Moon Calculator | Julian Date Converter

Date and time are expressed at the Prime Meridian, Greenwich, England, using a 24-hour clock. Your local date and time depends on your time zone offset (+/- hrs.).

Date Field: Enter a date and time. Then "submit Date" to see the Julian Day Number. Gregorian dates are used after 1582 and Julian dates before 1582.

Julian Day Field: Enter a whole or fractional Julian Day Number greater than 808299 and less than 2634167. Then "Submit aJDN." Enter a lattitude (negative south of equator) and longitude (negative west of Greenwich).

Add or subtract days by entering a whole or decimal number of days. Place a minus symbol in front of the number of days to subtract. Enter a zero stop adding.

The small white dot near Earth in our illustration is a lunar apside (perigee or apogee). The red dot is a node of the ecliptic (ascending or descending). When a new or full moon is at or is opposite to the red dot, an eclipse occurs. For example, a very famous eclipse occurred over Nineveh in Jonah's time, 763 B.C. To see how the red dot is displayed, enter the following JD Number in the form above: 1442903.089 , or click Nineveh Bur-Sagale eclipse. The sun, earth, moon, and nodes (red dot) are all in line.

The blue-green dot opposite the earth indicates the constellation. | A 24-hour clock simply adds twelve hours after noon time. For example 2:00 p.m is the same as 14:0:0 (2+12). 10 O'clock p.m. is 22:00 (10+12) and so on.