Map of sky showing extinction values (left) and A_V(Haschke)/A_V(TW) (middle). The dotted outline is the boundary of our tile. Black triangles on a cell indicate that particular cell was made using data that comprise of fewer than 200 stars, detector 16 region outlined in black. Coloured triangles on a cell indicate recalculated extinction ratio (where colour if triangle is recalculated value). Empty cells are where E(J − K_s) ≃ 0 mag (excluded due to producing extreme values in the ratio range). Right: histogram of A_V(Haschke)/A_V(TW), the dashed blue histogram excludes that detector 16 region.