[Ross]

Firstly, welcome to the board. Glad to have you join.

I think you have pretty-much what you need to grow lots of genera of orchids. There's a lot more to it than light and humidity, but you have a great start. You might want to supplement the HPS light source with something "bluer" like high-output t5 florescent lights in 6500K spectrum or halide hot lamps. The temps sound fine for lots of orchids, and for the ones like Phalenopsis or Paphs that like it just a bit warmer at night, a plant propegation mat will supply gentle radiant heat to approx 15 degrees over the ambient air temp. So you would want to place it on its own timer to only run at night. Cool temps don't bother these plants until they have flower spikes, then they expect a bit warmer temps (like low 60s at night as the coolest). If you have specific questions regarding types of orchids, growing under lights, etc. visit the various forum sections and questions left under those sections are more likely to be answered by the experts. Once again, enjoy your stay here.