[mh] Timing events

[Dave S. <da...@st...>]

What should the syntax be for triggering an event at an offset from 
$Time_Sunrise, for instance?  Like if I have a light that I want turned 
off at 10 minutes after sunrise, or turned on 10 minutes before sunset?  
I've got down how to do things at sunrise, sunset, etc., but not how to 
do this.
Thanks!
-Dave