Can 'system' object be in a use case diagram?

Question

I'm making a scheduler viewer.

Is putting a system on the opposite side of the user possible like an attached photo?

I know that a person can be there but the system is not a person so I'm asking:)

Thank you!

Answer 1

An actor may indeed be a person (your actor on the left) or a system (your actor on the right).

However, an actor is always external to the system you are modelling. So it can be a different system (i.e. an independent system which is interfaced with your Schedule Viewer system), but not the subject of the diagram (so it can't be Schedule Viewer system itself).

Important remark: I assume that you left the rectangle empty, because your question is only about actors and that in reality you have some use-cases inside. If not, the use-cases would be something fundamental that is missing ;-).