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1.2.1 Uniform Archive

One of the primary assets of the IUE archive is the long timeline of observations taken with a remarkably stable photometric instrument. To exploit this asset, observations must be fully intercomparable over the entire lifetime of IUE. In order to satisfy the first requirement, that of uniformity, it was essential to develop a fully automated system that allowed no human intervention and was sufficiently robust to process all images acquired by IUE. Thus the algorithms developed were designed to yield the best overall result for all types of images. These algorithms may not yield the best result for a particular image or particular class of images because of this design requirement. This represents a change in philosophy from IUESIPS. For example, the data were processed with IUESIPS according to Guest Observer (GO) specifications concerning the width of the extraction slit and the registration of the spectrum with respect to the pseudo extraction slit. In the NEWSIPS low-dispersion system, the width of the extraction slit is automatically determined and registration is always automatic. The NEWSIPS high-dispersion system uses a boxcar extraction where the width of the extraction slit is set according to an automated source type determination (i.e., point or extended). As is the case in low-dispersion, the high-dispersion registration is also always automatic.


next up previous contents
Next: 1.2.2 New Processing Algorithms Up: 1.2 Philosophy of the Previous: 1.2 Philosophy of the
Karen Levay
12/4/1997