00493nam a2200157Ia 4500003000900000008004100009040001600050080001500066100001100081245011000092260003600202300001200238650003300250650004100283700001100324IN-BaIIA211028s9999    xx            000 0 eng d  cIIA Library  a520.9bBAU  aBausch 0aCertified precision diffraction gratingscBausch and  Lomb                                                 aNew YorkbBausch and Lombc1981  ai, 22p.  aAstronomical instrumentation  aAstronomy and astrophysics thesaurus  aBausch