<span class="SFPTagline"> From SCIFIPEDIA </span>

A Tollan ion cannon is an advanced weapons technology in the Stargate universe. Created by the advanced race of humans, the Tollans, the ion cannons were the main planetary defense of the Tollan's new planet Tollana. One ion cannon is capable of destroying a Goa'uld Ha'tak vessel, but when used in conjunction with a system of ion cannons, is capable of defeating an entire fleet of Ha'tak.

The technology uses the Tollan technology of phasing through matter, enabling the weapons to bypass Goa'uld shields. The devices were too advanced to be reverse engineered by the Tau'ri at their level of technology and the Tollan initially refused to share the technology. When the Tollan curia reversed the Tolan position on sharing technology with less advanced races, SG-1 visited the planet to make the deal in exchange for trinium. A planet the size of Earth would require at least thirty ion cannons in order to protect the planet completely. SG-1 later learned that Anubis' advanced shields had made his ships impervious to the ion cannons make them useless to the humans and the Tollan alike.

The technology is believed to have been lost when the Tollan were wiped out by the Goa'uld.

Key episodes

• "Pretense"
• "Between Two Fires"