how close to plants can I get with 600 watt hps without burning?

I have a batwing style reflector 600w hps, and am wondering how close I can get the light to the plants. Anyone else that have this setup? I have a 12" oscillating fan blowing over the plants to keep them cool. Right now I have the light at 24", but am wondering if anyone else has had success with 8-12"?

Honestly I think it works 10x better having the fan blowing directly on the bulb to keep it cool. This works better than having the fan blowing over top of the plants. Having the fan blowing over top of your plants doesn't keep the temp down, having the fan blowing on the bulb will keep the temp down and let you put your plants really close. Both would be best, though.

ok, cool. I'll try that. I would like to get them down to 8-12", but it's pretty hot under there. Luckily the batwing gets rid of heat pretty well, so I'll hope for the best. Anyone else have any experience with the 600w hps???

just do the hand test..... put ur hand on top of the plants and if ur hand cant take the heat neither could ur plants