<P> A serious amateur astronomer, Lincoln constructed an observatory at his home in Manchester, Vermont, and equipped it with a refracting telescope made in 1909 by Warner & Swasey with a six - inch objective lens by John A. Brashear Co., Ltd . Lincoln's telescope and observatory still exist; it has been restored and is used by a local astronomy club . Robert Lincoln made his last public appearance at the dedication ceremony in Washington, D.C. for his father's memorial on May 30, 1922 . </P> <P> Lincoln was also a dedicated golfer, and served as president of the Ekwanok Country Club in Manchester . </P> <P> Robert Lincoln was coincidentally either present or nearby when three presidential assassinations occurred . </P> <Ul> <Li> Lincoln was not present at his father's assassination . He was at the White House, and rushed to be with his parents . The president was moved to Petersen House after the shooting, where Robert attended his father's deathbed . </Li> <Li> At President James A. Garfield's invitation, Lincoln was at the Sixth Street Train Station in Washington, D.C., where the president was shot by Charles J. Guiteau on July 2, 1881, and was an eyewitness to the event . Lincoln was serving as Garfield's Secretary of War at the time . </Li> <Li> At President William McKinley's invitation, Lincoln was at the Pan-American Exposition in Buffalo, New York, where the president was shot by Leon Czolgosz on September 6, 1901, though he was not an eyewitness to the event . </Li> </Ul>

Who is the only man known to have witnessed the assassinations of 3 different presidents