much more magnification than traditional sized binoculars. Powers of 10x,
15x, 20x or more are common on larger astronomy binoculars. When you have
binoculars of this size and magnification - having a steady hand is usually
not enough. Having them mounted on a tripod will give you the best results.
Many giant binoculars will have a built-in tripod mount or have an adapter
included or sold separately. top of page One of the greatest advancements in binoculars is the Image-Stabilized binocular. Brands such as Canon and Nikon have developed a revolutionary method of stabilizing the image with a tiny microprocessor inside to counter the movement of your hands. These binoculars are amazing for astronomy as you can have all the advantages of high power magnification without the need of a tripod. top of page Tripods All tripods have three things in common: legs. From there they diverge markedly. You'll find aluminum tripods, carbon-fiber tripods and tripods made of steel. There are tripods for binoculars, for cameras and for telescopes. And we have them all. Check out our large selection; your optics will thank you. Catoptrics (formerly anacamptics) is the branch of optics which explains the properties of incident and reflected light, and particularly that which is reflected from mirrors or polished surfaces. Binoculars and reflecting telescopes are catoptric instruments. Catoptrics was also the title of the first known book on the science of optics, authored by Euclid (300 B.C.E.). top of page
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The
Backyard Astronomer's Guide Book Description: But accurate, objective and up-to-date information can be hard to find. Throughout the 1990s, the first edition of The Backyard Astronomer's Guide established itself as the indispensable reference to the equipment and techniques used by the modern recreational stargazer. Now, authors Terence Dickinson and Alan Dyer have produced an expanded and completely updated edition that again sets the standard for accessible and reliable information on one of the world's most popular hobbies. top of page Dickinson and Dyer -- both full-time astronomy writers -- bring decades of experience to their task. They explain why telescopes often perform much differently from what the novice expects. They recommend the accessories that will enhance the observing experience and advise what not to buy until you become more familiar with your equipment. They name brands and sources and compare value so that you can be armed with the latest practical information when deciding on your next purchase. Sections on astrophotography, daytime and twilight observing, binocular observing and planetary and deep-sky observing round out this comprehensive guide to personal exploration of the universe. Dickinson and Dyer's elegant yet straightforward approach to a complex subject makes this book an invaluable resource for astronomers throughout North America. top of page With more than 500 color photographs and illustrations, The Backyard Astronomer's Guide is also one of the most beautiful -- and user-friendly -- astronomy books ever produced. top of page Amazon reviewers say: "This classic introduction to amateur astronomy has gotten a much improved revised edition. Dickinson and Dyer have updated this indispensable resource for the 21st century. This book is divided into three main parts. The first covers the hardware. The authors explain the workings of the different types of scopes and accessories and give suggestions based upon budget and the type of viewing to be pursued. They tell you what hardware is essential, what is nice to have, and what you can live without including new scopes and accessories that have come out since the previous edition. Also covered is how to set up the scopes properly, and what mistakes to avoid setting up a new scope for the first time. The second part is a crash course on the sky, starting with what you can see with the naked eye, observing conditions based on your location, and then how to observe the various objects in the sky with the equipment from the first part. The final part is an introduction to photographing the sky with a camera (film or digital) or a dedicated CCD imager. Coverage includes simple camera on a tripod or barndoor mount setups, piggybacking on a telescope, and thru the telescope photography. Enough to get one started. The text is not the only part of this book to be updated. Hundreds of color photos have been sprinkled liberally throughout this guide. If you are just getting one book before plunging into amateur astronomy, make this the book. It is great for beginning and intermediate amateurs."
