Mark Campanelli

I need to review this discussion further, but here is my open source implementation of this: https://github.com/markcampanelli/pvfit/tree/master/pvfit/measurement#pvfitmeasurementspectral_correction

Here are a couple relevant articles regarding spectral corrections, and my code aimed to accommodate both traditional and newer use cases for spectral corrections. My colleague Behrang Hamadani at NIST...

IIRC, the issue between the IEC and ASTM standards had to due with the "tail" of the spectral irradiance past 4 microns. In IEC, the tail function was not provided,...

@adriesse I have just started to take a look at this. I hit some snags trying to pull the branch, but I think that's on my end. Hopefully I'll have...

@adriesse I added a new comment under the resolved comment for the usable fraction calculations that may not show up as new for you.

Using the example data for the spectral radiance of the sun and the spectral responsivity of a Si reference device, the error in the SMM when truncating both integrals appears...

@adriesse Would it be possible to include an example in this PR of how this code is used for a specific use case or cases? If I were to try...

I was playing around with a project structure like this: ``` pvlib-python/ data/ weather/ atmosphere_gold.csv atmosphere_gold.json atmosphere_gold.py (generates the gold files) ... dc_device_iv/ lfm/ (loss factor model) sapm/ sdm/ desoto/...

Thanks for clarifying @cwhanse. I would say that the online PVsyst documentation is misleading. Would you/anyone be opposed to factoring out the R_sh calculation into a separately accessible function?

As an aside, I wonder if a simple 2-parameter model such as ```python def R_sh_at_G(*, G, R_sh_zero, R_sh_ref, G_ref=1000.): return R_sh_zero * (R_sh_ref / R_sh_zero)**(G/G_ref) ``` would have sufficed?