Airy-0 is a crater inside the larger Airy Crater on

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

, whose location historically defined the Martian

prime meridian A prime meridian is an arbitrarily chosen meridian (geography), meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. On a spheroid, a prime meridian and its anti-meridian (the 180th meridian ...

. It is about 0.5 km (0.3 mile) across and lies within the dark region Sinus Meridiani, one of the early albedo features to be identified on Mars. In 2018, the

IAU The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

Working Group on Cartographic Coordinates and Rotational Elements recommended setting the longitude of the Viking 1 lander (47.95137° west) as the reference line. This definition maintains the position of the center of Airy-0 at 0° longitude, within the tolerance of current cartographic uncertainties. Merton Davies tied this crater into an extensive

geodetic control network A geodetic control network is a network, often of triangles, that are measured precisely by techniques of ''control surveying'', such as terrestrial surveying or satellite geodesy. It is also known as a geodetic network, reference network, contro ...

of the planet Mars based on

Mariner 9 Mariner 9 (Mariner Mars '71 / Mariner-I) was a robotic spacecraft that contributed greatly to the exploration of Mars and was part of the NASA Mariner program. Mariner 9 was launched toward Mars on May 30, 1971, from Spaceport Florida Launch Comp ...

and earlier photographs. The Mariner 9 Geodesy/Cartography Group proposed that the prime meridian of Mars be defined by the center of Airy-0, which was selected by Harold Masursky, Gerard de Vaucouleurs, and Merton Davies at a Group meeting on 14 August 1972. It was named in honor of the British

Astronomer Royal Astronomer Royal is a senior post in the Royal Households of the United Kingdom. There are two officers, the senior being the astronomer royal dating from 22 June 1675; the junior is the astronomer royal for Scotland dating from 1834. The Astro ...

Sir

George Biddell Airy Sir George Biddell Airy (; 27 July 18012 January 1892) was an English mathematician and astronomer, as well as the Lucasian Professor of Mathematics from 1826 to 1828 and the seventh Astronomer Royal from 1835 to 1881. His many achievements inc ...

(1801–1892), who in 1850 built the transit circle telescope at

Greenwich Greenwich ( , , ) is an List of areas of London, area in south-east London, England, within the Ceremonial counties of England, ceremonial county of Greater London, east-south-east of Charing Cross. Greenwich is notable for its maritime hi ...

. The location of that telescope was subsequently chosen to define the location of Earth's prime meridian. Meridianicropped

Notes

References

External links

View of Airy-0 at Google Mars
* {{Portal bar, Solar System Impact craters on Mars Margaritifer Sinus quadrangle Prime meridians Sinus Sabaeus quadrangle