Heliocentric Julian Day Calculator

Although the speed of light is very fast, it is not infinite, and the incredible astronomical distances we are dealing with can lead to easily measurable timing effects due to light's finite speed. One such light time effect occurs because of the Earth's orbit around the Sun. Although the Earth's semi major axis is only 8.3 light minutes in size, this moving platform of an Earth can therefore be several light minutes closer to or further away from stars, especially those near the ecliptic. To account for this variation, astronomers recalculate Julian Days as if we were observing the star from the center of the Sun, i.e., a Heliocentric Julian Day. This is usually calculated by computer.

INPUTS UT Date (MM/DD/YYYY) / /         UT Time: : :         Object RA: h m s         DEC: ° ' ''        OUTPUTS