There were so many interesting exhibits at the Vienna Museum of Technology, but I especially enjoyed the, astronomical spectrometers.  I had not realized that spectrometers were used to catigorize stars for as long as they have.  I recall that the first spectrometers used on stars were  made in the 1700's. These devices are interesting as is can be used to determine the surface temperature and composition of stars simply by analyzing the light emmited from extreme distances.  This advanced our understanding of the life cycle of stars as new stars have more intense hydrogen lines than older stars.  With these instruments, astronomers could point the spectrometer at a star, star cluster, or other stellar formation and determine how old(where they are in their stellar life cycle) they are.  The power of the instrument is impressive but the exhibit was easy to pass by.  #ASTRONOMYisLI(gh)T.