Astronomy, as we usually think of it, involves the use of a telescope in order to better see distant objects in the sky -- whether it's the small-scale amateur version, a bigger telescope housed at an observatory or one stationed in space, like the Hubble. Although Galileo Galilei is sometimes credited as the inventor of this amazing tool, we can actually credit three lens and instrument makers in the Netherlands with the first patent applications for the refracting type. Soon after, Galileo improved upon these concepts. Then in 1668 -- 60 years later -- Isaac Newton built the first actual refracting telescope.
Of course telescopes have made locating celestial objects much easier, but people were making important astronomical discoveries long before its invention. For example, astronomers were employing the astrolabe -- essentially a type of manual calculator used to help locate the stars, sun, moon and planets -- since at least 150 B.C. And even after telescopes became ubiquitous, astronomers continued using other means to discover and predict astronomical phenomena. In this list, we'll run down some astronomical discoveries that had nothing to do with the telescope.