View looking down the barrel of the WISE telescope. This image shows the 40 cm WISE primary mirror, which is the largest optical element in the WISE system. This image shows the initial assembly of the optics. After this initial check-out, the optical system will be disassembled for painting and the aluminum mirrors will be given a thin Gold coating. Gold is a good reflector in the infrared and is often used to coat IR optics.

Image Credit: NASA/JPL-Caltech/SSG