A rare display of anticrepuscular rays could be seen from Sydney's Tamarama Beach on Thursday evening. These serene shafts of light are a mirrored version of the more frequently observed crepuscular rays and they are caused by sunlight shining through gaps in clouds. Anticrepuscular rays appear to converge on a point of the horizon directly opposite the setting sun, at a spot called the antisolar point. This merging effect is an optical illusion and the beams of light and shadow are actually parallel. On rare occasions, columns of light can be seen stretching across the entire sky joining crepuscular and anticrepuscular rays on opposite horizons. Anticrepuscular rays can occur at any time of year.