L. Sprague de Camp's Theodolite

Origin
Lyon Sprague de Camp was a surveyor and engineer who later became a famed writer of science fiction, fantasy, non-fiction and biography. In a career spanning 60 years, he wrote over 100 books, including novels and works of non-fiction, including biographies of other fantasy authors. He was a major figure in science fiction during the genre's heyday in the 1930s and 1940s. Many of his fictional works involved time travel or alternate history explained by logical methods that he thought were possible. One of his most famous novels, “Lest Darkness Fall”, features the main character teleporting back to 6th century Rome in a crack of lightning.

Effects
Enables the user to go back in time and change the past, altering the future and everyone in the vicinity. This alternate timeline lasts for only one day unless the artifact is used again to keep changing events. If the activator uses the theodolite a second time, everyone and thing they had touch will be erased after they return to the reality. When in use, large amounts of lightning occur.