Jupiter in opposition19/08/2021 @ 21:30 - 23:00 - 14th August. The day in Jupiter is closest to our planet and thus, the best night to observe it and its moons. Observatório do Lago Alqueva19 August, 2021 When 19/08/2021 21:30 - 23:00 Add To Calendar Download ICS Google Calendar iCalendar Office 365 Outlook Live The day Jupiter is closest to our planet and thus, the best night to observe it and its moons.