Naboo — planet of lakes, monarchy and two interwoven societies Naboo Naboo is a fictional planet in the Star Wars universe known for its elected monarchy, the human city-state of Theed, and the aquatic Gungan society; celebrated for art, education a…
Nadir (astronomy, surveying, and remote sensing) Nadir Point directly below an observer defined by the direction of gravity; the opposite of the zenith. Used as a reference in astronomy, geodesy, surveying and satellite imaging; also a…
Naiad (Neptune III) Naiad (moon) Naiad is the innermost known moon of Neptune, a small irregular satellite discovered in Voyager 2 images in 1989. It orbits close to Neptune's cloud tops and has proven difficult t…
Naked eye (unaided human vision) Naked eye Overview of what 'naked eye' means: objects visible without optical aids, limiting factors (visual acuity, brightness, sky conditions), historical and practical importance, example…
Naked singularity A naked singularity is a gravitational singularity without an event horizon, visible to distant observers. Its possible existence challenges predictability in general relativity an…
Narvi — an irregular, retrograde moon of Saturn Narvi (moon) Narvi (Saturn XXXI) is a small, irregular retrograde satellite of Saturn discovered in 2003. It belongs to the Norse group and is thought to be a captured object with a dark, non-s…
Natural satellite A natural satellite is a body held by gravity in orbit around a larger object. Commonly called moons, they range from tiny captured rocks to large planetary companions like Earth's…
Near-Earth asteroid (NEA) Near-Earth asteroid Near-Earth asteroids are small Solar System bodies whose orbits bring them close to Earth's orbit; they are studied for scientific value, resource potential, and impact risk.
Near-Earth object (NEO) Near-Earth object A Near-Earth Object (NEO) is a small Solar System body—asteroid or comet—whose orbit brings it close to Earth's orbit, monitored for scientific study and impact risk assessment.
Nebula (interstellar clouds of gas and dust) Nebula A nebula is a diffuse interstellar cloud of gas and dust where stars form, remnants of stellar explosions, and key laboratories for astrophysics and cosmic chemistry.
Neptune: the Solar System’s distant ice giant Neptune Neptune is the eighth planet from the Sun, an ice giant with powerful winds, a system of faint rings and moons, and a discovery driven by mathematical prediction rather than direct…
Neptune Trojan (co-orbital asteroid of Neptune) Neptune Trojan Small bodies that share Neptune's orbit at the planet's stable Lagrangian points. Neptune Trojans record information about early Solar System dynamics, planetary migration and smal…
Nereid (Neptune II) — irregular outer moon of Neptune Nereid (moon) Nereid is a distant, irregular moon of Neptune, discovered in 1949 by Gerard Kuiper. It has a highly eccentric orbit, an irregular shape about 340 km across, and may be a captured…
Neso (Neptune XIII): the most distant known moon of Neptune Neso (moon) Neso (Neptune XIII) is an irregular, non-spherical moon of Neptune — the most distant known natural satellite in the Solar System, discovered in 2002 and named after a Nereid in 20…
Neutron star A neutron star is an extremely compact remnant of a massive star: mostly neutrons, very dense, strongly magnetized, and often rapidly rotating; observed as pulsars, magnetars, or i…
New General Catalogue (NGC): Catalogue of Nebulae, Star Clusters and Galaxies New General Catalogue A comprehensive overview of the New General Catalogue (NGC): its purpose, contents, history, common uses, and the known errors and revisions that shaped modern deep‑sky identificat…
New Horizons — NASA's Pluto and Kuiper Belt Spacecraft New Horizons New Horizons is a NASA robotic probe launched in 2006 that performed the first close study of Pluto in 2015, flew past Kuiper Belt object Arrokoth in 2019, and continues outbound a…
Newtonian telescope: design, history, and uses Newtonian telescope Overview of the Newtonian reflecting telescope: design principles, main parts, history from Newton’s work to modern amateur use, advantages, limitations, and common variants like t…
NGC 1291 (ring galaxy in Eridanus) NGC 1291 NGC 1291 is a nearby ringed galaxy in the constellation Eridanus, about 33 million light-years away. It features a bright central region, an extended outer ring, and is a target fo…
NGC 1300 — a barred spiral galaxy in Eridanus NGC 1300 NGC 1300 is a prominent barred spiral galaxy about 61 million light‑years away in the constellation Eridanus. It is roughly the Milky Way's size and is a key object for studying ba…
NGC 1569 — a nearby starburst dwarf irregular galaxy NGC 1569 NGC 1569 is a nearby dwarf irregular galaxy in Camelopardalis undergoing intense recent star formation. Its proximity and resolved stars make it an important laboratory for studyin…
NGC 1672 — barred spiral galaxy in Dorado NGC 1672 NGC 1672 is a prominent barred spiral galaxy in the southern constellation Dorado, about 60 million light‑years away, noted for its strong bar, circumnuclear ring of star formation…
NGC 1999 — the Keyhole Reflection Nebula in Orion NGC 1999 NGC 1999 is a reflection nebula in the constellation Orion, notable for a dark, keyhole-shaped cavity that is an empty hole carved by young stellar outflows rather than a dense glo…
NGC 2174 (Monkey Head Nebula) NGC 2174 NGC 2174, commonly called the Monkey Head Nebula, is an emission nebula and star-forming H II region in the constellation Orion, located roughly 6,400 light-years from Earth.
