Rick Measham schreef:
> Sorry, I should have said that I wasn't interested in the historical 
> context for this, only in the mathmatics behind it. I realised that 
> historically they wouldn't have done what I was suggesting, but as 
> you say, for us computer owning people it would be nice.

In that case, I would use a function like:

  fOurTime = fGreekTime + .5 * (fNight - .5) * sin( fGreekTime * 2 * pi )

where
fOurTime = fractional time (0 = midnight, 0.25 = 6AM, ..., 1 = midnight)
fNight = length of night as fraction of 24h.
pi = 3.1
fGreekTime = fractional Greek time.

At dawn, it's 6AM Greek time = 0.25; the sine is 1; so fUTC = 0.25 +
.5*fNight - .25 = half a night length after midnight (in standard
hours), = dawn.

Eugene

Reply via email to