uv -plane(yoo-vee ) Unlike a conventional telescope, a radio interferometer cannot produce an image of the sky directly. Instead it measures the Fourier transform of the sky brightness distribution in a plane perpendicular to the direction of observation. A measurement on a particular baseline corresponds to a point on this plane with coordinates u and v , at a distance from the origin equal to the projected length of the baseline measured in wavelengths. The uv -plane is sometimes called the aperture plane, and a good coverage of points is essential for high-quality aperture synthesis mapping.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006