- Universal Compatibility: Designed to fit a wide variety of telescopes, including reflectors, refractors, Dobsonian, Mak Cas, and SCT models with an outer diameter of 63 to 89 mm. Easily attach the focusing mask using just three screws. - Precise Focusing: The Bahtinov mask removes the uncertainty often associated with focusing. It allows you to achieve optimal focus quickly, even in challenging visual conditions. - Secure Hold: The mask is equipped with three robust metal columns that grip the telescope securely, preventing any slipping and ensuring perfect centering. This 3-pillar design enhances central alignment and extends compatibility across various telescope models. - Diffraction Pattern: The innovative focus fish bone design acts as a series of artificial trusses. As light passes through the mask, it is refracted in three directions, producing three distinct pairs of beams. When adjusting focus, the beam patterns will shift until they align perfectly, signaling the ideal focus point. Use Scenarios: 1. Astrophotography: Achieve precise focus for capturing stunning images of celestial objects, ensuring clarity and detail in your photographs. 2. Observation: Improve your stargazing experience by quickly achieving sharp focus on planets and nebulae, making your sessions more enjoyable and productive. 3. Educational Purposes: Perfect for educators and students in astronomy, this mask helps demonstrate the principles of optics and focusing in a hands-on way.