Why is this Space Telescope so Tiny?

If you want to take a look through a similar telescope, follow this link: Optical Engineer Rik ter Horst shows us how he makes very small telescopes (at home) which are intended for use in micro-satellites. Contents: 0:00 Intro 1:06 About telescopes and focal length 3:35 The Cassegrain telescope 4:38 The Schmidt-Cassegrain telescope 5:18 The monolithic telescope concept 6:30 Rik ter Horst Interview 10:25 Riks’ polishing setup 13:51 About manufacturing aspherics 16:50 Advantages of solid telescopes 17:49 Dreaming about a VLTT ORESAT PROJECT CORRECTION. I was notified that the name of the university behind the OreSat project is erroneous: It is the “Portland State University“ (), not University of Portland. Sorry about that! Direct link to the Oresat project: Rik published details about the 1993 version of this type of telescope on cloud