When did Johannes Kepler invent the telescope?

Johannes Kepler did not invent the telescope. The first telescopes were developed in the Netherlands and are credited to three individuals: Hans Lippershey and Zacharias Janssen, who were spectacle makers in Middelburg, and Jacob Metius of Alkmaar.

Galileo developed improvements on those early refracting telescope designs and Kepler developed improvements on Galileo's design.