barlow lens

A Barlow lens is an optical device used mainly in telescopes and microscopes to increase the effective focal length of the instrument. By doubling or tripling the magnification of the eyepiece, it allows for closer views of distant objects like stars or planets. This means you can see finer details without needing to change the eyepiece. Named after the inventor Peter Barlow, these lenses are especially useful in astronomy to enhance image quality and provide more magnification options, making them a popular accessory for amateur astronomers.