1861
When the Civil War broke out, the agreement with the University of Mississippi failed and the lens was idle.
1862
While testing the new lens, the white dwarf companion of the brightest star in the sky, Sirius, was discovered and named Sirius B. It was the first compact stellar remnant ever discovered. At this time, M. R. Foret persuaded the Chicago Astronomical Society and the University of Chicago to build an observatory.
1863
Hayne purchased Mr. Clark's lens for the Chicago Astronomical Society and the University of Chicago. He put down $1500; the total price was $18,187. Construction of the observatory building was started, paid for by J. Y. Scammon, who named it for his deceased wife, Mary Ann Haven Dearborn. Mrs. Dearborn was a relative of Henry Dearborn, after whom Fort Dearborn was named.