B1 – B2
True dark
Milky Way casts a shadow. Hanle, Spiti.
Tool III · Light pollution atlas
Where the sky is darker.
World Atlas 2022 by David Lorenz. Brighter overlay means worse sky — drag to find your nearest dark patch.
Bortle scale
B3 – B4
Rural
Best for deep-sky imaging. Sariska, Coorg.
B5 – B6
Suburban
Bright nebulae only. Outskirts of mid-sized cities.
B7 – B9
Urban
Planets and Moon. Inner-city centres.