Calculation to Convert from Equatorial to Heliocentric coordinate systems Can anyone help me with the formulas to convert Equatorial coordinates (Right Ascension / Declination) into Heliocentric coordinates (Angle and Distance in relation to the Sun) ?
i.e. Ra/Dec of 6.7659/18.4563 ---&gt; 281.98 degrees and 0.4562 AUs
It feels like this is possible with no other inputs, but I can't figure it out.
No, this is not possible. Equatorial coordinates only specify the direction of a certain point in space (as seen from Earth), not the distance. During a solar eclipse, the Moon and the Sun have (approximately) the same equatorial coordinates, but the distance to the Sun is 0 or almost 1 AU.
It is possible to define equatorial or ecliptic coordinates with the Sun as center, but even then there is no general formula. You'll need the full position (i.e. three coordinates) of the Earth (relative to the Sun) or vice versa, and the full position of the object under observation to be able to convert the coordinates.