I knew about refracting telescope, reflecting telescope and radio telescope, but have never heard about X-ray and Gamma-ray telescope. Today I came to know about it when I searched with this keyword “how many types of telescope?” online?
Both telescopes uses different rays to generate images of distant objects located somewhere in space. X-rays are used by X-ray telescope and gamma rays are used by gamma-ray telescope. If you want to study stars, sun and supernovas, X-ray telescope is the best option to capture plenty of X-rays emitted by stars and supernovas. However gamma-ray telescope captures gamma-rays that help identifying events happening in somewhere in outer space such as supernova, black holes and pulsars. Both telescopes generate good images at higher elevation because they can easily read the rays coming from distant objects. Moreover, earth’s atmosphere becomes thinner at high altitudes, that diminishes atmospheric technical problems that generally create troubles in generating images.
Source: http://www.differencebetween.info/different-types-of-telescopes