1000 Watt get it innn

How close can a 1000 watt hps be to the canopy??? quick answers thanks

I run a 1000 in a 4x4 area- I usually stay 20" away, roughly (they like it rough). If you're too close they either burn and stunt or "run" out , thin and airy. Sometimes I like them more like 30-36 to get good spread from the light. I don't always shoot for close if the plants are thriving, and I try to move them around regularly to keep it fair.