Free Light Pollution Impact Calculator
Estimate how light pollution reduces contrast by computing the sky-brightness ratio: contrast_loss = sky_brightness / (sky_brightness + object_brightness).
mag/arcsec2
mag/arcsec2
Sky-to-Object Flux Ratio
15.8489
Object Contrast (%)5.94 %
Sky-to-Object Flux Ratio vs Sky Brightness
Light Pollution and Contrast
Light pollution raises the sky background, drowning out faint objects.
Key Relation
The flux ratio of sky to object is:
ratio = 10^((mag_obj - mag_sky) / 2.5)
A higher ratio means the sky overwhelms the target. Object contrast is approximately 1 / (1 + ratio).
Darker skies (higher mag/arcsec2) dramatically improve contrast for faint targets.
Example Calculation
Sky = 19 mag/arcsec2 (suburban), object = 22 mag/arcsec2.
- 01ratio = 10^((22 - 19) / 2.5)
- 02ratio = 10^1.2 = 15.85
- 03contrast = 100 / (1 + 15.85) = 5.94%
- 04The object has only 5.9% contrast against the bright sky.