From The Stargate Omnipedia
A city of humans from the planet Latona
who abandoned the will to develop technologically in favor of exploring the mind. Any technology that breaks down on their world therefore remains unfixed, as the people no longer possess the knowledge to make the necessary repairs.
The Latonans relied on a particular piece of defense technology, the Sentinel, to prevent the people from falling under Goa'uld occupation by eliminating any who threatened their borders from the world and in orbit. Unfortunately, they were unable to repair it when they learned a rogue N.I.D. unit from Earth had dissected the device and killed it's caretaker, the one person who could utilize the device.
The leader of the Latonans, Marul, was confident that the Sentinel and its caretaker were well and functioning by a candle that burnt bright in his office. He was unaware the N.I.D. team had rigged the candle to continually burn.
With the arrival of SG-1 and the recently imprisoned, former N.I.D. operatives Grieves and Kershaw, they were able to determine that the Sentinel was, indeed, reassembled correctly, and that it had simply been missing its human component. In an act of redemption, Colonel Grieves allowed himself to become the person necessary to interface with the device, thus wiping away the Goa'uld Svarog's presence and preserve the safety of the Latonans once again.
The Latonans are not the first culture humans from Earth have meddled within. It is unlikely, even after the humans repaired the damage, that the Latonans remained welcoming to the race that had been responsible for the loss of so many of their people, and had, after all, nearly sealed the doom of their entire race.
HOMEWORLD - Latona
FIRST APPEARED - The Sentinel
The Sentinel - With the Goa'uld barreling down on Latona, SG-1 turns to two death-row criminals, former N.I.D. operatives, to travel to Latona and repair the Sentinel.