Document Collection Contents The document collection contains documentation files, where available, for this bundle. All document files will have an accompanying label file to describe content and structure. Label files have the same name as the main document file, with an extension of ".xml". pds3_instrument_description.txt - PDS3_instrument_description - This is the originally submitted, PDS3 Instrument description, which contains additional information to the more general PDS4 entry. pds3_observatory_description.txt - PDS3_observatory_description - This is the original PDS3 observatory / host description, which contains additional information to the more general PDS4 entry. bundle_description.txt - Bundle description for the gbo.ast.smass.spectra bundle - A document describing the content and structure of the bundle. ref.txt - Reference List - The reference list for the bundle. observatory.mdm.txt - Description document for McGraw-Hill Observatory - Description document for McGraw-Hill Observatory mdm.hiltner2m4.txt - Description for 2.4-m Hiltner Ritchey-Chretien equatorial reflector at McGraw-Hill Observatory - Description for 2.4-m Hiltner Ritchey-Chretien equatorial reflector at McGraw-Hill Observatory mark_iii_spectrograph.txt - Description Document for Mark III Spectrograph - A description of the Mark III Spectrograph instrument AA_Document_Index.txt - Document Index - The file you are reading. collection_gbo.ast.smass.spectra_document_inventory.csv - Collection Inventory - An inventory of document products in this collection.