Subaru telescope

Corning produces glass for the Subaru Telescope mirror. Weighing 271 and more than 26 feet across it is one of the largest pieces of glass ever made. 

Fig. 4.4 A comparison of the reflectivity of Amalthea, Thebe, Callisto and Asteroids. Amalthea and Thebe have reflective spectra similar to those seen in regions of CaUisto where there is little water ice black line). The dip in the spectrum around 3 pm indicates the presence of water containing minerals. Copyright Subaru Telescope, National Astronomical Observatory of Japan (NAOJ)...

In Fig. 4.4 a comparison of the reflectivity of Amalthea, Thebe, Callisto and Asteroids is given (obtained with the 8.2 m Subaru Telescope). Thebe is a small satellite of Jupiter (55 x 45 km), Amalthea is one of the inner satellites of Jupiter (mean diameter about 165 km). In this figure the signature of water is clearly seen. Amalthea radiates more energy than receiving, maybe it is heated by electric currents in Jupiter s magnetosphere. 

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