The asteroid named for Mildred Shapley Matthews was lost in the solar system for 75 years.
In 1916 the 60 inch Hale telescope on Mt. Wilson, California was the largest telescope in the world.
Seth Nicholson and Harlow Shapley used it to discover a 2 mile diameter asteroid. They only observed their new asteroid twice on their discovery night. Shapley named the asteroid Mildred for his one year old daughter. Nicholson and Shapley were able to find asteroid Mildred a couple of times during the month after it's discovery. After that it's 1324 day orbit around the Sun was so poorly defined that astronomers did not know where to point their telescopes to observe it and Mildred was declared "lost". Friends of Mildred Shapley Matthews would always ask her if she was found yet. In fact it was not until she was 76 years old that Dr. Gareth Williams rediscovered "lost" asteroid Mildred. After 3/4 of a century of being lost Mildred was found.