James Webb Telescope Black Hole With
The primary mirror of the JWST, the Optical Telescope Element, is composed of 18 hexagonal mirror segments made of gold-plated beryllium which combine to create a 6. 5-meter (21 ft; 260 in) diameter mirror that is much larger than the Hubble’s 2. 4-meter (7. 9 ft; 94 in) mirror. Unlike the Hubble, which observes in the near ultraviolet, visible, and near infrared (0. 1 to 1 μm) spectra, the JWST will observe in a lower frequency range, from long-wavelength visible light through mid-infrared (0. 6 to 27 μm), which will allow it to observe high redshift objects that are too old and too distant for the Hubble to observe. The telescope must be kept very cold in order to observe in the infrared without interference, so it will be deployed in space near the Earth–Sun L2 Lagrangian point, and a large sunshield made of silicon- and aluminum-coated Kapton will keep its mirror and instruments below 50 K (−220 °C; −370 °F).