The Polaris Galaxy is a galaxy featured in the Ratchet and Clank franchise. It has been included in Tools of Destruction and its sequels.
Overview
The Polaris Galaxy is a star system consisting of four sectors and 18 planets. It was first introduced in Tools of Destruction, where the majority of the galaxy was controlled by Tachyon. It also hosted the great war, between the Lombaxes and the Cragmites. The resulting battle caused both races to nearly become extinct, but seems to have recovered for the most part, except for Fastoon, which is still in ruins. The galaxy also experienced problems with space pirates, with Captain Slag running many illicit activities.
Planets
Cerullean Sector
________________________________________________

Tachyons Gelatonium plant
Planet Cobalia
Cobalia also known as the "Gel Capital of the Polaris galaxy", is a swamp planet best known for being the Polaris Galaxy's richest source of Gelatonium, the most commonly used spacecraft fuel in the galaxy. GrummelNet's famous Confuzzler Gas was dervired from the seeds of the Cobalian Worm Plant. Basilisk Leviathans are commonly found in caves and jungles on Cobalia.
When Emperor Percival Tachyon
took over Cobalia, he gained control over the largest source of
Gelatonium in the galaxy, making the rest of the galaxy dependent on
Tachyon's rationing of Gelatonium fuel for all interstellar travel.

Cobalia from space

Stratus City
Planet Kortog
Kortog is home to Stratus City which is a city that was suspended high above the planet. It is a part of Tachyon's empire and used to be the Educational District of the Polaris Galaxy before Tachyon invaded. You will get a new gadget called Robo-Wings
on this planet. The city is full of robo-wing launchers that the player
could fly anywhere in the city and explore.Its famed hall of knoledge
is said to hold the secrets of the Great War and the history of both
the Lombaxes and Cragmites. However, the hall of knoledge has been
strictly off limits after Tachyon conquered the city.
This was where Ratchet and Clank discover a Lombax planet called Fastoon. The otherwise reddish color was probably let off by the number
of red coloured architechture throughout the planet, along with amount
of red-coloured gases seen throughout the cities.

Kortog from space

A destroyed Lombax city
Planet Fastoon
Planet Fastoon was once the homeworld of the Lombax race and is desert planet. The planet was ravaged by
Tachyon's Drophyd troopers and his Enforcers who mercilessly decimated
the Planet years ago when Ratchet was just a child. The planet is now
solely occupied by Nanophyte scavengers. The scavengers look for the any pieces of lombax technology that hasnt been destroyed.
Ratchet
comes here in an esacape pod so he has to find a new ship to get off
the planet. It is here where they find the Lombax engineered fighter,
Aphelion who tells them a bit more about the fate of the Lombaxes
Fastoon from Space

The imperial Fight Festival
Planet Mukow
Mukow is a stormy aquatic planet in the Cerullean Sector. It was home to Emperor Percival Tachyon's Imperial Fight Festival, an exclusive battle resort for Tachyon's most elite Drophyd
troopers. Tachyon used the Fight Festival as a means to both entertain
his troops, to capture his enemies or lure them into fighting to their
deaths. At such an occasion, Tachyon put the Holo Pirate Disguise as a prize in the Festival in hopes of luring Captain Slag there to his doom.
Surrounding the gladiator arena of the Fight Festival was a
large carnival park. The carnival park featured things such as a large
and deathly ferris wheel and Emperor Tachyon's Trail of Turning Terror.
The area near the entrance to the arena was heavily guarded by
non-vacationing Drophyd troops and Enforcers.

Mukow from space

Fighting on the asteroids
Nundac Asteroid Ring
The Nundac Asteroid Ring is the location to Apogee Space Station where Ratchet and Clank meet Talwyn, Cronk, and Zephyr. This was also the place where the Zoni give Clank the Geo-Laser Gadget. This area is also a Basilisk breeding ground and has a good source of raritanium and some small gel
sources. The asteroids in the ring are all named after the Greek
alphabet. The Smuggler is here and he will trade you bolts for killing
basilisks.

There are pirates on Ardolis
Planet Ardolis
Ardolis is a water filled planet with some cliffs sticking out from the seas and the planet and was home to the pirate base. On this planet, Ratchet and Clank attempted to explore the base in hope to find the Lombax secret.
They
find a mysterious Lombax artifact that only Ratchet can activate.
However, this turned out to not be Lombax secret, instead it is a map
to another planet. which only turned out to be coordinates to another planet.
Ratchet and Clank first met Captain Slag and his right-hand man Rusty Pete on Ardolis. 
Ardolis from space
Verdigris Sector
___________________________________________

The lava Refineris
Planet
Rykan V
This volcanic wastleland was site of Lombax activity in
previous years. This is why Tachyon took over this planet to search for
Lombax tech. The lava refineries of Rykan V are the source of the
metals used in most advanced weapons and armor in the galaxy. After
retrieving the artifact from the planet Ardolis, it showed the Rykan V globe hologram where Ratchet, Clank, and their new allies Talwyn, Cronk and Zephyr could find the Lombax Secret. .
When the heroes found the door for any Lombax return, they found a movie tape that told that the Lombax Secret was a gadget called the Dimensionator.
Rykan V from space

