Astrozap Bahtinov Focusing Screen
Like the Focusing Cap, the Astrozap Bahtinov Focusing Screen is made of solid sheet aluminum (unlike others’ offerings made of plastic and not nearly as durable) and also powder coated to resist corrosion and retain its attractive appearance. Also, like the Astrozap Focusing Cap, Astrozap has many sizes of Focusing Screens to fit telescopes in most popular sizes. The Astrozap Focusing Screen is designed with plastic screws mounted in rubber grommets that adjust to fit the outside of the optical tube, holding the screen in place without marring or scratching the tube’s finish. The Focusing Screen produces the same unique Bahtinov diffraction pattern as the Focusing Cap and enables the same result: best focus every time.
Every observer (light side) and imager (dark side) know that sharp focus is essential for getting the most out of precious telescope time. Recently, the Bahtinov-style mask has overtaken the Hartmann mask in popularity for the reason that the Bahtinov diffraction pattern’s unique display provides a more accurate guide to determining the optimum focus point. For light side astronomy, the Bahtinov mask enables faster, more precise focusing when changing eyepieces. For dark side astronomy, where camera focusing is critical to obtaining the best images, the Bahtinov mask eliminates the guesswork in locating the point of best focus and permits quick adjustment when changing filters or tweaking focus as the imaging run continues through the night.