About this tool
Should lights come on at sunset or dusk?
Civil dusk, about 25 to 30 minutes after sunset, is when the sky is dark enough for landscape lighting to read. Switching on at sunset wastes a little energy but looks fine too.
What is an astronomic timer?
A timer that knows your latitude and the date, so it tracks sunset through the year and adjusts for daylight saving automatically. No seasonal resets.
Photocell or timer?
A photocell turns lights on at dusk and off at dawn. A timer or smart controller can also turn them off at a set hour. Many Austin Landscape Lighting systems use a photocell for on and a timer for off.