On 5 Jul, 08:46, Dennis Lee Bieber <[EMAIL PROTECTED]> wrote: > On Wed, 04 Jul 2007 22:12:46 -0400, Roy Smith <[EMAIL PROTECTED]> declaimed > the following in comp.lang.python: > > > Astronomers use Julian Date (http://en.wikipedia.org/wiki/Julian_date) for > > calculations like this. It's a widely used format and highly portable. > > I'm sure there are libraries to deal with it in all the languages you > > mention (and more). Ask on sci.astro for more information. > > <playing devils advocate> But do you also need to account for > Besselian or Julian centuries (Astronomy used to use B1900 as a > computational epoch, but now uses J2000. A Julian century is 36525 days, > Besselian century was 36524.22 days.
Whew! It was for reasons such as this that I suggested treating a day (i.e. a /nominal/ 24-hour period) as the primary unit. The Gregorian switch to Julian, for example, missed out a bunch of days to adjust the calendars of Christendom but they had to be whole numbers of days. In terms of real people (about the level I need) once a dividing line has been chosen between one day and the next it becomes a reference point. Incidentally I have chosen to store /average/ values in the application so if the sample period is 10 seconds and the count increases by 45 I will store 4.5. This is plottable directly and I could even allow an 11 second sample when a leap second is added (if I needed that detail). Is your Julian century a bit long, on average, 2000, 2400, 2800 etc having 28 days in Feb? -- http://mail.python.org/mailman/listinfo/python-list
