epoch Prime

[salvomic]

(01-05-2018 07:51 PM)Dieter Wrote:  However, I don't know if the line that checks whether a date is before or after 15 Oct 1582 (switch from Julian to Gregorian calendar) is correct. But this can be omitted anyway since in 1582 there was no Unix. At least as far as I know. ;-)

No, I think there was no Unix in 1582

Quote:... You do not have to do this manually. IIRC since 2015 the Prime includes the required commands, e.g. DDAYS and DATEADD. Take a look at the manual.

yes, I know those functions, definitely, and I suggested to use them to make the program...

as far as the MAKELIST and "lista", the list is intended so:
• with listnow() we get the time now, i.e. {2018,1,5.87368055555} where the fraction .8736 is the time in /24
• so julianday({2018,1,5.87368055555}) or julianday(listnow) returns 2458124.37368, the Julian Date.

Other astronomical date functions in Effemeridi and Astrolab 4 app ...

EDIT: following your idea to use Julian Day, I tried this:
• julianday({1970,1,1}) -> 2440587.5
• julianday(listnow) -> 2458124.38559 :: in the same time I started the Bill's program (EPOCH) on my HP-41CX, calculated for my time zone (+1h) with 3600 in 00 register and it returned epoch = 1515183311
• (2458124.38559-2440587.5) (julianday now - Julianday 1970 Jan 1), that is 17536.8559 days
• 86400*17536.8559 returns 1515186914.98
last result is 3603.98 secs greater that EPOCH program: something went wrong: about 1 hour, and this should be the GMT difference.

So we should assemble these data to get epoch, but perhaps there is a way more concise to get it...