All about telescopes

Contrary to popular belief, the magnification of a telescope is not its most important characteristic. It is actually the amount of light collected and the angular resolution of the telescope that is important. Imaging zooming into a low-resolution image. You will only see blurry outlines of the things you are looking closely at. On the other hand, if you have an extremely high resolution image, you can keep zooming in and the details will remain clear. There are two main types of telescopes: refracting and reflecting. A refracting telescope uses lenses, much like an eye, to focus the light, while a reflective telescope uses a large, curved mirror to focus light to a secondary mirror, which directs the light to a person’s eye, allowing them to see. Almost all astronomical telescopes are reflecting telescopes, because large lenses are fragile and difficult to produce and attach to a telescope. Reflecting telescopes also have the advantage of being able to separate the one large mirror into smaller mirrors that work together, making them easier to produce. The James Webb telescope, our most advanced space telescope, uses 18 mirrors that combine to form a mirror that is 6.5 meters across. It has been used to look back almost to the very beginning of the universe, helping scientists discover more about universal formation and the big bang.

James Webb Space Telescope. Image courtesy of Smithsonian