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Carrington 
A coordinate system which is centered at the Sun and is "fixed" with respect to the synodic rotation rate; the mean synodic value is about 27.2753 days. The Astronomical Almanac gives a value for Carrington longitude of 349.03 degrees at 0000 UT on 1 January 1995. 

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CGM 
Corrected Geomagnetic  A coordinate system from a spatial point with GEO radial distance and geomagnetic latitude and longitude, follow the epochappropriate IGRF/DGRF model field vector through to the point where the field line crosses the geomagnetic dipole equatorial plane. Then trace the dipole magnetic field vector Earthward from that point on the equatorial plane, in the same hemisphere as the original point, until the initial radial distance is reached. Designate the dipole latitude and longitude at that point as the CGM latitude and longitude of the original point. See <http://nssdc.gsfc.nasa.gov/space/cgm/cgmm_des.html> 

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CSO 
Corrected Solar Orbital  A coordinate system related to Earth where X is antisunward, Y along the orbital velocity direction. 

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DM 
Dipole Meridian  A coordinate system centered at the observation point. Z axis is parallel to the Earths dipole axis, positive northward. X is in the plane defined by Z and the line linking the observation point with the Earths center. Y is positive eastward. See <http://cdpp.cnes.fr/00428.pdf> 

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ECD 
Eccentric Dipole (ECD) coordinate system that aligns with a dipole whose origin and orientation may be different from the physical center and spin axis of the containing body. The IGRF12 coefficients for 2015 are used to determine the origin for the earth. The 2015 positions are North dip pole: latitude: 86.29, longitude 160.06. South dip pole latitide: 64.28, longitude: 136.59, North geometric pole latitude: 80.37, longitude: 72.63, South geomagnetic pole latitude: 80.37, longitude: 107.37ECD is defined in doi:10.1186/s4062301502289. 

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ECEF 
The EarthCentered, EarthFixed (ECEF) coordinate system has point (0,0,0) defined as the center of mass of the Earth. Its axes are aligned with the International Reference Pole (IRP) and International Reference Meridian (IRM). The xaxis intersects the sphere of the Earth at 0 degree latitude (Equator) and 0 degree longitude (Greenwich). The zaxis points north. The yaxis completes the right handed coordinate system. 

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ENP 
ENP (also called PEN)  The P vector component points northward, perpendicular to orbit plane which for a zero degree inclination orbit is parallel to Earths spin axis. The E vector component is perpendicular to P and N and points earthward. The N component is perpendicular to P and E and is positive eastward. 

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GEI 
GEI Geocentric Equatorial Inertial  A coordinate system where the Z axis is along Earths spin vector, positive northward. X axis points towards the first point of Aries (from the Earth towards the Sun at the vernal equinox). See Russell, 1971. When the X axis is the direction of the mean vernal equinox of J2000, the coordinate system is also called GCI. Then the Z axis is also defined as being normal to the mean Earth equator of J2000. 

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GEO 
Geographic  geocentric corotating  A coordinate system where the Z axis is along Earths spin vector, positive northward. X axis lies in Greenwich meridian, positive towards Greenwich. See Russell, 1971. 

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GPHIO 
Kronian Solar Orbital  A coordinate system related to Saturn where X is antisunward, Y along the orbital velocity direction. 

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GSE 
Geocentric Solar Ecliptic  A coordinate system where the X axis is from Earth to Sun. Z axis is normal to the ecliptic, positive northward. See Russell, 1971. 

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GSEQ 
Geocentric Solar Equatorial  A coordinate system where the X axis is from Earth to Sun. Y axis is parallel to solar equatorial plane. Z axis is positive northward. See Russell, 1971 

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GSM 
Geocentric Solar Magnetospheric  A coordinate system where the X axis is from Earth to Sun, Z axis is northward in a plane containing the X axis and the geomagnetic dipole axis. See Russell, 1971 

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HAE 
Heliocentric Aries Ecliptic  A coordinate system where the Z axis is normal to the ecliptic plane, positive northward. X axis is positive towards the first point of Aries (from Earth to Sun at vernal equinox). Same as SE below. See Hapgood, 1992. 

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HCC 
Heliocentric Cartesian  A 3D orthonormal coordinate system that is primarily intended to specify with two dimensions a point on the solar disk. The Z axis points toward the observer. The Y axis lies in the plane defined by the solar spin vector and the Z axis, positive northward. The X axis is perpendicular to the Y and Z axes, positive toward solar west. Standard representation for this system is via the points x and y values, expressed either as physical distances or as fractions of the solar disk radius. 

