WFCAM, the Wide Field Infrared Camera, was delivered to UKIRT in July 2004. WFCAM is an ambitious instrument that consists not only of a cryogenic camera holding four state-of-the-art detectors, associated electronics and computing, but also a large optical system for the UKIRT telescope including a new f/9 secondary mirror and a complete auto-guiding system.
The camera uses4 Rockwell Hawaii-II (HgCdTe 2048x2048 pixel) arrays spaced by 94% in the focal plane, such that 4 separately pointed observations can be tiled together to cover a filled square of sky covering 0.75 square degrees with 0.4 arcsecond pixels. A microstepping mode allowing accurate pointing shifts of typically 1/2 or 1/3 of a pixel, followed by subsequent interleaving of the frames, can provide 0.2 or 0.13 arcsecond per pixel sampling.
WFCAM has been designed specifically to carry out large-scale survey observations.
The camera has been designed to maximise survey speed at J, H and K (1.2, 1.65 and 2.2 micron) wavebands while retaining excellent image quality over a large field of view. With about half the available observing time on UKIRT being allocated to WFCAM, surveys unprecedented in depth and size will be possible. Initially these surveys are being carried out under the guidance of the UKIRT Infrared Deep Sky Survey (UKIDSS) consortium.
Both large surveys and targeted observations will be made. The surveys will be highly influential in the study of high-redshift clusters, obscured quasars and active galactic nuclei, brown dwarf stars and in setting low-mass limits to star formation. Large infrared atlases and catalogues of data will give UK and other astronomers from ESO member countries an advantage in access to other 8 metre telescopes by identifying the most interesting targets for more detailed study.
A substantial data centre and an archive has been established within the UK wide-field astronomy groups CASU at Cambridge and the WFAU in Edinburgh respectively. The raw data are transfered to the UK for full off-line processing in Cambridge, and from there to the WFCAM Science Archive in Edinburgh. The WFCAM Science Archive is the primary data source for both UKIDSS results and PATT project data.
More technical information about WFCAM is available from the WFCAM project pages, and detailed information about the use of WFCAM on the telescope can be found at the WFCAM Instrument page at UKIRT.