Atlantis begins after season seven and runs in parallel with season eight. A fairly big plot device from the SG1 season eight finale is then used in the Atlantis season one finale.
Sorry, it’s been a while since I had to figure it out, since I just have one big master playlist for all of Stargate in broadcast order, and it sort of interleaves season 8 of SG1 with season, 1 of Atlantis (and all subsequent seasons of both), so, yeah, it runs them parallel with each other, like you said
Atlantis begins after season seven and runs in parallel with season eight. A fairly big plot device from the SG1 season eight finale is then used in the Atlantis season one finale.
Sorry, it’s been a while since I had to figure it out, since I just have one big master playlist for all of Stargate in broadcast order, and it sort of interleaves season 8 of SG1 with season, 1 of Atlantis (and all subsequent seasons of both), so, yeah, it runs them parallel with each other, like you said