The picture on the left is the discovery image of the sodium tail in comet Hale-Bopp taken on 16 April, 1997. The tail appears as a very straight narrow feature extending from the head of the comet to the upper left. The picture on the right is an image of comet Hale-Bopp showing the usual ion and dust tails of the comet, taken a few minutes before the discovery of the sodium tail. The dust tail is the broad tail pointing straight upwards, while the ion tail is the filamentary structure to the left. Comparison of the two images shows how the sodium tail has a completely different appearance to the other tails of the comet.