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HCI 
Heliographic Carrington Inertial. 

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HCR 
Heliocentric Radial  A 3D orthonormal coordinate system that is primarily intended to specify with two dimensions a point on the solar disk. The Z axis points toward the observer. The Y axis lies in the plane defined by the solar spin vector and the Z axis, positive northward. The X axis is perpendicular to the Y and Z axes, positive toward solar west. Standard representation for this system is via the points distance rho from the Z axis [Rho = SQRT(x**2 + y**2)] and its phase angle psi measured counterclockwise from the +Y axis [psi = arctan (y/x)] 

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HEE 
Heliocentric Earth Ecliptic  A coordinate system where the Z axis is normal to the ecliptic plane, positive northward. X axis points from Sun to Earth. See Hapgood, 1992 

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HEEQ 
Heliocentric Earth Equatorial  A coordinate system where the Z axis is normal to the solar equatorial plane, positive northward. X axis is generally Earthward in the plane defined by the Z axis and the SunEarth direction. See Hapgood, 1992. 

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HERTN 
HelioEclipitic Radial Tangential Normal coordinate system. Typically centered at a spacecraft. The X axis (radial) is set as the primary axis, and is defined as the axis pointing from the spacecraft to the Sun. The Z axis (tangential) is set as the secondary axis, and is defined as that portion of the ecliptic rotational axis which is perpendicular to the primary axis. The Y axis (Normal) is defined as Z cross X. 

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HG 
Heliographic  A heliocentric rotating coordinate system where the Z axis is normal to the solar equatorial plane, positive northward. X, Y axes rotate with a 25.38 day period. The zero longitude (X axis) is defined as the longitude that passed through the ascending node of the solar equator on the ecliptic plane on 1 January, 1854 at 12 UT. See <http://nssdc.gsfc.nasa.gov/space/helios/coor_des.html> 

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HGI 
Heliographic Inertial  A heliocentric coordinate system where the Z axis is normal to the solar equatorial plane, positive northward. X axis is along the intersection line between solar equatorial and ecliptic planes. The X axis was positive at SE longitude of 74.367 deg on Jan 1, 1900. (See SE below.) See <http://nssdc.gsfc.nasa.gov/space/helios/coor_des.html> 

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HGRTN 
Heliocentric Radial Tangential Normal coordinate system (aka RTN). Typically centered at a spacecraft. Used for IMF and plasma V vectors. The X axis (radial) is set as the primary axis, and is defined as the axis pointing from the spacecraft to the Sun. The Z axis (tangential) is set as the secondary axis, and is defined as that portion of the solar North rotational axis which is perpendicular to the primary axis. The Y axis (normal) is defined as Z cross X. 

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HPC 
Helioprojective Cartesian = A 3D orthonormal (lefthanded) coordinate system that is primarily intended to specify with two dimensions a point on the solar disk. The Z axis points from the observer to the center of the solar disk. The Y axis lies in the plane defined by the solar spin vector and the Z axis, positive northward. The X axis is perpendicular to the Y and Z axes, positive toward solar west. Given as the distance between the observer and the center of the solar disk, the standard representation of an (x,y) point on the solar disk is via the points longitude angle [arctan (x/d)] and latitude angle [arctan y/d]. 

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HPR 
Helioprojective Radial  A 3D orthonormal (lefthanded) coordinate system that is primarily intended to specify with two dimensions a point on the solar disk. The Z axis points from the observer to the center of the solar disk. The Y axis lies in the plane defined by the solar spin vector and the Z axis, positive northward. The X axis is perpendicular to the Y and Z axes, positive toward solar west. Given as the distance between the observer and the center of the solar disk, the standard representation for this system of an (x,y) point on the solar disk is via the points latitude angle theta {= arctan [SQRT(x**2 + y**2)]/d]} or equivalent declination parameter delta (= theta  90 deg), and its phase angle psi as measured counter clockwise from the +Y axis [psi = arctan (y/x)]. 

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HSM 
Heliospheric Solar Magnetospheric  A coordinate system where the X axis is from Earth to Sun, Z axis is northward in a plane containing the X axis and the geomagnetic dipole axis. 

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J2000 
An astronomical coordinate system which uses the mean equator and equinox of Julian date 2451545.0 TT (Terrestrial Time), or January 1, 2000, noon TT. (aka J2000) to define a celestial reference frame. 

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JSM 
Jovian Solar Magnetospheric  A coordinate system related to Jupiter where the X axis is from Jupiter to Sun, Z axis is northward in a plane containing the X axis and the Jovian dipole axis. 

