Travelling Primarch in Atlas


When we see an incoming line (primarch travelling) to a castle, is there a way to find out which primarch is travelling to that castle?

If there is very few/no one else on the castle you can check the primarchs tab to see the primarch, level, and troops.
Another thing you can check is through the primarchs tab again, and see if you are able to trap/hit them. If not, they are likely the one on the way.