How to Interpret the Observation Date Format from the Minor Planet Center (MPC)

-- Anura Guruge | June 6, 2020


Can you please help me decode ‘decimal’ time as used by the MPC etc. What I mean is: 2020-05-27.54100.

I am fine till I get to the decimal point. Then I am lost & baffled & worse still just can’t find a link on Google that will explain it to I.

Please help. Just send me a link or two. I am good at reading. Thanks. SMILE.

-- Anura Guruge


I believe that the observation date format which includes a decimal on the day value indicates fractions of a day.  For example in the date 2020-05-27.54100, the part past the decimal is interpreted as 0.54100*24 hours = 12.984 hours = 12 hours and 0.984*60 minutes = 12 hours 59.04 minutes = 12 hours 59 minutes 0.04*60 seconds = 12 hours 59 minutes 2.4 seconds.  Therefore, your example date would be 12 hours 59 minutes 2.4 seconds on May 27 2020.

-- Jeff Mangum