Unknown to Lowell, his surveys had captured two faint images of Pluto on March 19 and April 7, 1915, but they were not recognized for what they were.
Tanpa sepengetahuan Lowell, surveinya menangkap dua foto Pluto yang kabur pada tanggal 19 Maret dan 7 April 1915, tetapi statusnya belum diketahui saat itu.