Fourth Cambridge Survey
Encyclopedia
The Fourth Cambridge Survey (4C) is an astronomical catalogue of celestial radio sources as measured at 178 MHz using the 4C Array
. It was published in two parts, in 1965 (for declination
s +20 to +40) and 1967 (declinations -7 to + 20 and +40 to +80), by the Radio Astronomy Group
of the University of Cambridge
. References to entries in this catalogue use the prefix 4C followed by the declination in degrees, followed by a period, and then followed by the source number on that declination strip, e.g. 4C-06.23.
The 4C Array, which used the technique of aperture synthesis
, could reliably position sources of less than 2 Jy
, to within about 0.35 arcmin in Right ascension
and 2.5 arcmin in declination
.
4C Array
The 4C Array is a cylindrical paraboloid radio telescope at the Mullard Radio Astronomy Observatory. It is similar in design to the Molonglo Observatory Synthesis Telescope. It is 450 m long, 20 m wide, with a second, moveable element...
. It was published in two parts, in 1965 (for declination
Declination
In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...
s +20 to +40) and 1967 (declinations -7 to + 20 and +40 to +80), by the Radio Astronomy Group
Cavendish Astrophysics Group
The Cavendish Astrophysics Group is based at the Cavendish Laboratory at the University of Cambridge. The group operates all of the telescopes at the Mullard Radio Astronomy Observatory except for the 32m MERLIN telescope, which is operated by Jodrell Bank.The group is the second largest of three...
of the University of Cambridge
University of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...
. References to entries in this catalogue use the prefix 4C followed by the declination in degrees, followed by a period, and then followed by the source number on that declination strip, e.g. 4C-06.23.
The 4C Array, which used the technique of aperture synthesis
Aperture synthesis
Aperture synthesis or synthesis imaging is a type of interferometry that mixes signals from a collection of telescopes to produce images having the same angular resolution as an instrument the size of the entire collection...
, could reliably position sources of less than 2 Jy
Jansky
The flux unit or jansky is a non-SI unit of spectral flux density equivalent to 10−26 watts per square metre per hertz...
, to within about 0.35 arcmin in Right ascension
Right ascension
Right ascension is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. The other coordinate is the declination.-Explanation:...
and 2.5 arcmin in declination
Declination
In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...
.
External links
- The Fourth Cambridge Survey on the internet.