| This is a very good quality medium power eyepiece for lunar observing, resolving globular clusters, picking up detail in the more compact emission and reflection nebulas, etc. This 15mm focal length is a good eyepiece for filling in the gap between the 26mm eyepiece that comes standard with most telescopes and a high power planetary/binary star splitting eyepiece. It has a somewhat short eye relief that will limit the field for eyeglass wearers. Those who must wear eyeglasses while observing due to severe astigmatism would probably be better off using a Barlow and a longer focal length eyepiece with longer eye relief to reach this focal length, rather than buying this eyepiece for use on its own. It is parfocal with other Series 4000 eyepieces except the 14mm UWA, 32mm and 40mm SWA, and 40mm and 56mm Plössls. It will work well with any telescope type, at any focal ratio. |