A Hertfordshire man called 999 after spotting a mysterious object hovering above his house - only to find out it was the moon.The man made the call, not thought to be a prank, in a state of panic saying the object's "lights were blazing".However, just moments later the caller phoned back the operator to say he had mistaken the UFO for the moon.The call was released by Hertfordshire Police to remind callers not to block the emergency lines over the busy Hallowe'en weekend.The man is heard telling police he can see a mysterious flying object coming towards his house with lights blazing.He said he was in the Canterbury and Stevenage area. The call handler asked him if he could hear engine noises but he said he couldn't.The call handler spends several minutes writing up his description of the sighting and then says she will contact the local police team to see if they know anything about it.Jason Baxter, assistant manager at the force communications room, said: "I would like to encourage people before they phone 999 to ask themselves is this really a police matter?"