Modified Julian Day

> Not being much of a GPS expert, I know little about Julian dates. Could someone confirm for me that January 1, 2012 would be Julian Day 55927?

JD 2455927.500000

I use http://www.usno.navy.mil/

Home ? USNO ? Astronomical Applications ? Data Services

A lot of other cool things there.

Thanks Tim! I wonder if the "modified" Julian Day refers to the rounding and the first two digits being removed.

You might want to check this out:

http://en.wikipedia.org/wiki/Julian_day

“The Modified Julian Day is found by rounding downward. The MJD was introduced by the Smithsonian Astrophysical Observatory in 1957 to record the orbit of Sputnik via an IBM 704 (36-bit machine) and using only 18 bits until August 7, 2576. MJD is the epoch of OpenVMS, using 63-bit date/time postponing the next Y2K campaign to July 31, 31086 02:48:05.47.[7]”

Loyal

There seems to be a little confusion as to Julian dates, years ago, a TGO trainer referred to the day of the year as the Julian date. I informed him that the Julian date was a much bigger number.

I do beleive that it's Julian Day 1.
Julian Date.....something else.