(Left) Optical depth τ_J map derived from 2MASS data. The resolution of the map is 180″. (Right) τ₂₅₀/τ_J map with resolution 180″. The black contours are drawn on τ₂₅₀ levels 0.0016, 0.0008, and 0.0004. The green contours are drawn on τ_J levels 2, 1, and 0.5. Areas where τ_J < 0.0001 or τ₂₅₀ < 0.00004 are masked. The area marked with a yellow rectangle was used as a background when subtracting the background from the two optical depth maps.