The Ohio Sky Survey was an

astronomical survey An astronomical survey is a general map or image of a region of the sky (or of the whole sky) that lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of images, spectra, or other observations of obje ...

of extragalactic radio sources. Data were taken between 1965 and 1971 using the

Big Ear The Ohio State University Radio Observatory was a Kraus-type (after its inventor John D. Kraus) radio telescope located on the grounds of the Perkins Observatory at Ohio Wesleyan University in Delaware, Ohio from 1963 to 1998. Known as Big Ear, th ...

radio telescope A radio telescope is a specialized antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Radio telescopes are the main observing instrument used in radio astronomy, which studies the radio frequency ...

at the

Ohio State University Radio Observatory The Ohio State University Radio Observatory was a Kraus-type (after its inventor John D. Kraus) radio telescope located on the grounds of the Perkins Observatory at Ohio Wesleyan University in Delaware, Ohio from 1963 to 1998. Known as Big Ear, th ...

(OSURO), also known as the "Big Ear Radio Observatory (BERO)". The survey covered 94% of the sky area between the limiting

declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the ...

s of 63°N and 36°S with a resolution at 1415 MHz of 40

arc minute A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The n ...

s in declination. The survey was carried out primarily at a frequency of 1415 MHz but observations were also made at 2650 MHz and 612 MHz. Roughly 19,620 sources were identified over the course of the survey of which 60% were previously uncatalogued. The survey was unique in that it covered a larger portion of the sky, to a greater depth, and at a higher frequency, than any previous survey. In addition, all previously catalogued sources were tabulated and maps of the areas surveyed were included with the positions of all catalogued sources. Sources discovered in the course of the survey were assigned names according to a coordinate numbering system consisting of a two-letter prefix followed by three digits. The first letter, O, stood for Ohio, and the second letter, B–Z inclusive (omitting O) indicated the source

right ascension Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point in question above the earth. When paired w ...

in hours (0–23 inclusive). The first digit indicated the declination zone in increments of 10°, while the last two digits give the source number within the specified region of right ascension and declination. Data reduction for the survey was done using a computer program developed by

John D. Kraus John Daniel Kraus (June 28, 1910 – July 18, 2004) was an American physicist known for his contributions to electromagnetics, radio astronomy, and antenna theory. His inventions included the helical antenna, the corner reflector antenna, a ...

and Robert S. Dixon. The Ohio Sky Survey was published in seven installments and two supplements.

References

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