ZERODUR microcrystalline glass is a special type of microcrystalline glass with extremely low coefficient of thermal expansion, excellent uniformity, high mechanical stability, and customizable shape and lightweight characteristics. These characteristics make it an ideal material for manufacturing high-quality astronomical telescopes. The applications of ZERODUR microcrystalline glass in the field of astronomy include:

1. Making primary and secondary mirrors: ZERODUR microcrystalline glass is used to manufacture primary and secondary mirrors for telescopes, as these lenses require extremely high shape stability and optical quality.

2. European Large Telescope (ELT): As the world's largest optical telescope, the main mirror of ELT uses ZERODUR microcrystalline glass to maintain its stability under extreme temperature changes.

3. Ground and space telescopes: ZERODUR microcrystalline glass is widely used in various ground and space telescopes, including backup lenses for the Hubble Space Telescope.

4. Laser guided telescope: A telescope used for adaptive optical systems that requires extremely high optical accuracy, which can be provided by ZERODUR microcrystalline glass.

5. Solar Telescope: Solar telescopes are used to study the sun and require materials that can maintain stability under extreme high temperatures.

6. Radio Telescope: Although radio telescopes do not directly use lenses, ZERODUR microcrystalline glass can be used to manufacture precise support structures and positioning devices.

These applications demonstrate the importance and versatility of ZERODUR microcrystalline glass in the field of astronomy, particularly in improving telescope observation capabilities and exploring the universe.