As the leader of the Environmental Light Measurement Laboratory (Eszterházy Károly Catholic University, Eger, Hungary), I have been studying the quality of the starry sky. I have taken photographs of many places, which give an accurate picture of the state of the night sky.

With the naked eye, the night sky is colourless. We can determine what the sky would look like if we could see it from the photographs. We can also use the pictures to create a world of colour that tells us much about the sky’s mysteries.

The film shows the results of our study on the quality and the variation of the colours of the night sky. People usually think that the night sky is blue. We believe this because, during the last period of twilight, when our eyes can still see the sky, it has a deep blue hue. Spectra taken under the pristine sky can tell us precisely the actual colour of the night sky, even when our eyes can no longer see it.