Vega 1 Magnetic Field Data (0.1 s), Halley Comet

Magnetic field and position data are in the cometocentric solar ecliptic (CSE) coordinate system. CSE coordinate system for the spacecraft position:

• Origin is at comet position, x-axis from comet to the Sun, z-axis to ecliptic northpole.
• The (x,y)-plane is parallel to the ecliptic plane. CSE coordinate system for the magnetic field data:
• Axes are parallel to the CSE system for the position.
• This coordinate system is valid only for very short time, about 4 hours around the closest approach of the spacecraft to the comet, since for a larger angular distance of the spacecraft from the comet, the direction to the Sun from both objects will be different.