A Barlow lens is powerful in two ways. Firstly, it effectively provides an alternative focal length (i.e. magnification) for any eyepiece it is paired with. Secondly, by so doing, it doubles the selective capability of an astronomer’s armoury of eyepieces. Magnification is something that needs to be manipulated at all times to handle differences in atmospheric conditions and field of vision requirements, to name just two. Any additional capability of doing this, such as a Barlow lens, is a valuable asset.
Telescopes themselves (particularly refractors and compound designs) have been taken to great heights regarding superlative colour correction. Eyepieces, too, have become highly sophisticated multi-element tools that waste little of an object’s lucidity.
Barlows have not been left behind. This new Barlow is a compound four-element lens. It provides efficient field correction and achromatic performance that can match other highly specified optics in the light path. It comes as a 1.25-inch fitting push-fit and sports a 28.5mm filter thread for standard filters. The eyepieces it caresses are held firm but gently with a brass collar clamp.
For more information, contact Optical Vision Ltd. www.opticalvision.co.uk