[Solved] Can a Ployed Formation perform Artillery Fire & Skirmishing?
I assume you are referring to the skirmish part of the Artillery & Skirmishing Phase? Potentially, there is a 45o arc and 450 yard range, lastly, the Unit must be deployed to contribute to Artillery & Skirmishing; i.e. within those limitation laid out in Artillery & Skirmishing, they may do so (all this per 5.1).
Artillery must be committed and unlimbered with a target within 45o arc and 900 yards – with a clear lane of fire, defined as the width of the artillery base, to the target. If artillery meets those criteria, it fires (again per 5.1).