About a month after the first Abydos mission, Daniel Jackson, who had remained behind on the planet, discovered a cartouche in an ancient map room near the Abydos pyramid. The huge wall was covered with glyphs and symbols, all of which are on the Abydos stargate, and many of which represent constellations visible in the Abydos night sky. The cartouche was determined to be a chart or map of a vast network of stargates all over the galaxy, with the symbols representing all the stargate addresses known to the Goa'uld. The discovery of the cartouche enabled the SGC to make the necessary calculations for stellar drift that would allow the dialing computer to successfully connect to other planets beyond Abydos.
For some time it was believed that all stargates were represented on the cartouche, however, following the mission to P3R-272, during which the knowledge of the Ancients was downloaded into O'Neill's brain, O'Neill entered new programming into the main SGC computer to identify many new stargates not shown on the Abydos cartouche, and therefore not known to the Goa'uld. Currently the SGC database includes stargate address references from both the Abydos cartouche, indicated in yellow, and the Ancients' original map added by O'Neill, indicated in red.
Cross Reference: Abydonians, Abydos, Ancient Repository, DHD, Stargate
Episode Reference: Children of the Gods, The Fifth Race, Maternal Instinct, 2001