© NASA/Cassini

Jupiter at opposition

Tue, 08 May 2018 at20:28 EDT(165 days away)
00:28 UTC

Dominic Ford, Editor
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Ashburn
The sky at

Jupiter will be well placed for observation, in the constellation Libra. It will be visible for much of the night, reaching its highest point in the sky at around midnight local time.

From Ashburn (click to change), it will be visible between 20:45 and 05:30. It will become accessible at around 20:45, when it rises 7° above your south-eastern horizon, and then reach its highest point in the sky at 01:10, 34° above your southern horizon. It will become inaccessible at around 05:30 when it sinks to 8° above your south-western horizon.

Jupiter opposite the Sun

This optimal positioning occurs when Jupiter is almost directly opposite the Sun in the sky. Since the Sun reaches its greatest distance below the horizon at midnight, the point opposite to it is highest in the sky at the same time.

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 the Sun in the sky, the solar system is lined up so that Jupiter, the Earth and the Sun form a straight line with the Earth in the middle, on the same side of the Sun as Jupiter.

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.

On this occasion, Jupiter will lie at a distance of 4.40 AU, and its disk will measure 43.8 arcsec in diameter, shining at magnitude -2.5. Even at its closest approach to the Earth, however, 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.

Jupiter in coming weeks

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.

A chart of the path of Jupiter across the sky in 2018 can be found here, and a chart of its rising and setting times here.

The position of Jupiter at the moment it passes opposition will be:

Object Right Ascension Declination Constellation Magnitude Angular Size
Jupiter 15h04m00s -16°00' Libra -2.5 43.8"

The coordinates above are given in J2000.0.

The sky on 08 May 2018
Sunrise 06:02
Sunset 20:07
Twilight ends
21:52
Twilight begins
04:18

22-day old moon
Age of Moon
22 days

All times shown in EDT.
Rise Culm. Set
Mercury 05:09 11:32 17:55
Venus 07:38 15:05 22:33
Moon 02:32 07:43 12:54
Mars 01:15 06:00 10:45
Jupiter 19:56 01:10 06:19
Saturn 23:52 04:42 09:28

Source

The circumstances of this event were computed using the DE405 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

08 May 2018, 20:28 EDT  –  Jupiter at opposition
10 Jun 2019, 11:17 EDT  –  Jupiter at opposition
14 Jul 2020, 03:48 EDT  –  Jupiter at opposition
19 Aug 2021, 20:18 EDT  –  Jupiter at opposition

Image credit

© NASA/Cassini

Ashburn

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