The

Uppsala Uppsala ( ; ; archaically spelled ''Upsala'') is the capital of Uppsala County and the List of urban areas in Sweden by population, fourth-largest city in Sweden, after Stockholm, Gothenburg, and Malmö. It had 177,074 inhabitants in 2019. Loc ...

General Catalogue of Galaxies (UGC) is a catalogue of 12,921

galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar Sys ...

visible from the northern hemisphere. It was first published in 1973. A slashing smudge across the sky

The catalogue includes essentially all galaxies north of

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. The declination angle is measured north (positive) or ...

−02°30′ and to a limiting diameter of 1.0

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

or to a limiting

apparent magnitude Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), ...

of 14.5. The primary source of data is the blue prints of the Palomar Observatory Sky Survey (POSS). It also includes galaxies smaller than 1.0

in diameter but brighter than 14.5 magnitude from the Catalogue of Galaxies and of Clusters of Galaxies (CGCG). The catalogue contains descriptions of the galaxies and their surrounding areas, plus conventional system classifications and position angles for flattened galaxies. Galaxy diameters are included and the classifications and descriptions are given in such a way as to provide as accurate an account as possible of the appearance of the galaxies on the prints. The accuracy of coordinates is only what is necessary for identifications purposes. The catalogue was edited by Peter Nilson, at the time Doctor of Astronomy and a researcher at Uppsala, who had already published some essays about the history of his science; a couple of years later he left his career as a professional astronomer behind and became a full-time writer, novelist and essayist, although the relationship of humans to space and cosmology, and the history of science, remained powerful themes in his later writing.

Addendum

There is an addendum to the catalogue called Uppsala General Catalogue Addendum, which is abbreviated as UGCA.

References

External links

UGC - Uppsala General Catalog of Galaxies
{{Portal bar, Astronomy, Stars, Outer space Astronomical catalogues of galaxies * 1973 documents 1973 in science

Addendum

See also

References

External links