Barlow Lenses of a telescope

Barlow lenses were invented and developed by Peter Barlow and consequentially bear his name. The lenses are not only used in telescopes but also in microscopes to serve the purposes of medicine, science, etc. this type of optical lens is usually used in combination with other different types of optics as well as optical systems. The result of such use is a substantial increase of the focal length of the system where Barlow lenses are used. Barlow lenses are widely used in telescopes. It is a very efficient way of increasing the magnification of your tool. The lens is simply…

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Telescopes types: optical schemes

There are three different types of telescopes: reflector, refractor and catadioptric. Each type has its own advantages and disadvantages and suitable for different cases. This article is going to help you to understand, which is suitable for you. So, let`s see, what`s better: telescope reflecting or refracting, or catadioptric, maybe? Refracting telescopes A refractor, or a lens telescope, is the oldest type of telescopes. It was invented in 1609 by Galileo Galilei and was updated in consequence. Firstly, a refractor used two lenses: convex as an objective and concave in an eyepiece, that caused spherical and chromatic aberrations. This scheme…

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Binoculars with night vision

How does night vision binoculars work? Usually, people use night vision devices for hunting, terrain orientation, for watching night animals and so one. In other words, they use it in outdoor. There must be the moonlight or light of stars. The principle of night vision devices work is the increase of rushlight, which is not enough for our eyes. Any night vision binocular does not work in absolute darkness without special assistance. If you stay in a closed room without windows or any least sources of light, your night vision device won’t help you if only it uses infrared light.…

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What is a walkie-talkie?

Guess what: a portable device which can transmit your voice through the air, but is not a mobile phone? It seems you’ve heard something about an outdated appliance called “radio”… wait a minute! Does it still exist? Oh, yeah! It exists and not going to die! Walkie-talkies versus cell phones Two-way radios are now popular and able to replace a mobile phone in some cases. Here are several reasons to use a walkie-talkie: In work groups, when people need to connect to each other immediately, a cell phone does not fit. A radio works differently from a mobile phone: the…

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