Alright, I'm new to the forum, and I've got to say, it is quite impressive. Okay, my question: How do I convert radiant power (uW/10nm/Lumens) to W/m^2? I am conducting a simulated solar radiation test. I need to know the spectral power distribution of a certain metal hallide bulb. The manufacturer provided a chart of radiant power/wavelength. The standard I'm testing to (MIL-STD-810F) has tolerance bands in the UV, VIS, and IR that the bulb must conform to. The values given are in W/m^2. I have an eppley pyranometer, but it measures irradiance across the whole spectrum, I do not have filters available at this time. I'm sure theres got to be some formula for this. I have not taken calc yet, but have support from several engineers here as far as the math goes. Any help would be appreciated. Thanks!