Seasonal dependent on/off dusk/dawn triggering

[fred]

I'ld like an on/off dusk/dawn trigger that
varies with the the date so that if you
want it to come on at 20% light, it adds
the appropriate amount of time in the
winter and subtracts the appropriate amount
of time in the summer.  It would be very
much like the sine curve used to describe
the current dusk/dawn times but controlled
by percent dark/light at the user's
latitude rather than the minutes offset.

[bebop]

Absoutely agree with this idea although I'd
settle for 120-180 minute offsets for the
time being to accommodate the need for
lights to come on much before dusk due to
the lower angle of the sun etc. Then I'd
like to see a photo light sensor that could
be used to trigger a macro event based on
conditional factors. Haven't heard a peep
out of X10 about this request or the longer
offsets but I figure I'll just
keep "nagging" about it until I get some
sort of reaction from X10!