... Up: Software Applications . ... We discuss how and why FITS data should be encapsulated in XML. ... A probable path in this cycle could be: data are taken at the telescope as FITS, they are submitted to a publisher in L A T E X , the publisher converts these data into SGML, data centers convert the SGML into some form of ASCII (such as HTML), and the end-user downloads this and converts the data back into FITS (!) for use in various analysis software. ... XDF and FITSML are works in progress. ...