Helen Mark celebrates December's Blue Moon with artist Elspeth Owen, who is living outside and walking every night as part of an eccentric and unique project. When there are two full moons in one calendar month, the second of those moons is called a Blue Moon. Elspeth Owen, who is in her 70s, has decided to live outside between the first full moon (on the 2nd of December) and the second full moon (on the 31st). She wants to discover something about the dark, about fear and about using her senses differently. For this Open Country special, Helen Mark visits Elspeth, who lives in the Cambridgeshire village of Grantchester, when the sky is at its darkest - mid-way through her project.