Note: X and Y are coordinates (light years on XY plane) relative to Terra at (0, 0)
|X:Y Coordinates||-125.75 : -475.26[e]|
- 2571 - Magistracy of Canopus 
- 2577 - Magistracy of Canopus 
- 2582 - Magistracy of Canopus (occupied by SLDF/FWLM troops from November)
- 2596 - Magistracy of Canopus 
- 2750 - Magistracy of Canopus 
- 2764 - Magistracy of Canopus 
- 2765 - Magistracy of Canopus 
- 2767 - Magistracy of Canopus 
- 2822 - Magistracy of Canopus 
- 3025 - No record 
- 3040 - No record 
- 3050 - No record 
- 3052 - No record 
- 3054 - No record 
- 3057 - No record 
- 3059 - No record 
- 3063 - No record 
- 3067 - No record 
- 3079 - No record 
- 3081 - No record 
- 3085 - No record 
- 3130 - No record 
- 3135 - No record 
- 3145 - No record 
Settled at some point point prior to the Age of War,, by the time of the Reunification War Tetski was a heavily industrialized world located at the rimward edge of the Magistracy of Canopus and was one of the few worlds to have extensive BattleMech repair facilities. Despite how far Tetski was from the border with the Free Worlds League it had both military garrison on the world and a contingent of WarShips assigned to the system permanently. During the Reunification War the Magistracy Armed Forces constantly rotated 'Mech battalions through Tetski for repair and refit, making Tetski a key industrial world in the overall plan for defending the Magistracy.
Tetski became a target for the Star League Defense Force invasion of the Magistracy of Canopus during the fifth year of the military campaign. The SLDF task force commanded by Captain-General Marion Marik launched their attack on Tetski in September 2582; a deep strike into Magistracy territory, this attack was intended to strike a blow directly at the industrial and military fabric of the Magistracy. Defending Tetski at the time was the 3rd Canopian Light Horse and the naval contingent consisting of a pair of corvettes, and it was these forces that responded when two battalions of the 1st Marik Militia arrived in-system and began harrassing orbital traffic on the 3rd of September 2582. The city of Sendai was the site of a major refinery and the chosen target for the Militia's landing; the Militia made planetfall and tore through the local garrison before leading the 3rd Canopian Light Horse on a five-day chase through the wilds of the northern wilderness, constantly avoiding a direct engagement. While the Light Horse outnumbered the Militia and the Canopian naval picket prevented the Militia from leaving the planet, the Light Horse couldn't bring their greater numbers to bear against the Marik forces.
A week after the Marik Militia first appeared in-system, the SLDF task force launched the second stage of the attack on Tetski. A combined force consisting of the SLDF 58th Brigade along with the 5th Marik Militia and the 3rd Brigade of the Fusiliers of Oriente appeared at a pirate point less than ten hours out from Tetski and tore through the orbiting Canopian pickets, the SLDF and Marik WarShip escorts gutting both Canopian corvettes before dropping the 'Mech forces onto the planet. The Light Horse found themselves about to be heavily outnumbered and trapped in open terrain, and immediately broke off the attack on the 1st Marik Militia to race back to the city of Tokhai as fast as possible. The Light Horse made it back to the planetary capital just as the first contrails from dropping 'Mechs appeared in the sky above them.
The SLDF forces quickly surrounded Tokhai, but now faced a determined foe dug into a highly defensible position with access to substantial reserves of food and equipment. A three week-long siege allowed the SLDF forces to push their way into Tokhai, slowly securing all of the various economic, industrial and political areas of importance within the capital despite the determined resistance offered by the Light Horse; when the commanding officer of the SLDF contingent offered generous terms for surrender, the Light Horse refused and instead fought to the last man, inflicting heavy casualties on both sides before the unit was finally destroyed. Despite the price paid for it, the capture of Tetski was a heavy blow to the economic and military infrastructure of the Magistracy as well as a sign that the initiative was slipping away from the MAF in their fight against the forces of the Star League.
