Named in honor of Lyyli Heinanen (née Hartonen), a disciple of the discoverer. In 1927, as a student, she assisted in the first attempt to measure a length of 192 m by the Väisälä interference method. It was winter, the weather was very cold, and it seemed that the experiment would fail. She urged that they try once more, and the interferences were found. Later she taught mathematics in secondary school and was for many years chairman of the society Mikkelin Ursa for amateur astronomers. (M 7944) _ _.