Introduction

What do the numbers on the telescope eyepiece mean?

What do the numbers on the telescope eyepiece mean?

The numbers refer to the focal length of the eyepiece. The higher the number, the lower the magnification. You should always start with the eyepiece that has the highest number (lowest power); that will make it is easier to find objects.

The focal length of the eyepiece is also needed to calculate the overall magnification of the telescope (focal length of telescope / focal length of eyepiece = overall magnification).