1pc D40 Achromatic Objective Lens for DIY Refractive Astronomical Telescope 40mm Dia 205mm FL Adhesive Blue Film(41F156 Green Film)

Achromatic objective lens devised for self-made refractive telescopes, ensuring clear and sharp images. Features a 40mm diameter and a focal length of 205mm, perfect for amateur astronomers looking to enhance their viewing experience. Coated with an adhesive blue film, this lens minimizes chromatic aberration for improved optical performance. Easy to assemble: simply position the thin side of the lens towards the scene and the thick side towards the mirror tube. Ideal for DIY enthusiasts and astronomy lovers, this lens is a must-have accessory for building your own telescope.