Not strictly required.
On Amavasya day, the main focus is on doing tarpanam for our pitru devatas (ancestors). That’s why we generally wait to light the deepam (especially in the puja room) until after finishing the tarpanam. It’s not because it’s wrong to light the lamp before - it’s more about showing priority and respect.
Tarpanam is considered a serious and shraddha karma, where we invite the pitrus symbolically. Lighting a lamp before completing that can be seen as doing something auspicious before completing our duty to the ancestors.
But this is not a hard and fast shastric rule. It’s more of a traditional practice followed for bhakti and emotional reasons. Some families light a small lamp near the tarpanam area or in the southern direction for pitrus, and only later light the regular deepam in the puja room.
So if you’re doing tarpanam at 6 or 7 am, you can wait to light the lamp until after that. If there’s a delay or if someone lights the lamp earlier by habit, it’s not a dosham. Just continue with devotion.
