Telescope, device used to form magnified images of distant objects. The telescope is undoubtedly the most important investigative tool in astronomy. It provides a means of collecting and analyzing radiation from celestial objects, even those in the far reaches of the universe.

670,616,629 miles per hour

Reflecting telescopes have many advantages over refracting telescopes. Mirrors don’t cause chromatic aberration and they are easier and cheaper to build large. The are also easier to mount because the back of the mirror can be used to attach to the mount. Some telescopes use a combination of mirrors and lenses.

Isaac Newton

The Best Telescopes for Beginners

• Our pick. Celestron NexStar 5SE Telescope. The best telescope.
• Budget pick. Astronomers Without Borders OneSky Reflector Telescope. A scope without the GPS.
• Also great. Sky-Watcher Traditional Dobsonian Telescope (8-inch) Less portable, but amazing image quality.

A low magnification of around 50x will show you the whole moon and give you the “big picture.” But to see the moon at its best, try a high magnification, at least 150x. The moon can tolerate high magnification better than any object in the sky.

Most telescopes, and all large telescopes, work by using curved mirrors to gather and focus light from the night sky. The bigger the mirrors or lenses, the more light the telescope can gather. Light is then concentrated by the shape of the optics. That light is what we see when we look into the telescope.

A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens as its objective to form an image (also referred to a dioptric telescope). A refractor’s magnification is calculated by dividing the focal length of the objective lens by that of the eyepiece.

They focus the light and make distant objects appear brighter, clearer and magnified. This type of telescope is called a refracting telescope. Most refracting telescopes use two main lenses. The largest lens is called the objective lens, and the smaller lens used for viewing is called the eyepiece lens.

Refracting telescopes use convex lenses, at the front of a tube, to gather and focus incoming light. The image formed is magnified for the viewer through an eyepeice lens at the back end of the tube. Reflecting telescopes make use of a primary concave mirror to gather light.

optical telescopes

(b) Most simple refracting telescopes have two convex lenses. The objective forms a real, inverted image at (or just within) the focal plane of the eyepiece. This image serves as the object for the eyepiece. The eyepiece forms a virtual, inverted image that is magnified.

In a refractor, light enters the telescope near the objective lens. The objective lens is a convex lens. This lens converges the light. The rays of light converge at the focal point.

A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. Although reflecting telescopes produce other types of optical aberrations, it is a design that allows for very large diameter objectives.