Okay, let's dive into the many shades of blue in Star Wars! It's a surprisingly prevalent color, used symbolically and practically throughout the saga. Here's a breakdown, movie by movie, categorized for clarity. I'll try to be comprehensive, but it's a lot to cover! I'll also note if the blue is specifically significant (like lightsaber color) vs. just background/set dressing.

Important Note: I'm including all theatrical releases (including revised versions) and focusing on visual references. I'm generally excluding things that are described as blue but not seen that way.

I. The Original Trilogy (Episodes IV-VI)

Episode IV: A New Hope (1977)

• Lightsabers: Obi-Wan Kenobi's and Luke Skywalker's lightsabers are a vibrant, classic blue. This is the most iconic blue in the saga.
• R2-D2: The astromech droid is predominantly white, but has significant blue panels and details.
• Luke's Eyes: While often appearing grey or light, a subtle blue is present in Luke's eyes, hinting at his Force sensitivity.
• Holograms: Many holographic projections, including Leia's distress call, are tinted blue. This signifies they aren't 'real'.
• Tatooine Sky: The desert planet often has a pale blue/cyan sky.
• Rebel Pilot Suits: Details on some rebel pilot suits have blue elements.
• Death Star Interiors: Various control panels and lighting have blue accents.

Episode V: The Empire Strikes Back (1980)

• Lightsabers: Continued presence of Luke's blue lightsaber.
• Holograms: Blue tint continues for holographic projections.
• Cloud City: The atmosphere and lighting of Bespin (Cloud City) have a cool, often bluish tone, particularly the gas giants visible outside.
• Yoda's Swamp: Dagobah's swampy environment, while mostly green and brown, often has a blueish mist or light filtering through the foliage.
• Rebel Base on Hoth: The interiors of the rebel base, and the icy landscapes, feature cool blues and whites.
• Carbon Freezing Chamber: The chamber on Cloud City has blue lighting and effects.

Episode VI: Return of the Jedi (1983)

• Lightsabers: Luke's blue lightsaber continues.
• Holograms: Still used for projections.
• Jabba's Palace: While primarily featuring warmer tones, Jabba's palace has some blue lighting and decorations.
• Endor Forest: The forest of Endor often has a bluish cast, particularly in shaded areas or during night scenes.
• Second Death Star: The interior has a lot of blue lighting and paneling.
• Space Battle: Engine trails and energy weapons often have blue components.

II. The Prequel Trilogy (Episodes I-III)

Episode I: The Phantom Menace (1999)

• Lightsabers: Qui-Gon Jinn's and Obi-Wan Kenobi's lightsabers are blue.
• Naboo Royal Starship: A lot of the ship's interior has blue lighting and decorative elements.
• Gungan City: The underwater city of Otoh Gunga has a blue/teal color scheme.
• Holograms: Continued use of blue holograms.
• Coruscant Cityscape: Many of the buildings and lights on Coruscant have blue accents.
• Space Battles: Engine trails and energy weapons often include blue components.

Episode II: Attack of the Clones (2002)

• Lightsabers: Anakin Skywalker and Obi-Wan Kenobi both wield blue lightsabers.
• Geonosis Arena: The arena has a cool, blueish tint to the lighting.
• Coruscant Cityscape: Continues to feature blue lights.
• Jango Fett's Ship (Slave I): Some interior details.
• Holograms: Still used for projections.

Episode III: Revenge of the Sith (2005)

• Lightsabers: Anakin's turns to red, but Obi-Wan still has a blue saber.
• Coruscant Cityscape: Continues to feature blue lights.
• Mustafar: The volcanic planet has contrasting colors, but some of the energy flows/streams have a bluish tinge.
• Holograms: Used during communication scenes.
• Separatist Ships: Some ships feature blue accents.

III. The Sequel Trilogy (Episodes VII-IX)

Episode VII: The Force Awakens (2015)

• Lightsabers: Luke Skywalker still has a blue lightsaber (briefly seen), and Rey ignites a blue lightsaber at the end.
• Resistance Fighters' Uniforms: Some uniforms feature blue elements.
• Takodana (Maz Kanata's Castle): The castle's interior has some blue lighting and decorations.
• Starkiller Base: The base has a lot of cold, blue lighting.
• Space Battle: Energy weapons and engine trails.

Episode VIII: The Last Jedi (2017)

• Lightsabers: Rey and Luke (briefly) have blue lightsabers.
• Crait (Mineral Planet): The red planet is contrasted by the blue support ships and the blue light within the Resistance base.
• Ahch-To: The ocean planet has a predominantly blue color scheme.
• First Order Ships: Some ships feature blue lights.
• Supreme Leader Snoke's Throne Room: The throne room features blue holographic projections and lighting.

Episode IX: The Rise of Skywalker (2019)

• Lightsabers: Rey has a blue/yellow hybrid lightsaber, and Kylo Ren/Ben Solo has a red one.
• Exegol: The Sith planet has a lot of dark, brooding colors, but also some eerie blue light.
• Resistance Ships: Blue is used for identification and accents.
• Space Battle: Engine trails, energy weapons.
• Rey's Force Healing: Often depicted with a blue glow.

IV. Rogue One: A Star Wars Story (2016)

• Jyn Erso's Kyber Crystal: The initial Kyber crystal Jyn holds has a vibrant blue glow.
• Scarif: The tropical planet has a blue ocean and sky.
• Imperial Ships: Some ships feature blue lights.
• Holograms: Used for communications.

V. Solo: A Star Wars Story (2018)

• Space Battles: Engine trails and energy weapons.
• Various Planets: Blue skies and oceans are visible on various planets.

Overall Significance of Blue:

• The Jedi: Primarily associated with the Jedi Order and their lightsabers, representing serenity, knowledge, and peace.
• The Force: Often used to visually represent the light side of the Force, particularly in healing or other benevolent manifestations.
• Technology: Blue is often used for holographic projections and technical displays, signifying information and communication.
• Atmosphere/Environment: Blue skies, oceans, and certain planetary environments add to the visual variety of the galaxy.