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How to Choose Binoculars Most Suitable for Your NeedsThis article has been written to help you learn how to evaluate binoculars and then show you how to choose binoculars based on your budget and the purpose for which you plan to use them. We shall be looking at how binoculars work. Understanding this will help you to understand the different factors that will affect price and the features that are available - usually these revolve around optical quality, magnification power, and portability – before moving on to look at different price categories and justifications for buying a more expensive pair depending on what they will be used for. The overall aim is to prepare you for the task of finding the right pair of binoculars, at the right price, without compromising on features that you may require. top of page How Binoculars Work A pair of binoculars can be seen as two such telescopes, side by side, which together produce an image which has the depth of field that we are used to, rather than just a large flat image. top of page Since the light has been refracted (bent) as it has been directed through the lenses, by the time the viewer sees the image it is back to front, and upside-down. To correct this, two prisms are placed inside the binoculars, between the objective and the eyepiece. It is the presence of these four prisms in the shoulders of the binoculars that give them their squat appearance. top of page Power, Light and Weight The magnification factor tells you how many times larger the object will be magnified – a number of between 4 and 7 is ample for most applications. Any larger than about 9 or 10, and the natural shake of the human hand will be magnified to such an extent that the image becomes difficult to see, and a tripod will be required. top of page Glass also has a tendency to reflect as much as 5% of the light that arrives at its surface back towards the light source. A simple coating was devised to prevent this, by allowing more light to pass through the lens, and less to be reflected back. Since the advent of the original coating, the technique has been refined, and there are several grades of lens coating available. top of page The best result is achieved when multiple layers of coatings are applied, to the front and rear of the lens. Each coating is designed to provide the maximum transmission of light through the lens, and minimum reflection and diffraction, resulting in a brighter, clearer picture than with standard non-coated lens models. top of page Modern lightweight binoculars have also evolved in terms of the use of roof prisms, rather than the traditional Porro prisms. This means that they have no ‘shoulders’ and look more modern. The lack of superfluous casing makes them easy to carry, and substantially lighter than traditional binoculars, however the price tag for higher power models tends also to be more substantial than for the traditional type of a similar magnification. top of page Pricing Justification Plastic lenses, on the other hand, tend to make the binoculars lighter, but will be substantially more expensive for the same grade of picture quality. If the binoculars are to be used in clear conditions, at a low power, then this may be acceptable. If more variation in lighting (i.e. dusk and night use) is expected, then one should opt for better quality optics, and hence a higher price tag. top of page The build quality will also affect the price. More rugged, shock-proof binoculars destined for use in harsher conditions (marine or backpacking) will cost more than those which do not need to be waterproof or shockproof. top of page Uses and Solutions Bird watching glasses need to be good in all light conditions, from dawn to dusk, and even have limited night vision. The same goes for hunting glasses, and in both cases they should be lightweight, but probably with a smaller magnification, and larger objective. top of page High power spotting scopes, or binoculars, where the power exceeds 10x will need to be mounted on a tripod. The best models will be ones with a very large objective lens, suitable for use in many conditions, but will be too heavy and cumbersome for use on the move. top of page Finally, when hiking or orienteering, binoculars will be very useful, but it is important to note that optics are very fragile, and so plastic lenses over glass ones, and a rugged case are probably going to be more important than high power, or the ability to use them at night. top of page As a curio, it is possible to buy, from Zeiss, a pair of binoculars which have a mechanical anti-jog mechanism which allows for extremely high magnification, but without the shake associated with it. They come in at around $4000. Digital binoculars are a cheap alternative, and can be picked up for considerably less ($200), and usually have a built-in camera. They are not perfect optically, with a resolution of around 3 megapixels, but will suffice for the hobbyist. top of page Jargon Explained For example, there are several different descriptions of the coating that has been used (see Power, Light and Weight) to reduce the amount of light reflected back through the lenses during magnification: top of page · C : Some surfaces coated In the last case, one would expect a good quality piece of optics to be able to transmit between 92% and 95% of all available light back to the eye. top of page The “Exit Pupil” is also important and can be calculated by dividing the power by the objective size and yields a value which is very important – it is the diameter of the light fed to the eye. Given that the average human pupil ranges in size from 2mm to 7mm depending on the available quantity of light, it is clear that, in the midday sun, an Exit Pupil value of 4mm (for example) will mean that 50% of the image returned to the eye is lost. top of page By a similar token, if the value is smaller than 7mm for a night scope, then it is not taking advantage of the human anatomy. A word of advice – always use night scopes in the dark, to keep the pupil as wide as possible; this means no, or very low, light around the place that you choose to hide out whilst communing with nature. top of page Finally, if the phrase ‘Eye Relief’ is mentioned, then it refers to the way that the eyepiece is set up with respect to the other optics in the device. Most glasses will come with eye relief between 9mm and 13mm, and is the distance from your eye to the lens before your field of view becomes limited. top of page If you wear eyeglasses, then eye relief above 14mm becomes desirable, since you will already have a certain amount of distance between your eye and your eyeglass lens, which you can not change. Given this, if your chosen optical device has a small eye relief, then you will have a very restricted field of view, and miss out on most of the picture! top of page As you can see when you need to decide how to choose binoculars most suitable for you there are many aspects to consider. Hopefully this article will have made your job easier. For more information on the binoculars available you can visit the relevant links. top of page Binoculars: Frequently Asked Questions
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