Left panel: H I emission in the Arp 94 system (in red) on top of a deep optical image from Mundell et al. (1995b). Central panel: composite g + r deep optical image from MegaCam/CFHT using an “arcsinh stretch” to emphasise faint emission (Duc et al. 2014). Both the left and central panels come from Appleton et al. (2014). Top-right panel: blow-up of the g + r composite image showing the location of the TDG in H I emission as blue contours, equivalent to an extinction of 0.4, 1.4, 2.4, and 3.4 A_B magnitudes, ranging from 4 × 10²⁰ to 4 × 10²¹ cm⁻² (Mundell et al. 2004); the annotations indicate the area where a high optical extinction is seen towards the background galaxy (north-east) and the star-forming region in the south, as well as the demarcation line at Dec = 19° 51′50″ that we apply to distinguish the northern from the southern part of the TDG. Bottom-right panel: star-forming region in the south of the TDG as revealed by young clusters visible in HST WFC3/F547M imaging and Hα emission from Mundell et al. (2004) shown as contours (0.8, 2, 3, and 4 × 10³³ erg s⁻¹ pc⁻²).