 So, you've got your lenses with your refractors, and you've got your mirrors with your reflectors. So why can't we have both? Why can't these optics all just get along? Well, if you want to look at a really big chunk of the sky, these cats are going to impress you. Cata diopteryx, that is. This is your space pod for May 22, 2015. Unlike our other two types of telescopes, refractors and reflectors, cata diopteryx telescopes have actually seen a majority of their development occur in the last 200 years. And very interestingly, cata diopteryx optical systems were originally developed not to collect light, but actually to amplify light. French physicist Augustine John Fresnel developed cata diopteryx systems to help lighthouses project light further in the 1820s. Then in the 1850s, Leon Foucault perfected a cata diopteryx microscope. A cata diopteryx telescope is, at its heart, a reflector. Much like a reflector, the primary mirror is what collects the light. But instead of a secondary mirror placed above the primary, a specially curved lens is placed. This allows the light to travel to the eyepiece. Although in some cata diopteryx telescopes, the secondary is a specially curved mirror. One of the advantages of this is that you're able to have that light bucket design that you get with reflectors. With a specially curved lens or mirror as your secondary, instead of a narrow patch of the sky to view like in a reflector, you get a larger field of view, meaning more sky within your view. The secondary lens or mirror is also curved. This allows for compensation of the errors to be expected in the most refractor or reflecting telescopes. This makes for extremely precise viewing. So you've got the advantage of a reflector with that ability to gather volumes and volumes of light. But you've also got that wonderful advantage of a refractor with precise viewing. In addition, you get to look at a larger patch of the sky than either of those two telescopes. Schmidt casigrades are the best known and most often used of cata diopteryx designs. They use that specially curved lens for their secondary. Max sudobs, affectionately known as max, are quite popular as well, known for their epic abilities to allow high magnification from compact designs. Courtesy of the choice to use a mirror for their secondary. In addition, because of their construction, max tend to be durable little beasts. Thanks for watching this Facepod. I'm Jared Head. Don't forget to comment, subscribe, and help contribute to our patreon. Next week we'll be taking a look at some options that you may want to consider in addition to just getting a telescope. So, until the next Facepod, keep exploring.