10^° grid plots for GCs with <500 overlapping sources. The red dot marks the location of the GC, and the red ellipses are the 1σ error ellipses for test binaries in the GC with S/N=10,20,40. The black ellipses are 1σ for MW disc binaries, and the grey ellipses are 2σ. The 2σ ellipses are omitted for M14 (panel 7) to reduce clutter. The background colours indicate the expected number of MW disc binaries in each cell based on their sky location uncertainty distributions.