– Essential for precise focusing of astronomical telescopes. – Diffraction spikes eliminate guesswork for quickly and precisely achieving accurate focus, especially when imaging. – High-quality Bahtinov mask with meticulously crafted grooves to produce symmetrical diffraction spikes. – Durable construction for long-lasting use during your astronomical endeavors. – Laser-cut from laser-grade acrylic with a thickness of 1.5mm, providing rigidity and durability. – Outer diameter of 114mm, suitable for telescopes with an aperture of 80-150mm.