What is a Barlow Lens?

A Barlow lens is an additional lens that multiplies the total magnification of a telescope. Typically, Barlow lenses are usually 2x or 3x in power, therefore, doubling or tripling the overall power. They can be handy to get a closer…

What is the aperture of a telescope?

The aperture refers to the diameter of the largest optical element. In a refractor telescope, it’s the diameter of the objective lens. In a reflector telescope, it’s the diameter of the primary mirror. The aperture determines how much light gathering…