What does "wid" stand for?

[kurt-rhee]

Hey @kevinsa5 or @mikofski I was just curious what "wid" stands for here? Thanks!

https://pvlib-python.readthedocs.io/en/stable/_modules/pvlib/tracking.html#singleaxis

wid = shading.projected_solar_zenith_angle(
    axis_tilt=axis_tilt,
    axis_azimuth=axis_azimuth,
    solar_zenith=apparent_zenith,
    solar_azimuth=apparent_azimuth,
)

[kandersolar]

It's the plaintext version of $\omega_{\text{ID}}$, the symbol for the "ideal tracking angle" in Lorenzo et al 2011, the original reference for that function. Perhaps it's worth a PR to clarify/improve those variable names?