About: http://webisa.webdatacommons.org/395626809

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	The assembly comprising the objective lens, the mirrors, and the structure is preferably made of the same material, such as aluminum, Invar, or a ceramic having a low coefficient of expansion.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com.au