Occult occultations, computed
Location

Jupiter's moons in July 2027

Io · Europa · Ganymede · Callisto — 2 mutual events

Jupiter's four big moons put on a show every night: they slip behind the planet and into its shadow, cross its face, and drag their shadows across the cloud tops. Any telescope shows it. This is a mutual-event season — the moons' orbits are edge-on to the Sun and they eclipse and occult each other. Pick your place: the calendar and the nights keep only what your sky shows.

Where the moons are

Jupiter · July 2027

Jupiter's equator horizontal, east to the left as in binoculars. Drag through the month, or tap any event below to jump there; full screen (⤢) steps through a single night a minute at a time. Moons behind the planet fade, a moon in Jupiter's shadow is an empty ring, and a shadow on the disc is placed from the listed times. Positions ±0.1 Jupiter radii — for the picture; the times come from JPL.

Events

7 events you can see from New Delhi this month, on 6 nights

Mon
Tue
Wed
Thu
Fri
Sat
Sun
1221
3
4
5
6
7
8191101
11
12
13
14
15
161
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
behind the planetin its shadowcrossing its faceshadow on the planetmoons eclipse or hide each other

Times in IST, when the moon's centre crosses the edge — as almanacs list them. A night runs from noon to noon. Tap an event to see it in the diagram.

Night of Thu 1 Jul

  1. Io crosses Jupiter
    20:19 enters → 22:37 leaves · 2 h 19 min
    Jupiter 23° up · dusk
  2. Io's shadow crosses Jupiter
    21:14 enters → 23:31 leaves · 2 h 17 min
    Jupiter 11° up · dark sky

Night of Fri 2 Jul

  1. Io in Jupiter's shadow
    disappears unseen → 20:49 reappears · 2 h 17 min
    Jupiter 15° up · dark sky

Night of Thu 8 Jul

  1. Callisto in Jupiter's shadow
    20:50 disappears → 01:05 reappears · 4 h 15 min
    Jupiter 11° up · dark sky

Night of Fri 9 Jul

  1. Europa's shadow crosses Jupiter
    17:44 enters → 20:32 leaves · 2 h 48 min
    Jupiter 51° up · daylight

Night of Sat 10 Jul

  1. Io's shadow crosses Jupiter
    17:38 enters → 19:55 leaves · 2 h 17 min
    Jupiter 51° up · daylight

Night of Fri 16 Jul

  1. Europa's shadow crosses Jupiter
    20:19 enters → 23:06 leaves · 2 h 47 min
    Jupiter 12° up · dark sky

Reading the list

Times are for the moment the moon's centre crosses the edge of Jupiter or of its shadow, the convention of published tables; the moon's own disc takes a few minutes to cross. A start or end marked unseen happens behind Jupiter or inside its shadow. “Only what I can see” keeps events with Jupiter more than 10° up in a dark sky. Positions are from JPL DE431 and the jup365 satellite ephemeris, Jupiter as an oblate spheroid with its shadow cone. Mutual-event brightness drops assume uniform discs and are estimates. Events are geocentric — the same instant everywhere on Earth to well under a second.