Observations: A photographic journey that was inspired by the number 24

Twenty-four might not strike you as a particularly significant number, but for one group of photographers it is. Six years ago, all 24 of them were studying together on a postgraduate photography course at Central St Martin's when they decided to collaborate on an exhibition documenting the first 24 hours of the New Year with 24 images. Each photographer drew lots for their hour and took a photograph of whatever, wherever they liked. The show was such a success that they decided to continue the project – you've guessed it – for 24 years.

This year's show, until 19 March, is twofold. The Viewfinder Photography Gallery in Greenwich has all 144 images taken so far on display while a special, waterproof outdoor installation in Greenwich Park focuses on this year's set of images. Some of the original photographers have been replaced with new people and every year, each photographer moves on by one hour. This year's images include a pregnancy test kit entitled "Beginnings", by Candida Jones, and red, swirly letters spelling out "Wahre Liebre", which means true love, by Christoph Grothgar.

"We're growing up together as a collective," says photographer and costume maker Alison Wagstaffe, who this year dressed up as Cinderella at a bus stop, with a pumpkin at midnight for her self-portrait image, "Carriages Midnight". "Last year was very sombre, 12 artists all lost a parent and if you look at the images together they're very poignant. This year's images are a lot happier; everyone's getting married and having children and that state of mind is reflected." Stay tuned to find out what next New Year's Eve will bring.

www.24photography.org; www.viewfinder.org.uk