Specialty Glass helps Researchers Observe the Expanding Universe

Specialty glass plays a key role in uncovering the far-reaching answers of space. For HEDTEX (Hobby–Eberly Telescope Dark Energy Experiment) at Austin McDonald Observatory, 156 state-of-the-art spectrographs will serve as the eyes into the universe’s distant past to map the three-dimensional positions of one million galaxies. These spectrographs are using optical mirrors based on BOROFLOAT® glass, the floated borosilicate glass made by specialty glass expert Schott. They will capture the full spectrum of light, measure the distances between galaxies at different times in the early universe, and reveal its composition. With those measurements, scientists can deduce the rate of the universe’s expansion and further understand the physics of dark energy.

BOROFLOAT®’s exceptionally high transparency, outstanding visual quality and optical clarity, and its outstanding thermal resistance are the key performance features helping to observe the universe. The very good temperature stability of this glass is crucial to the HETDEX project because the Hobby-Eberly Telescope, the world’s third largest optical telescope, located more than 6,600 feet above sea level, experiences seasonal temperature and weather fluctuations throughout the year, including snow in the winter and hot sunshine throughout the summer. Thanks to the extremely low coefficient of thermal expansion, BOROFLOAT® resists the challenging expansion and contraction forces that such change of temperatures would typically cause, ensuring high resolution and consistency in researchers’ observation results.

Schott’s specialty glass boasts high chemical durability and excellent mechanical strength mainly due to the addition of higher amounts of boron oxide in its composition, which strengthens the chemical bonds within the glass network. The added boron oxide gives BOROFLOAT® glass a low light refraction behaviour, which together with the material’s superior transmission is a key requirement for precise spectrograph measurement results.

BOROFLOAT® glass is made of pure raw materials, resulting in an extremely low-iron impurity level for float glasses. The sum of it guarantees exceptionally high transmission values. In fact BOROFLOAT® is the industrial glass with the lowest level of iron impurity of all float glass materials in the market.