NGC 3521 — Flocculent Spiral Galaxy in Leo NGC 3521 NGC 3521 is a nearby flocculent spiral galaxy in the constellation Leo, noted for its patchy arms, prominent dust lanes and active star-forming regions; accessible to small telesco…
NGC 3603-B (HD 97950B): a massive WN6h Wolf–Rayet star NGC 3603-B NGC 3603-B (HD 97950B) is a very massive, highly luminous WN6h Wolf–Rayet star in the HD 97950 cluster of NGC 3603, roughly 20,000 light‑years away and only a few million years old…
NGC 4102: Spiral galaxy in Ursa Major NGC 4102 NGC 4102 is a spiral galaxy in Ursa Major roughly 69 million light-years away. It has a bright central region and spiral arms, is listed in the New General Catalogue, and is observ…
NGC 4526 — Lenticular galaxy in the Virgo region NGC 4526 NGC 4526 is a bright lenticular galaxy in Virgo notable for its dust lanes, rapid rotation, past supernovae and a massive central black hole. It is an important object for studies…
NGC 4605 — a spiral galaxy in Ursa Major NGC 4605 NGC 4605 is a spiral galaxy in the constellation Ursa Major, located roughly 15 million light-years away. It is listed in the New General Catalogue and has been studied for its str…
NGC 5907 — the edge-on spiral galaxy in Draco NGC 5907 NGC 5907 is a thin, edge-on spiral galaxy in the constellation Draco, about 50 million light-years away. Noted for its slender disk and faint tidal streams, it has been important i…
NGC 6025 — Open cluster in Triangulum Australe NGC 6025 NGC 6025 is an open star cluster in the southern constellation Triangulum Australe, located about 2,700 light-years away. It is a loose group of stars seen toward the southern Milk…
NGC 6193 — open cluster in the constellation Ara NGC 6193 NGC 6193 is a young open star cluster in Ara, containing several massive O- and B-type stars that illuminate the nearby emission nebula NGC 6188 and lie at the heart of the Ara OB1…
NGC 6302 — the Butterfly (Bug) Nebula NGC 6302 NGC 6302 is a bipolar planetary nebula in Scorpius, notable for its extremely hot central white dwarf, dense equatorial dust disk, and striking butterfly‑shaped lobes.
NGC 6334 — the Cat's Paw Nebula NGC 6334 NGC 6334, the Cat's Paw Nebula, is a bright emission nebula and active star-forming complex in Scorpius, roughly 5,500 light‑years away, noted for dense molecular clouds, infrared…
NGC 6503 — a nearby dwarf spiral galaxy in Draco NGC 6503 NGC 6503 is a relatively nearby dwarf spiral galaxy located in the Draco constellation, about 17 million light-years away. It is a compact, isolated system used to study small‑scal…
NGC 6543 (Cat's Eye Nebula) NGC 6543 NGC 6543, commonly called the Cat's Eye Nebula, is a well-studied planetary nebula in Draco. Noted for its intricate shells, hot central star, and X-ray emitting gas, it illustrate…
NGC 6559 — a star-forming nebula in Sagittarius NGC 6559 NGC 6559 is a dusty, star-forming nebula in Sagittarius about 5,000 light-years away. It combines dark lanes, glowing gas and young stars and is studied to understand early stellar…
NGC 6946 (Fireworks Galaxy) — a nearby spiral with frequent supernovae NGC 6946 NGC 6946, nicknamed the Fireworks Galaxy, is a nearby face-on spiral located near the plane of the Milky Way. It is noted for active star formation and an unusually high rate of ob…
NGC 7049 — early-type galaxy with a striking dust ring in Indus NGC 7049 NGC 7049 is an early-type galaxy in the southern constellation Indus, notable for a dark dust ring and a polar gas cloud. It lies at roughly 100 million light-years and illustrates…
NGC 7090 — an edge-on spiral galaxy in Indus NGC 7090 NGC 7090 is a nearby, edge-on spiral galaxy in the southern constellation Indus, located at roughly 30 million light-years. It is studied for disk structure, star formation and ext…
NGC 7538 — Star-forming Nebula in Cepheus NGC 7538 NGC 7538 is a star-forming emission nebula in Cepheus, roughly 9,000 light‑years away. It hosts massive protostars, ultracompact H II regions and bright maser emission, extensively…
Nix (moon) — small irregular satellite of Pluto Nix (moon) Nix is a small, irregular moon of Pluto discovered by Hubble in 2005 and imaged by New Horizons in 2015. It orbits in the plane of Charon, has a roughly 24.9-day period, and a neut…
NML Cygni (V1489 Cygni) — a red hypergiant star NML Cygni NML Cygni is an oxygen-rich red hypergiant in Cygnus. Noted for extreme size, heavy mass loss and a dusty molecular envelope, it is one of the most luminous and largest known stars…
Non-periodic comet (single-apparition and long‑period comets) Non-periodic comet Comets that visit the inner Solar System only once or on timescales longer than 200 years; often from the Oort cloud and sometimes on trajectories that eject them from the system.
Norma: name, constellation, places, culture, and other uses Norma Comprehensive overview of 'Norma' — its use as a personal name, an astronomical constellation and spiral arm, places, works of art, tropical cyclone name, and other notable meaning…
Norma (constellation) Norma is a small, faint southern constellation representing a carpenter’s square or ruler. Introduced in the 18th century, it lies between Scorpius and Centaurus and contains parts…
Norma Cluster (Abell 3627) — a massive galaxy cluster near the Great Attractor Norma Cluster The Norma Cluster (Abell 3627) is a rich, nearby galaxy cluster lying in the Zone of Avoidance near the Great Attractor. It is massive and X-ray bright but largely hidden by Milky…
North America Nebula (NGC 7000) North America nebula An H II emission nebula in Cygnus whose outline resembles the North American continent. Catalogued as NGC 7000 / Caldwell 20, it lies roughly 1,600 light-years away and is an activ…
