An Etymological Dictionary of Astronomy and Astrophysics

A geometric plane defined for the analysis/processing of → interferometer observations, for which the axes are conventionally termed u and v.

The plane is at right angles to a direction from which radiation is being received from the sky.

Unlike a typical telescope, a → radio interferometer cannot produce an image of the sky directly. Instead it measures the → Fourier transform of the sky brightness distribution in the uv plane. The Fourier transform relates the → interference pattern to the intensity on the sky. 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. Two telescopes form one baseline which represents one point in uv plane;

three telescopes create three baselines and are therefore represented by three points in uv plane.

Good uv coverage requires many simultaneous baselines amongst many antennas, or many sequential observations from a few antennas.

Good coverage of points is essential for high-quality

→ aperture synthesis mapping.

See also: u and v conventional symbols; → plane.

A geometric plane defined for the analysis/processing of → interferometer observations, for which the axes are conventionally termed u and v.

The plane is at right angles to a direction from which radiation is being received from the sky.

Unlike a typical telescope, a → radio interferometer cannot produce an image of the sky directly. Instead it measures the → Fourier transform of the sky brightness distribution in the uv plane. The Fourier transform relates the → interference pattern to the intensity on the sky. 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. Two telescopes form one baseline which represents one point in uv plane;

three telescopes create three baselines and are therefore represented by three points in uv plane.

Good uv coverage requires many simultaneous baselines amongst many antennas, or many sequential observations from a few antennas.

Good coverage of points is essential for high-quality

→ aperture synthesis mapping.

See also: u and v conventional symbols; → plane.

A four-color stellar → photometric system devised by B. Strömgren. It is based on measurements in the ultraviolet (3500 Å), violet (4100 Å), blue (4670 Å), and yellow (5470 Å) regions of the spectrum. The filters bandwidths are 340, 200, 160, and 240 Å respectively. Also known as Strömgren four-color photometry.

See also: u, v, b, and y referring to ultraviolet, violet, blue, and yellow
respectively; → system.

A four-color stellar → photometric system devised by B. Strömgren. It is based on measurements in the ultraviolet (3500 Å), violet (4100 Å), blue (4670 Å), and yellow (5470 Å) regions of the spectrum. The filters bandwidths are 340, 200, 160, and 240 Å respectively. Also known as Strömgren four-color photometry.

See also: u, v, b, and y referring to ultraviolet, violet, blue, and yellow
respectively; → system.