During the 1670s, it was discovered that these events were occurring about 17 minutes later than expected when Jupiter was on the far side of the Sun.
V 70-tych rokoch 17. storočia sa zistilo, že tieto javy nastávajú asi 17 minút po vypočítanom čase, keď sa Jupiter nachádza na vzdialenejšej strane Slnka.