by Dominic Ford, Editor
Last updated: 24 Mar 2020

Pluto recently passed behind the Sun at solar conjunction. From Seattle, it is not readily observable since it is very close to the Sun, at a separation of only 10° from it.


Pluto, as seen by New Horizons. Image courtesy of NASA.

Pluto is a dwarf planet which orbits in an outer region of the solar system known as the Edgeworth-Kuiper belt. Its formal minor-planet designation is 134340 Pluto.

From its discovery in 1930 until 2006, Pluto was considered to be the solar system's outermost known planet. However, it is much smaller than the other planets, measuring 18% of the diameter of the Earth, and less than half the diameter of the next smallest planet, Mercury.

In the early 2000s, its status as a planet became increasingly untenable due to theoretical predictions of large numbers of other similarly-sized objects in the Edgeworth-Kuiper belt.

Pluto was at last downgraded from its status as a planet in 2006, and given the newly-generated title of dwarf planet. This was prompted by the discovery of another Edgeworth-Kuiper belt object, which was 27% more massive than Pluto. In view of its role in history, that object was named Eris, after the goddess of strife of discord in Greek mythology; Eris was also classified as a dwarf planet.

Apparitions of Pluto

The table below lists apparitions of Pluto around the year 2023, computed from NASA's DE430 planetary ephemeris. To show events around other years, use the control below.

Change year



Apparitions of Pluto around 2023

Date Event Declination
Date Event Declination
01 Jul 2013 22:29 PDT134340 Pluto at opposition19°49'S
04 Jul 2014 06:43 PDT134340 Pluto at opposition20°16'S
06 Jul 2015 14:35 PDT134340 Pluto at opposition20°41'S
07 Jul 2016 21:40 PDT134340 Pluto at opposition21°05'S
10 Jul 2017 04:07 PDT134340 Pluto at opposition21°26'S
12 Jul 2018 09:54 PDT134340 Pluto at opposition21°46'S
14 Jul 2019 15:00 PDT134340 Pluto at opposition22°04'S
15 Jul 2020 19:41 PDT134340 Pluto at opposition22°19'S
17 Jul 2021 23:35 PDT134340 Pluto at opposition22°34'S
20 Jul 2022 02:48 PDT134340 Pluto at opposition22°46'S
22 Jul 2023 05:23 PDT134340 Pluto at opposition22°57'S
23 Jul 2024 07:30 PDT134340 Pluto at opposition23°06'S
25 Jul 2025 08:46 PDT134340 Pluto at opposition23°13'S
27 Jul 2026 09:31 PDT134340 Pluto at opposition23°19'S
29 Jul 2027 09:46 PDT134340 Pluto at opposition23°24'S
30 Jul 2028 09:25 PDT134340 Pluto at opposition23°27'S
01 Aug 2029 08:41 PDT134340 Pluto at opposition23°28'S
03 Aug 2030 07:07 PDT134340 Pluto at opposition23°29'S
05 Aug 2031 05:23 PDT134340 Pluto at opposition23°28'S
06 Aug 2032 03:08 PDT134340 Pluto at opposition23°26'S

Finding Pluto

Pluto comes to opposition once every 367 days – its synodic period – almost exactly once a year. The date it comes to opposition moves only one day later each year.

Pluto is a faint and distant object. At around magnitude 14, it is beyond the reach of all but the largest amateur telescopes. Pluto's largest moon, Charon, is not much smaller than Pluto itself, measuring a little under 10% of the diameter of the Earth, and appears 2–3 magnitudes fainter. Two other much smaller moons, Nix and Hydra, were discovered in 2005.

A chart of the time of day when Pluto rises and sets on any given day of the year can be found here. A chart of Pluto's path relative to the background stars can be found here.

Pluto has only ever been visited once by one spacecraft: the NASA New Horizons probe flew past it in 2015 before going on to study other Edgeworth-Kuiper belt objects.

NORAD ID COSPAR ID Name Launch date Flight ended Owner
NORAD ID COSPAR ID Name Launch date Flight ended Owner
28928 2006-001A NEW HORIZONS 19 Jan 2006 United States

More »





Color scheme