were sent to the Moon along with an image of Comet Hale-Bopp, "the last comet that the Shoemakers observed together." In 1997, when Bopp pointed out the comet would soon disappear from view and would not be visible for another 2380 years, he said he would always continue looking up at the stars. He continued to volunteer at observatories near Phoenix, Arizona, towards the end of his life, speaking about Hale–Bopp. He died of liver failure on January 5, 2018, at the age of 68. References External links Comet Hale-Bopp Homepage at JPL Comet Hale–Bopp Timeline – 1997 1949 births 2018 deaths Amateur astronomers American astronomers Discoverers of comets People from Denver People from Youngstown, Ohio Military personnel from Colorado Youngstown State University alumni Deaths from liver failure