Search results
Results from the WOW.Com Content Network
Galactic longitude (l) is measured with primary direction from the Sun to the center of the galaxy in the galactic plane, while the galactic latitude (b) measures the angle of the object above the galactic plane. Longitude (symbol l) measures the angular distance of an object eastward along the galactic equator from the Galactic Center ...
The cosine of a latitude (declination, ecliptic and Galactic latitude, and altitude) are never negative by definition, since the latitude varies between −90° and +90°. Inverse trigonometric functions arcsine, arccosine and arctangent are quadrant-ambiguous, and results should be carefully evaluated.
The supergalactic coordinate system is a spherical coordinate system in which the equator lies in the supergalactic plane.. By convention, supergalactic latitude is usually abbreviated SGB, and supergalactic longitude as SGL, by analogy to b and l conventionally used for galactic coordinates.
In 1958 the International Astronomical Union (IAU) decided to adopt the position of Sagittarius A as the true zero coordinate point for the system of galactic latitude and longitude. [11] In the equatorial coordinate system the location is: RA 17 h 45 m 40.04 s, Dec −29° 00′ 28.1″ (J2000 epoch).
The zero of longitude of galactic coordinates was also defined in 1959 to be at position angle 123° from the north celestial pole. Thus the zero longitude point on the galactic equator was at 17 h 42 m 26.603 s , −28° 55′ 00.445″ (B1950) or 17 h 45 m 37.224 s , −28° 56′ 10.23″ (J2000), and its J2000 position angle is 122.932°.
Quadrants are described using ordinals—for example, "1st galactic quadrant", [1] "second galactic quadrant", [2] or "third quadrant of the Galaxy". [3] Viewing from the north galactic pole with 0 degrees (°) as the ray that runs starting from the Sun and through the galactic center, the quadrants are as follows (where l is galactic longitude):
Ecliptic longitude Ecliptic longitude or celestial longitude (symbols: heliocentric l, geocentric λ) measures the angular distance of an object along the ecliptic from the primary direction. Like right ascension in the equatorial coordinate system, the primary direction (0° ecliptic longitude) points from the Earth towards the Sun at the ...
Galactic coordinates could use the Galactic North and South Poles as the references for Galactic Latitude, and the Andromeda Galaxy as the zero of Galactic Longitude. These would be stable for at least 35 million years, probably throughout the entire 220 million year orbit of the solar system around the Milky Way.