In real life, constellations don't actually exist as discrete groupings of stars — what we perceive as constellations are simply casual patterns created by our perception of the night sky as a two-dimensional surface, and the individual stars within them are usually very far away from one another. Furthermore, because their shape is specifically the product of where their stars are located compared to Earth, they also only exist from a point of view in the solar system — extrasolar worlds would have alien night skies with entirely different constellations. However, it's a common astronomy error in science fiction is to treat constellations as though they were clusters of stars that are actually physically near each other, and to treat these as major astronomical areas and reference points. Often, this results in characters or cultures being described as being "from the so-and-so constellation", and in constellations being used to describe where a specific location is within the broader universe.
This trope typically uses real-life constellations, as part of the assumption that constellations are universal constants. However, some works may invent Fictional Constellations that will be used in the same manner. Such uses are arguably more justified — while the stars in real constellations are not clustered close together, there is no reason why a fictional constellation might not be so. Alternately, the meaning of the word "constellation" may have shifted in-universe to refer to stars that are actually in the same region, as interstellar travel made it necessary to have some convenient way to refer to such things.
Worth noting that this does happen with (some of) the stars in certain constellations, such as Ursa Major, Orion, or Scorpius, that share a common origin and are relatively close to each other. However, even in this case, these stars often hundreds of light-years from each other.
Subtrope of Artistic License Space.
- The Five Star Stories is set in a group of star systems that are physically near each other, which many characters refer to as a constellation.
- Blade Runner: During his famous speech at the climax, Roy Batty mentions having seen attack ships on fire "off the shoulder of Orion".
- The Fifth Element: The cruise ship is stated to be orbiting the planet Phloston in the "Angel" constellation.
- Men in Black: Discussed, lampshaded and ultimately subverted. A dying alien tells the heroes that "the Galaxy is on the Orion's Belt", which they first take to refer to the strip of stars forming the "belt" of the Orion constellation. However, they are quickly refuted when they are shown that the "belt" in reality consists of stars millions of light-years apart that only look like they are close together from Earth, and that there are no suitable galaxies in that particular direction of the sky. The alien's words turn out to refer to their pet, also named Orion, who carries a tiny galaxy hidden on their collar.
- Space Mutiny: Constellations are repeatedly referred to as meaningful divisions of space.
- Stargate: Played With. The titular gate uses constellations as reference points for a three-dimensional coordinate system (six constellations, one for each side of a cube, plus one non-constellation symbol for the starting point). The gate on Abydos has completely different constellations though, and Daniel has to find the coordinates for Earth for the expedition to go home. Stargate SG-1 and subsequent TV series quickly discard the "unique constellations" aspect and treat the symbols on the gates as a simple entry code for different planets, with extragalactic travel using seven constellation symbols and a point of origin (and extra power).
- In The Stainless Steel Rat a planet is described as being "Second planet of a B star in Corona Borealis", but the setting is a sprawling interstellar civilization in which Earth (and the whole Solar System) is either unimportant, or even (in later books in the series) destroyed and its location no longer known.
- Doctor Who:
- Throughout the classic series, "constellation" is used as a synonym for "galaxy". The Doctor admits to being from "outside the constellation" several times, and that Gallifrey is (or was) in the constellation of Kasterborous. This happens so often that a later Expanded Material book justifies it by claiming that it's a result of meaning changing due to interacting with other spacefaring species who measure sectors by specific groups of stars rather than the present meaning.
- "The Trial of a Time Lord" — the season 23 story arc — repeatedly refers to Earth's entire constellation being moved by advanced aliens, ravaging Earth in the process.
- 3rd Rock from the Sun: The aliens' homeworld is located in the border territory between the Cepheus and Draco constellations.
- JumpStart Adventures 3rd Grade: Mystery Mountain: The observatory Mini-Game has you figuring out which constellation Polly sent her father's spaceship to.
- Katamari Damacy: Constellations are physical groupings of stars until they were all destroyed by the King of All Cosmos on a drunken bender, and your job is to build new ones to place back in the sky.
- Star Control II: All the stars in a constellation are close to each other, forming contiguous regions on the hyperspace map. The manual explains that these constellations are not the same constellations visible from any given planet, but were created after hyperspace was mapped from the patterns on the map.
- Il était une fois... L'Espace: Cassiopeia is said to control the neighboring constellations of Cepheus, Draco, and Andromeda, and aliens are described as coming from constellations such as Auriga or Centaurus.