The Stirling Cooper Open Space sign is on the backside of Aspen Mountain. The 54-acre Stirling Cooper Open Space area was formally recognized Sept. 4, 2016 with the unveiling of the sign honoring Stirling Cooper Jr., a popular Aspen resident who died at the age of 38 in a tragic hiking accident in Utah on Aug. 28, 1999. See this link for more information on the sign: http://www.aspentimes.com/news/a-dads-wish-granted-to-honor-his-son-with-park-on-back-of-aspen-mountain/
Also see these 4 pages:
Stirling Cooper is buried in the Aspen Grove Cemetery in Aspen, Colorado. His gravestone shows his name as "Stirling M. Cooper, Jr." and his dates of birth and death as November 13, 1960--August 28, 1999. See section below and also this page: https://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GSln=pfeifer&GSfn=friedl&GSbyrel=all&GSdyrel=all&GSst=7&GScntry=4&GSob=n&GRid=69734329&df=all&
A photo of the Open Space sign is below; click on the image to enlarge it.
Below are photos from the Aspen Grove Cemetery, taken by the author in September 2016.