Although the SLDF would occupy Tetski for the remainder of the war, the system would remain a part of the Magistracy of Canopus; during the Star League era, Tetski founded the mining world of Adhara as a vassal planet and the two would continue to prosper until Tetski had to be abandoned during the 29th century. In a twist of fate, whilst Tetski had to be abandoned during the war between the Magistracy and the Taurian Concordat because of the release of biological agents on the world, Adhara survived, despite being exposed to those same bioligical weapons.
- 2 MAF corvettes
- MAF 2nd Fleet (2579 only)
- 1st Canopian Grenadiers (2578-2580)
- 3rd Canopian Light Horse (2582 only)
- Handbook: Major Periphery States, p. 93, "Magistracy of Canopus after Age of War  and fall of the Star League "
- Historical: Reunification War, p. 94, "Reunification War: Magistracy of Canopus Front Deployments (2577)"
- Historical: Reunification War, p. 101-2, "Tetski (September-November 2582)"
- Historical: Reunification War, p. 158, "Inner Sphere -  Map"
- Era Report: 2750, p. 37, "Inner Sphere -  Map"
- Field Manual: SLDF, p. vii, "Inner Sphere -  Map"
- Historical: Liberation of Terra Volume 1, p. 11, "Inner Sphere -  Map"
- Field Report 2765: Periphery, p. 35, "Magistracy Armed Forces Deployment Map - "
- Historical: Liberation of Terra Volume 1, p. 96, "Magistracy of Canopus -  Map"
- Historical: Liberation of Terra Volume 2, p. 122-123, "Inner Sphere -  Map"
- Handbook: Major Periphery States, p. 96, Magistracy of Canopus after Age of War, p. 96, "Magistracy of Canopus after Third Succession War  and after FedCom Civil War "
- Historical: War of 3039, p. 133, "Inner Sphere -  Map"
- Era Report: 3052, p. 11, "Inner Sphere -  Map"
- Era Report: 3052, p. 23, "Inner Sphere -  Map"
- Objective Raids, p. 46, "Map of Periphery States"
- Era Report: 3062, p. 11, "Inner Sphere -  Map"
- The Periphery, 2nd Edition, p. 112, "Magistracy of Canopus & Tortuga Dominions"
- Era Report: 3062, p. 29, "Inner Sphere -  Map"
- Inner Sphere (sourcebook), p. 97, "Near Periphery Kingdoms"
- Jihad: Final Reckoning, p. 43, "Inner Sphere -  Map"
- Field Report: Periphery, p. 20, "Magistracy of Canopus Region Deployment Map - [August 3079]"
- Jihad: Final Reckoning, p. 62, "Inner Sphere -  Map"
- Field Manual: 3085, p. vii, "Inner Sphere - "
- Map of the Inner Sphere 3130
- Era Report: 3145, p. 11, "Inner Sphere -  Map"
- Era Report: 3145, p. 39, "Inner Sphere -  Map"
- Field Manual: 3145, p. VI, "Inner Sphere -  Map"
- Historical: Reunification War, p. 148, "Magistracy Of Canopus Front(Jump-Off - 2582)"
- Historical: Reunification War, p. 150, "Magistracy Of Canopus Front(Jump-Off - 2582)"
- Era Report: 2750
- Era Report: 3052
- Era Report: 3062
- Era Report: 3145
- Field Manual: 3085
- Field Manual: 3145
- Field Manual: SLDF
- Field Report: Periphery
- Field Report 2765: Periphery
- Handbook: Major Periphery States
- Historical: Liberation of Terra Volume 1
- Historical: Liberation of Terra Volume 2
- Historical: Reunification War
- Historical: War of 3039
- Inner Sphere (sourcebook)
- Jihad: Final Reckoning
- Jihad Secrets: The Blake Documents
- Map of the Inner Sphere 3130
- Objective Raids
- The Periphery, 2nd Edition