There are dinosaurs on Sargasso
Planet Sargasso
Planet Sargasso is a dangerous and mostly uninhabitable
primordial swampland. The planet was infested with large, deadly
creatures who would quickly make a snack out of any unwary Lombax
explorer. The only advanced race known to travel to the planet were the
fiercely territorial Kerchu.
Being advanced architects, they had built Gelatonium Derricks,
refineries, and gel plants to take advantage of the large amounts
accessable, plus the fact that the planet was not yet under Imperial
control.
The Lombax race once had a Testing Facility for all their
latest weapons and gadgets, the most notable being the Dimensionator.
Sargasso from space

The IRIS
Kreeli Comet
The Kreeli Comet is a comet and the location to the IRIS Supercomputer but was taken over by Captain Slag and his Robot Pirates. It is an icy comet, with caves and caverns.
The
IRIS Supercomputer is the most ancient and powerful computer in the
galaxy. Who created it and why has been long forgotten, but IRIS
continues to be used as a form of intergalactic encyclopaedia and
oracle. Some believe that the sheer computing power and massive storage
of this supercomputer give the eerie ability to predict the future. The
computer has been stolen by space pirates so you have to fight and
sneak your way through the comet to access the computer.
The icy comet, Kreeli

Zordoom Prison
Planet Viceron
Viceron was the dismal planet where treacherous Zordoom Prison was located. There were constant breakouts which were
hunted down by the guards stationed on the planet. Many of the past
enemies and "bad" characters of past Ratchet and Clank games had been
jailed here like Dr. Nefarious, Ace Hardlight, and Slim Cognito.
The planet itself is very dark with murky waters and dark brown rocks.
There wasn't alot of vegetation and it seemed uninhabited, besides the
prisoners and imperials. The majority of the area was water with tall
rocks coming out, where the Zordoom prison was built on that was large
enough to be seen from orbit.
Viceron from space
Praxus Sector
___________________________________________

Kerchu City
Planet Jasindu
Planet Jasindu in Praxus Sector was a jungle planet that was the home of the Kerchu species, with Kerchu City
on the planet being the capital of the Kerchu domain. GrummelNet's
Intergalactic travel guide considered Jasindu the worst vacation spot
in the Polaris galaxy due to the Kerchu's habit of killing any
outsiders who wandered into their building sites. The planet was rich
with Gelatonium, and the Kerchu have several underground Gelatonium
plants near Kerchu City.
After finding the Dimensionator on Rykan V, Max Apogee
relocated it in Kerchu City to keep it away from Captain Slag. What
happened to Max was unknown, but the Kerchu of Kerchu City were later
guarding the Dimensionator.
Jasindu from space

Captain Slag
Ublik Passage
The Ublik Passage was the location of Slag's Fleet. This was where Ratchet and Clank defeated Captain Slag. The Ublik Passage was previously used for connection between the Praxus and Verdigris Sectors, however after being taken over by Slag's Fleet it was unaccessable.The Slag's Fleet in Ublik Passage was an inhospitable space station where the pirates docked there ships. Here Ratchet fought Slag's army of robot pirates, including Swabs and two Rogues. He also had to fight many pirates and a ship raid while on a pirate ship.

Slags Base

Cragmite ruins
Planet Reepor
Reepor was the Cragmite home world that had been dormant for years thanks to the Lombaxes. It was home to the Cragmite Ruins. They encountered Emperor Percival Tachyon who had the Dimensionator and used it to bring back the Cragmites. Ratchet and Clank got seperated and had to regroup Talwyn, Cronk, and Zephyr.
The planet itself was very dark and creepy looking. The "water" was
green in color, and most of the plants and soil was black (making it
look very dark and burnt from orbit). 
Reepor from space
Planet Igilak
Igliak is a planet in the Praxus Sector of Polaris, orbiting a radioactive sun and was the home of Meridian City, the capital of Free Polaris. Meridian City is probably the largest city of the galaxy as well, well comparable with Metropolis of the Solana galaxy and Megapolis of the Bogon galaxy.
During the Great War of Polaris, the warbot Zephyr was stationed in the Zenith Outpost in Meridian City. Later, during the perilous Phylax intrusion, he was joined by another warbot named Cronk, who later became his lifetime partner. The two were later sent on a mission to secure a Gelatonium
Refinery on the planet to be able to transport fuel to the Meridian
Armory. The refinery was infested by undead zombie dung dragons created
by Igliak's radioactive sun.

Igilak from space
Drogol Sector
_______________________________________________________

The bay of Hoolefar island
Merdegraw
a tropical planet in the Drogol Sector of the Polaris galaxy. It was unregulated by both Tachyon's Cragmite Empire and Free Polaris because of the thriving pirate activity on it. The planet was home to the locations: Hoolefar Island, Morrow Caverns and Darkwater Cove. The enormous ocean separating all these areas was called the Azorean Sea.
The primary sentient species of Merdegraw were purple, reptilian beings known as Hoolefoids. The caves of Merdegraw are also inhabited by Heliogrubs, small creatures that glow in the dark when they are afraid, and more notoriously, Pythors, large, fire-spitting monsters resembling the Basilisk Leviathan.