| 1608 | Dutch Telescope | First device identified as a telescope. Made by Hans Lippershey and was a refracting telescope with convex objective and eyepiece lenses. |
| 1609 | Galilean Telescope | Galileo Galilei improved the invention, and this telescope could magnify objects up to three times. |
| 1611 | Keplerian Telescope | Invented by Johannes Kepler, it used a convex objective lens and a convex eyepiece. Allowed for higher magnification and a larger field of view. |
| Late 17th Century | Newtonian Telescope | Isaac Newton developed a telescope that used mirrors – a reflecting telescope. This type of design minimised the colour distortion. |
| 18th Century | Herschelian Telescope | This simpler design incidentally made by William Herschel has a slight tilt in the mirror to avoid the observer’s head from obstructing the viewing. |
| 19th Century | Cassegrain telescope | Laurent Cassegrain designed the light path which involves reflection off the back of the primary mirror and a hole in the centre of primary mirror. |
| Mid 20th Century | Radio telescopes | These could observe radio waves from space. Radio telescopes opened a new window into the study of the universe. |
| Mid 20th Century | Space Telescopes | To escape the distorting effects of Earth’s atmosphere, telescopes like Hubble were sent to orbit. |
| Early 21st Century | Digital/Robotic telescopes | More efficient to observe as they could sample multiple wavelengths, not just visible light. Greatly increased data availability. |
| Current | Extremely Large Telescopes (ELT) | Under development, these telescopes are ground-based and have significantly larger mirrors with diameters up to 39 metres. |