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JSO 
Jovian Solar Orbital  A coordinate system related to Jupiter where X antisunward, Y along the orbital velocity direction. 

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KSM 
Kronian Solar Magnetospheric  A coordinate system related to Saturn where the X axis is antisunward, Z axis is northward in a plane containing the X axis and the Kronian dipole axis. 

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KSO 
Kronian Solar Orbital  A coordinate system related to Saturn where X is antisunward, Y along the orbital velocity direction. 

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LGM 
Local Geomagnetic  A coordinate system used mainly for Earth surface or near Earth surface magnetic field data. X axis northward from observation point in a geographic meridian. Z axis downward towards Earths center. In this system, H (total horizontal component) = SQRT (Bx^2 + By^2) and D (declination angle) = arctan (By/Bx) 

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MAG 
Geomagnetic  geocentric. Z axis is parallel to the geomagnetic dipole axis, positive north. X is in the plane defined by the Z axis and the Earths rotation axis. If N is a unit vector from the Earths center to the north geographic pole, the signs of the X and Y axes are given by Y = N x Z, X = Y x Z.. See Russell, 1971, and <http://cdpp.cnes.fr/00428.pdf> 

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MFA 
Magnetic Field Aligned  A coordinate system spacecraftcentered system with Z in the direction of the ambient magnetic field vector. X is in the plane defined by Z and the spacecraftSun line, positive sunward. See <http://cdpp.cnes.fr/00428.pdf> 

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MSO 
Mars/Mercury Solar Orbital A coordinate system related to Mars or Mercury. A coordinate system where, depending on the body (Mars or Mercury), X is antisunward, Y along the orbital velocity direction. 

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RTN 
Radial Tangential Normal. Typically centered at a spacecraft. Used for IMF and plasma V vectors. The X axis (radial) is set as the primary axis, and is defined as the axis pointing from the spacecraft to the Sun. The Z axis (tangential) is set as the secondary axis, and is defined as that portion of the solar North rotational axis which is perpendicular to the primary axis. The Y axis (normal) is defined as Z cross X. 

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SC 
Spacecraft  A coordinate system defined by the spacecraft geometry and/or spin. Often has Z axis parallel to spacecraft spin vector. X and Y axes may or may not corotate with the spacecraft. See SR and SR2 below. 

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SE 
Solar Ecliptic  A heliocentric coordinate system where the Z axis is normal to the ecliptic plane, positive northward. X axis is positive towards the first point of Aries (from Earth to Sun at vernal equinox). Same as HAE above. See <http://nssdc.gsfc.nasa.gov/space/helios/coor_des.html> 

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SM 
Solar Magnetic  A geocentric coordinate system where the Z axis is northward along Earths dipole axis, X axis is in plane of z axis and EarthSun line, positive sunward. See Russell, 1971. 

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SpacecraftOrbitPlane 
A coordinate system where X lies in the plane normal to and in the direction of motion of the spacecraft, Z is normal to this plane and Y completes the triad in a righthanded coordinate system. 

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SR 
Spin Reference  A special case of a Spacecraft (SC) coordinate system for a spinning spacecraft. Z is parallel to the spacecraft spin vector. X and Y rotate with the spacecraft. See <http://cdpp.cnes.fr/00428.pdf> 

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SR2 
Spin Reference 2  A special case of a Spacecraft (SC) coordinate system for a spinning spacecraft. Z is parallel to the spacecraft spin vector. X is in the plane defined by Z and the spacecraftSun line, positive sunward. See <http://cdpp.cnes.fr/00428.pdf> 

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SSE 
Spacecraft Solar Ecliptic  A coordinate system used for deep space spacecraft, for example Helios.  X axis from spacecraft to Sun. Z axis normal to ecliptic plane, positive northward. Note: Angle between normals to ecliptic and to Helios orbit plane ~ 0.25 deg. 

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SSE_L 
Selenocentric Solar Ecliptic. The X axis points from the center of the Earths moon to the sun, the Z axis is normal to the ecliptic plane, positive northward. And the Y axis completes the righthanded set of axes. 

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TIIS 
Kronian Solar Orbital  A coordinate system related to Saturn where X is antisunward, Y along the orbital velocity direction. 

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VSO 
Venus Solar Orbital  A coordinate system related to Venus where X is antisunward, Y along the orbital velocity direction. 

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WGS84 
The World Geodetic System (WGS) defines a reference frame for the earth, for use in geodesy and navigation. The WGS84 uses the zero meridian as defined by the Bureau International de lHeure. 
