(a) Calling by court. The court may, on its own motion or at the suggestion of a
party, call witnesses, and all parties are entitled to cross-examine witnesses
(b) Interrogation by court. The court may interrogate witnesses, whether called
by itself or by a party.
(c) Objections. Objections to the calling of witnesses by the court or to
interrogation by it may be made at the time or at the next available opportunity
when the jury is not present.