Vernal Equinox - exact time?

Where can I find the EXACT time of the Vernal Equinox for 2003?

I’ve found several references to March 20, 8:00 PM EST. But all these seem to be rounded to the minute. I’ve seen others listing the time as early as 7:59 and as late as 8:06.

How about the second?

How can I know the source is reliable?

Thanks

The US Naval Observatory is the definitive source. They give the equinox as March 21 01:00, and that’s accurate to the nearest minute.

Since that’s 1:00 AM Universal Time (which is Greenwich Mean Time), to get to Eastern Standard Time, you subtract 5 hours, so the Equinox is March 20, 8:00 PM.

Happy Equinox!

Answered this question for my mom using the exact same resource earlier today.