In 1663, Scottish astronomer James Gregory proposed the design of a reflecting telescope, although he never actually built it.
Then later, in 1668, English mathematician Sir Isaac Newton developed the first functional reflecting telescope with a 1.3-inch mirror and a 6-inch tube.
Now today, reflector telescopes, commonly known as "Newtonians," use two mirrors - a large primary one at the bottom and a small secondary one at the top. Light enters the tube, reflects off the primary, and is directed to the eyepiece by the secondary mirror. In the past, amateur astronomers often built their own reflectors, but now high-quality models are readily available and affordable. Reflectors are generally less expensive than other types of telescopes, making them a good choice for those on a budget. However, the largest telescopes are also reflectors, and if size and weight are not a concern, a 12-inch or bigger reflector might be the right choice for you.
And Keep these in your mind
- Reflectors do not show color fringes around objects, making them ideal for observing even the brightest objects.
- Reflectors are less expensive than other telescope types due to requiring the polishing of only one surface when working with a mirror. Telescopes with apertures of over 6 inches are mostly reflectors or compound telescopes.
- The secondary mirror in reflectors scatters a small amount of light from bright areas into darker ones. This is generally not noticeable unless observing planets or bright nebulae under high magnification.
- Newtonian reflectors suffer from a defect called "coma" that causes stars at the edge of the field of view to appear comet-like. Observers usually center all targets to compensate for this.
- Reflectors are sensitive to bumping or jostling during transport due to how the mirror attaches to the tube. To ensure proper functioning, skygazers collimate their telescopes (adjust the mirrors) before each observing session.