Product Description for Bahtinov Focus Mask for Telescopes Achieve pinpoint precision in your astrophotography with the Bahtinov Focus Mask for Telescopes. This essential tool is designed to take the guesswork out of focusing, ensuring that your celestial observations and photographs are sharper and clearer than ever before. Discover the features that make this focus mask an indispensable accessory for astronomers and photographers alike: Wide Range of Applications: Compatible with all types of telescopes, including mirrors, refractors, Dobsonians, Mak-Cassegrains, and SCTs. Simply measure your telescope tube size and choose the appropriate mask size to enjoy hassle-free installation and enhanced focusing capabilities across various telescope models. Provide Telescope the Best Focus: The Bahtinov mask simplifies the focusing process, eliminating uncertainty and mitigating vision conditions to deliver the best possible focus quickly and effortlessly. This ensures that your telescope is perfectly aligned for observing detailed celestial images and capturing stunning astrophotography. 3 Metal Posts: The mask is equipped with three metal posts that gently and securely grip the telescope tube. These posts have scratch-resistant silicone covers to protect the surface of your telescope, preventing slippage and ensuring that the mask remains perfectly centered during use. 3 Posts Installation and Lightweight Design: The innovative 3-post mount design accommodates a wider range of telescopes while keeping the mask centered. Its lightweight construction ensures that the balance of your telescope is not disrupted, allowing for smooth and stable observations. Scope of Application: Designed to fit telescope objective lenses with an outer diameter range of 100‑140mm (with a 1‑2mm margin for manual measurement error). This ensures versatility and adaptability across a spectrum of telescope configurations, making it a versatile tool for both amateur and professional astronomers. Elevate your stargazing and astrophotography experience with the Bahtinov Focus Mask for Telescopes. Its practical design, ease of use, and compatibility with multiple telescope types ensure that you achieve optimal focus every time, capturing the universe in stunning detail. Whether you're observing planets, stars, or deep-sky objects, this focus mask is your key to clearer, more precise astronomical imaging.