A telescope is an instrument for collecting radiations or light from the distant objects in space.
Telescopes have been one of the most awe-inspiring instruments to not only the ardent scientists and astronomers, but to almost every human being. To be able to view fascinating objects billions and billions of miles away from us is truly a phenomenal experience that this instrument provides.
Visible light, the light humans see is only a tiny part of the huge range of electromagnetic waves the universe sends us. But stars like the Sun are especially good at giving off visible light, so visible light telescopes, also known as optical telescopes are extremely useful for studying the stars. Visible light is the middle range wavelength of electromagnetic spectrum. Short wavelengths include X-rays and gamma rays. Longer wavelengths include microwaves and radio waves.
Various telescopes differ from each other as they cater to observe differing types of electromagnetic radiation (EM). Although optical telescopes are the type most commonly used for stargazing and amateur astronomy by observing visible portion of light (waves) in electromagnetic spectrum, lot more astronomical research is done on telescopes that look at wavelengths other than that of visible light. Each of these wavelength ranges shows us something unique about the universe and allows us to view events and objects which are beyond the visibility of human eyes.
People have been looking to the sky to understand astronomical objects for much of human history. In fact, the earliest telescope can be traced all the way back to 1608. The first telescopes used a convex objective lens at one end of the telescope and a concave eyepiece as a way gather more light than can be done by just looking at something with the naked eye. Sir Isaac Newton is given credit for the first usable reflector telescope in 1668 by incorporating a small mirror to reflect the light to an eyepiece on the side of the telescope. The basic technology of optical telescopes, using lenses and mirrors to collect light, hasn’t altered much over the centuries, but the way they are used in combination has.
Telescopes can be categorized in several ways. While some are classified according to their specification, ranging from professional to amateur, others are classified by the determining which portion of the electromagnetic spectrum it deals with.
There are large varieties of telescopes available, although the safest bet would be the optical telescopes or visible light telescopes. In other words, these telescopes deal with middle range of electromagnetic spectrum, the light that can be seen with the eyes. Optical telescopes are basically focus on the visible light of the electromagnetic spectrum. Lens and mirrors are imperative to achieve the motive of this astronomical invention. The telescopes which focus on the longer wavelength of EM spectrum are Radio Telescopes and Infra-Red Telescopes and those focus on shorter wavelength are X-ray and Gamma ray Telescopes.
We’ll delve deeper into the different types of telescopes in different areas of this site.