The VISTA infrared camera

We describe the integration and test phase of the construction of the VISTA Infrared Camera, a 64 Megapixel, 1.65 degree field of view 0.9-2.4 micron camera which will soon be operating at the cassegrain focus of the 4m VISTA telescope. The camera incorporates sixteen IR detectors and six CCD detectors which are used to provide autoguiding and wavefront sensing information to the VISTA telescope control system. imaging performance between 0.9µm and 2.5µm. The camera is roughly 3m in length, has a total mass of 2,900kg, and will be the largest infrared camera ever built, both in terms of field of view and number of detector pixels. The wide-field design of the telescope requires active control of the position and tilt of the secondary mirror, and the camera also includes a pair of onboard curvature sensors as well as frame-transfer CCDs for autoguiding. In the first instance VISTA will be operated as a single instrument telescope, and so the IR Camera is designed for continuous operation between scheduled yearly downtimes for essential maintenance. The camera is now essentially complete in the assembly, integration and verification (AIV) facility at the Rutherford Appleton Laboratory undergoing final testing and awaiting shipping to Chile for integration and commissioning which is now expected to commence in November of 2006. This paper will cover the evolution of the design 5 into the final build, some lessons that can be learned from the build process of such a large cryogenic instrument, and those performances of the instrument which have been measured in the laboratory.