GMOS mask slit positions, centred on NGC 7507, at (RA,Dec) = (23^h12^m07^s, − 28°32′23′′). The science slit positions and lengths (4.′′5 − 8.′′0), are represented as vertical blue lines. All slits are 1′′ in width. The circle indicates the largest radius probed by S12. The GMOS field of view is ~ 5.′5 × 5.′5, and a 20′′ bar is shown for scale. North is down and east is to the left.