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salvomic · (This post was last modified: 01-05-2018 09:25 PM by salvomic.)

(01-05-2018 08:47 PM)Dieter Wrote: Please note that the Julian day number as it is used in astronomy refers to noon (12:00) for integer values, not midnight.

Definitely

(01-05-2018 08:47 PM)Dieter Wrote: But why don't you simply try DDAYS(1970.0101, 2018.0105) to get the number of days since then (=17536), multiply this by 86400 (=1515110400) and finally add the seconds of the current time (3600*hours + 60*minutes + seconds)? It's really as simple as that. ;-)

Right.
Then we can use the variables Date and Time from the Prime (Vars catalog, or to write them with the first uppercase), so:

Code:

86400*(DDAYS(1970.0101,Date))+3600*HMS➝(Time)

is the same as

Code:

86400*(julianday(listnow)-2440587.5)

That's epoch(), right?
However the result returned is about +3600 secs from the result of Bill's EPOCH calculated for UTC+1 (3600 in 00)...
Subtracting 3600 we get the Epoc for GMT.

(01-05-2018 08:47 PM)Dieter Wrote: Maybe this difference of 4 s is related to leap seconds between 1970 and today? But no... this should be more than just four.

or maybe simply the difference in the execution time between HP41CX (a bit more slow) and the Prime...