Galileoscope, LLC, is the creator of the Galileoscope, a high-quality, low-cost telescope kit developed by a team of astronomers, optical engineers, and science educators for the International Year of Astronomy (IYA) 2009. It was also a cornerstone project of the International Year of Light (IYL) 2015.

The Galileoscope is a 50-mm (2-inch) diameter, 25- to 50-power achromatic refractor whose assembly takes only minutes and requires no tools, tape, glue, or other nonsense. In contrast to other inexpensive telescope kits, the Galileoscope can be used effectively both in the classroom to investigate how lenses make images and outside under the stars as a tool for cosmic exploration. Even from brightly lit cities, with the Galileoscope anyone can see the celestial wonders that Galileo first glimpsed 400 years ago and that still delight stargazers today: lunar craters and mountains, four moons circling Jupiter, the phases of Venus, Saturn’s rings, the Pleiades star cluster, sunspots (with a safe solar filter covering the aperture, of course), and more.

Teaching materials developed for use with the Galileoscope, including an educator’s guide on how lenses and refracting telescopes work and an observer’s guide on suitable astronomical targets for the Galileoscope, are freely available online. Numerous science-education efforts around the world incorporate the Galileoscope into their curriculum, including the U.S. National Optical Astronomy Observatory’s Teaching with Telescopes program and the international Galileo Teacher Training Program (GTTP).

Of the more than 250,000 Galileoscopes distributed so far, about one-third have been sold via ~30,000 small orders from individuals, and about two-thirds have been sold via ~600 large orders from institutions. More than 20,000 kits were donated to schools, some in the U.S. and some in less developed countries, chiefly in Africa and the Middle East.

As of 2019, the project has been transferred to Explore Scientific, LLC, which assumed responsibility for production, marketing, and distribution of new Galileoscope kits.