Yes, it is. 'Vast of Night' is based on true events which add an air of authenticity to the film. It draws from real - life experiences to create its unique atmosphere and plot.
The general setting might be one aspect. If the true story was set in a particular era or location, that could be reflected in the movie. Also, any strange occurrences or events in the true story could be adapted into the plot of 'Vast of Night'.
I don't know for certain. It could be based on some truth or could be the author's imagination. You'd have to research more or ask the author to know for sure.