This 40mm eyepiece is a great low power / very wide field of view eyepiece, perfect for scanning the Milky Way star clouds or large star clusters and nebulae, viewing whole constellations and using as a finder scope to locate objects for more detailed viewing.
The Plössl eyepiece results in crisp, clear viewing. It provides edge-of-field sharpness, low astigmatism and low spherical aberration.
The multi-coated optics allows for optimum image contrast and light transmission
The eyeguard folds down for people who wear glasses, shielding them from coming into contact with the metal eyepiece housing.
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 6mm eyepiece, the magnification is 106.7x (640 / 6 = 106.7). 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 calculations