Combined Callisto and Ganymede measurement with the PACS photometer at 70 μm. The two sources were separated by about 55′′ and moved with different apparent motions (see Table 5) at the time of the observations. Top: PACS observing frames centered on Callisto (right source). Bottom: centered on Ganymede (left source). The angular separation is about 6′ between Jupiter and Callisto and about 5′ between Jupiter and Ganymede, with an apparent angular diameter of Jupiter of 40.7′′.