[time-nuts] More 60 Hz data/graphs

Tom Van Baak tvb at LeapSecond.com
Mon Jul 4 05:28:36 UTC 2011


> Hal,
> 
> That's good stuff. Sadly, I've got to convert UTC to your local time to
> interpret the results, so I haven't done it. Tom's MJD will be even worse.

Bill,

If you know C, see mjd_code.c under www.leapsecond.com/tools/.

Otherwise, if you use Excel it's even easier -- just subtract the
magic number 15018 from a MJD value and you get date/time
in Excel format.

Dealing with timezones is easy too; subtract the fraction N/24
where N is 4,5,6,7,8 here in the US. But let's keep everything
in UTC since the grid crosses timezones (doesn't it?).

A note about:

#define MJD_TO_EXCEL(n) ( (n) - 15018 )

The reason this works is that MJD has an origin of 17-Nov-1858
and Excel uses an origin of (well, sort of) 0-Jan-1900. There are
15,018 days between those time-scales.

/tvb




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