6. Mechanics and Cryogenics

The drawing presented in Figure 6 suggests a cryo-mechanical design based on a cylindrical vacuum shell, with total size dictated by total length of the optical system and wheels diameter. The operations at the derotated Nasmyth focus implies the rotation of the instrument itself, making unpractical the use of liquid cryogenics for cooling and mantaining the operative temperature. Instead, we based the cryogenic system on a closed cycle cooler. A number of external motors take care of wheels and slides positioning, depending on the requirements of the specific observing mode.