Reflecting upon the process of making lenses then in vogue, young Huygens and his brother Constantine attempted a new method of grinding and polishing, whereby they overcame a great deal of the spherical and chromatic aberration.

With this new telescope a much clearer field of vision was obtained, so much so that Huygens was able to detect, among other things, a hitherto unknown satellite of Saturn.
It was these astronomical researches that led him to apply the pendulum to regulate the movements of clocks.

The need for some more exact method of measuring time in his observations of the stars was keenly felt by the young astronomer, and after several experiments along different lines, Huygens hit upon the use of a swinging weight; and in 1656 made his invention of the pendulum clock.

The year following, his clock was presented to the states-general.

Accuracy as to time is absolutely essential in astronomy, but until the invention of Huygens's clock there was no precise, nor even approximately precise, means of measuring short intervals.
Huygens was one of the first to adapt the micrometer to the telescope--a mechanical device on which all the nice determination of minute distances depends.