Scales relevant to the possible emission regions around η Car. Because some regions, such as the large and the little Homunculus nebulae, are asymmetric or have sizes that can change over time, such as for the shock cap, the sizes shown cover a large range of values. The different extensions are as follows: 1–20 au (shock cap, A); 10–6.4 × 10³ au (wind region, B); 2 × 10³ to 6.5 × 10³ au (little Homunculus, C); 2.1 × 10³ to 21.69 × 10³ au (Homunculus, D); and > 50 × 10³ au (Carina Nebula, E). The black and grey bars in the upper-left corner indicate the distances beyond which the absorption at 200 GeV is less than 50% (black) and the absorption at 600 GeV is less than 10% (grey), see text for more details. The individual images are from Parkin et al. (2011), Clementel et al. (2014), Smith (2005), HST, and ESO.