The ability to zoom with your eyepiece provides an exceptional way to increase details without sacrificing the chance of moving your telescope off target while switching eyepieces.
Zoom also allows you to choose the best magnification for detecting and viewing deep sky objects. This is especially useful in light-polluted areas. By adjusting the zoom, you can achieve the darkest sky, the best field of view and the best resolution of sky objects.
The twist-up eyecups twist down for people who wear glasses. A rubber grip allows for a smooth zooming action, especially in cold, damp weather.
To calculate the magnification of this eyepiece, use the following formula: telescope focal length (mm) / eyepiece focal length (mm). For example, for a 640mm focal length and a 25mm eyepiece, the magnification is 25.6x (640 / 25 = 25.6). Please keep in mind that magnification also depends upon the lowest / highest useful magnification of the telescope. Check out individual telescope pages for highest / lowest useful magnification calculationsrubber knurled grip ring for focal length adjustment round out the aesthetic features of this high-quality, high-performance eyepiece