Tehran is 7.5 hours ahead of Atlanta
Best overlap: 8:00 AM to 11:00 AM in Atlanta is 3:30 PM to 6:30 PM in Tehran.
If you set up a recurring sync, 8:00 AM to 11:00 AM in Atlanta (3:30 PM to 6:30 PM in Tehran) is the natural home for it. With 3 hours of overlap, 8:00 AM in Atlanta (3:30 PM in Tehran) is a comfortable, repeatable slot for both sides. Finally, Atlanta observes daylight saving and Tehran doesn't, so this window shifts by an hour for part of the year — recheck it each spring and autumn.