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Observing Neptune through a telescope
Neptune is the eighth and farthest known planet orbiting the Sun. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet.
What Neptune is
Neptune is the eighth and farthest known planet orbiting the Sun. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth. Compared to Uranus, its neighbouring ice giant, Neptune is slightly smaller, but more massive and dense. Being composed primarily of gases and liquids, it has no well-defined solid surface. Neptune orbits the Sun once every 164.8 years at an orbital distance of 30.1 astronomical units. It is named after the Roman god of the sea and has the astronomical symbol, representing Neptune's trident.
Observing Neptune through a telescope
Neptune is fainter still and appears as a tiny blue-grey dot even in larger telescopes. Finding it with a chart and confirming its disc is the reward, rather than any visible detail.
Planets and the Moon reward higher magnification than deep-sky objects, but only up to what the air will allow: on a turbulent night the image boils and less power shows more. Magnification is your telescope's focal length divided by your eyepiece's focal length, so a shorter eyepiece gives more power. Use the Fit My Telescope tool to see the magnification and exit pupil each of your eyepieces gives before you observe.
Neptune in NASA imagery
NASA has imaged Neptune in detail. One example in the NASA Image and Video Library is titled Neptune Rings, from JPL. NASA imagery is in the public domain.
What magnification suits Neptune?
Open the Fit My Telescope toolSee the magnification and exit pupil each eyepiece givesFind telescope eyepiece on eBayaffiliateRelated
Sources: Neptune (Wikipedia, CC BY-SA) · Wikidata (CC0) · NASA Image and Video Library: PIA01493 (public domain)