"...The Tritons dancing in a ring
Before his palace gates do make
The water with their echoes quake,
Like the great thunder sounding:T
he sea-nymphs chant their accents shrill,
And the sirens, taught to kill
With their sweet voice,
Make ev'ry echoing rock reply
Unto their gentle murmuring noise
The praise of Neptune's empery."
Thomas Campion (1567-1620)
NEPTUNE DATA:
Distance from Sun:
Aphelion 4,553,946,490 km
Perihelion 4,452,940,833 km
Equatorial Diameter:
48,600 km
Mass:
1.0243×1026 kg
(17.147 Earths)
Composition:
80±3.2% Hydrogen
19±3.2% Helium
1.5±0.5% Methane
~0.019% Hydrogen deuteride
~0.00015% Ethane
Ices: Ammonia, water, ammonium hydrosulfide, methane
Moons:
13
Orbital Period:
164.81 yrs
Rotational Period:
15hrs 48mins
Apparent magnitude:
+8.02 to +7.78
Angular diameter:
2.2″–2.4″
MAJOR MOONS (Diameter)
Triton (2,700 km) discovered by W. Lassell 1846.
Nereid (340 km) discovered by G. Kuiper 1949.
Neptune is a telescopic object only discernable as a tiny bluish disk.
Details of rise and set as well as relevant monthly information can be found on the Sky This Month page.
Hubble's Neptune Anniversary Pictures - 12 July, 2011
Today, Neptune has arrived at the same location in space where it was discovered nearly 165 years ago. To commemorate the event, NASA's Hubble Space Telescope has taken these "anniversary pictures" of the blue-green giant planet.
Neptune is the most distant major planet in our solar system. German astronomer Johann Galle discovered the planet on September 23, 1846. At the time, the discovery doubled the size of the known solar system. The planet is 2.8 billion miles (4.5 billion kilometers) from the Sun, 30 times farther than Earth. Under the Sun's weak pull at that distance, Neptune plods along in its huge orbit, slowly completing one revolution approximately every 165 years.
Videos:
TRIDENT - Triton Pass and Neptune Orbit. This is a simulation of the UT Aerospace Engineering senior design group TRIDENT's orbit around Neptune using the open-source Celestia software.
TRIDENT (The Really Interesting Discoverer and Explorer of Neptune and Triton) is a senior design mission that includes a Neptune orbiter as well as atmospheric probe. Seen in this video is the first Triton pass of the mission as well as a couple more orbits to show the views of Neptune available from the orbiter (POSEIDON).