How do I set it and can I use it indoors? - Intermatic Outdoor Timer/Photo Control HB51RC

I see nothing in the manual that says 'outdoor use only' EXCEPT timer runs on photoelectric eye.
Timer turns ON automatically at dusk, so if timer is inside, and indoor lights are ON, then timer stays OFF.

http://www.intermatic.com/~/media/files/intermatic/products/instructions/timers/hb51rc%20-%20english.ashx

http://www.intermatic.com/products/timers/consumer%20outdoor%20timers/electromechanical%20timers/hb51rc.aspx


To use timer outdoors.
Plug timer into wall.
Timer turns ON automaically at Dusk.
Rotate dial to set how long timer will stay ON.
Set timer to turn OFF 2 4 6 8 Hours after dusk
Set timer to turn off at dawn
Set timer to ON so lights are ON full time
Set timer to OFF so lights are off full time.