Jupiter at opposition

Dominic Ford, Editor
From the Outer Planets feed


Objects: Jupiter

Jupiter will reach opposition, when it lies opposite to the Sun in the sky. Lying in the constellation Leo, it will be visible for much of the night, reaching its highest point in the sky around midnight local time.

From Cambridge, it will be visible between 19:19 and 06:25. It will become accessible at around 19:19, when it rises to an altitude of 7° above your eastern horizon. It will reach its highest point in the sky at 00:52, 52° above your southern horizon. It will become inaccessible at around 06:25 when it sinks below 7° above your western horizon.

2028 apparition of Jupiter

12 Jan 2028 – Jupiter enters retrograde motion
12 Mar 2028 – Jupiter at opposition
12 Mar 2028 – Jupiter at perigee
13 May 2028 – Jupiter ends retrograde motion

A close approach to the Earth

At around the same time that Jupiter passes opposition, it also makes its closest approach to the Earth – termed its perigee – making it appear at its brightest and largest.

This happens because when Jupiter lies opposite to the Sun in the sky, the Earth passes between Jupiter and the Sun. The solar system is lined up with Jupiter and the Earth on the same side of the Sun, as shown by the configuration labelled perigee in the diagram below:


When a planet is at opposition, the solar system is aligned such that the planet lies on the same side of the Sun as the Earth. At this time, the planet makes its perigee, or closest approach to the Earth. Not drawn to scale.

The panels below show a comparison of the apparent size of Jupiter when seen at opposition in 2028, and when it is most distant from the Earth at solar conjunction.

Jupiter at 2028 opposition
Jupiter at solar conjunction

A comparison of the size of Jupiter as seen at 2028 opposition and at solar conjunction.

In practice, however, Jupiter orbits much further out in the solar system than the Earth – at an average distance from the Sun of 5.20 times that of the Earth, and so its angular size does not vary much as it cycles between opposition and solar conjunction.

Observing Jupiter

At opposition, Jupiter is visible for much of the night. When it lies opposite to the Sun in the sky, this means that it rises at around the time the Sun sets, and it sets at around the time the Sun rises. It reaches its highest point in the sky at around midnight local time.

But even when it is at its closest point to the Earth, it is not possible to distinguish it as more than a star-like point of light with the naked eye, though a good pair of binoculars is sufficient to reveal it as a disk of light with accompanying system of moons.

A chart of the path of Jupiter across the sky in 2028 can be found here, and a chart of its rising and setting times here.

At the moment of opposition, Jupiter will lie at a distance of 4.44 AU, and its disk will measure 43.4 arcsec in diameter, shining at magnitude -2.5. Its celestial coordinates at the moment it passes opposition will be:

Object Right Ascension Declination Constellation Magnitude Angular Size
Jupiter 11h33m40s 4°29'N Leo -2.5 43.4"

The coordinates above are given in J2000.0.

Over the weeks following its opposition, Jupiter will reach its highest point in the sky four minutes earlier each night, gradually receding from the pre-dawn morning sky while remaining visible in the evening sky for a few months.

The sky on 12 Mar 2028

The sky on 12 March 2028
Sunrise
06:58
Sunset
18:46
Twilight ends
20:20
Twilight begins
05:24


Waning Gibbous

93%

16 days old

Planets
Rise Culm. Set
Mercury 06:15 11:27 16:39
Venus 08:35 15:40 22:44
Moon 19:03 00:46 07:19
Mars 07:08 13:00 18:51
Jupiter 18:33 00:52 07:12
Saturn 08:27 14:59 21:31
All times shown in EDT.

Source

The circumstances of this event were computed using the DE430 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).

This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.

Related news

12 Mar 2028  –  Jupiter at opposition
13 May 2028  –  Jupiter ends retrograde motion
10 Feb 2029  –  Jupiter enters retrograde motion
11 Apr 2029  –  Jupiter at opposition

Image credit

© NASA/Cassini

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