Rainbow Machine? Imaged recently by Denis Joye (site) in a park at St Cloud near Paris. Everyone has seen a rainbow and yet they are actually much more rare than many other optical effects. Perhaps this fire tender is a desparate measure to create one! At any one location in parts of Europe a rainbow might be seen only 6-12 times a year. Special circumstances are needed, strong sunlight, falling rain opposite the sun and raindrops extraordinarily close to spherical. A deviation of only 1-2% from sphericity impairs a rainbow. This bow from drifting fire tender spray is characteristically broader than usual - a sign that it was formed from a mist of fine drops. Image ©Denis Joye , shown with permission.