Same skyglow physics as the 3D version, rebuilt as three linked 2D-native panels instead of a rendered scene. Walker's Law (Walker, 1977) gives the artificial sky-brightness contribution at the zenith:
B_art / B_natural ≈ k · P / d^2.5
P = city population (light output proxy)
d = distance from city centre, km
k = clarity constant (haze raises it, dry clear air lowers it)
Total sky brightness combines the natural airglow baseline (≈21.9 mag/arcsec² at a pristine zenith) with the artificial term on the magnitude scale:
m_sky = 21.9 − 2.5·log₁₀(1 + B_art/B_natural)
The road map plots distance on a log scale so both "just outside town" and "300 km into the desert" are readable at once, with a glow gradient sized by the same ratio. The brightness curve plots that same log-log Walker relation directly, with your current point marked. The fisheye sky is a genuine polar all-sky chart (zenith at centre, horizon at the rim — the same projection real all-sky cameras use) seeded from a synthetic 2,800-star catalogue whose magnitudes follow the real stellar luminosity function (≈2.5× more stars per magnitude step); only stars brighter than the computed limiting magnitude are drawn.
- Population — bigger cities dump proportionally more lumens skyward through unshielded fixtures, roof glow and vehicle headlights.
- Distance — the single biggest lever for a stargazer: the d^2.5 falloff means driving 10× farther from a city cuts its glow contribution by roughly 300×.
- Atmospheric clarity — haze, humidity and aerosols scatter city light sideways and upward, amplifying skyglow at any fixed distance; dry, clean high-altitude air suppresses it.
- Bortle scale — the standard 1 (pristine) to 9 (inner-city) naked-eye sky-darkness scale, derived here from the computed sky brightness.
Real-world relevance: this is the same class of model light-pollution researchers and dark-sky park planners use to draw the buffer distance a new observatory or nature reserve needs from the nearest city, and it is the physical basis for why International Dark Sky Places are sited far from major population centres.