SOFI at the NTT

SOFI is the infrared spectrograph and imaging camera on the New Technology Telescope, at La Silla Observatory. It looks like a piece of kitchenware, but this is because the optical system and detector are cooled to around -200°C by means of the closed cycle cooler attached to the enclosing vacuum vessel. A co-rotator system feeds electrical cables plus gas and fluid hoses to the instrument and rotates with it as the telescope tracks objects on the sky.