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``Data Lost''

Occasionally, pixels get lost while the data are being transferred to the DMS. When this occurs, the correspondence between counts and pixel number is lost and spectra will appear to have shifted in the spatial direction. Pixel-to-pixel sensitivity variations can then not be flat-fielded out. The latest folklore is that this problem disappears when a window is defined for readout; even if you need the entire CCD, it might pay you to formally window it.

manuals store
Tue Oct 7 17:34:45 BST 1997