CSU Light Pollution Estimator

Modeling the transition from campus skyglow to Poudre Canyon dark skies.

Model Inputs

Impact of fixture shielding and intensity.

Movement toward the Poudre Canyon.

Clouds amplify skyglow via scattering.

Model Calibration

Baseline ($R_0$): 35× natural sky at Intramural Fields (0.5km center-to-source).

Natural Sky: ~21.7 mag/arcsec²

Decay: Power-law function simulating light transport through the lower atmosphere.

Clear Sky
Visual Simulation
Sky Brightness
--
Relative to Natural
Magnitude
--
mag/arcsec²
NELM
--
Naked-Eye Limit
Visible Stars
--
Estimated Count

How to interpret these results

Upward Light Index (ULI): Reducing this mimics transitioning to 100% full-cutoff LED fixtures. Even at the same distance, lower ULI prevents light from entering the transport path.

Distance Decay: As you move away from CSU toward the Poudre Canyon, the "dome" of light decreases. However, on overcast nights, this dome can be seen from much further away due to cloud reflection.

Bortle Scale Approximation: Class --