Julian Day Conversion

Many astronomical observations require that the data be presented with Julian Dates. The following charts will display the Julian Date of the first of each month for this and the coming year.

Add 2,400,000 to get the full Julian Day. So, the full Julian Day for July 1st 2016 is 2457570. The Julian Day is a consecutive day count starting on January 1 of the year -4712 (= 4713 B.C.E.).

Julian Days (JD) for 2016:

Add the day of the month to the number shown. Julian Days begin at Greenwich Noon.

January

57387

July

57569

February

57418

August

57600

March

57447

September

57631

April

57478

October

57661

May

57508

November

57692

June

57539

December

57753

Julian Days (JD) for 2017:

Add the day of the month to the number shown. Julian Days begin at Greenwich Noon.

January

57784

July

57965

February

57815

August

57996

March

57843

September

58027

April

57874

October

58057

May

57904

November

58088

June

57935

December

58118

An Easier Way to Calculate JD:

Though you can calculate the JD yourself, we highly recommend you go to the AAVSO site for a direct conversion to Julian Date and decimal. There is an app that allows you to enter the data in either form and convert it. Also, you can find a thorough explanation about Julian Dates and why they are so important..