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NUMBER: 239 MODULE: onedspec tasks SYSTEM: V2.10 - V2.10.2 DATE: Sat Mar 5 16:05:55 MST 1994 FROM: valdes BUG: Applying IMSHIFT with a positive shift can cause errors in the ONEDSPEC tasks. Negative shifts do not cause a problem. The same problem has been noted previous in bug log number 180 for IDENTIFY and REIDENTIFY. Errors occur when a wavelength is transformed to a pixel coordinate. This happens in a number of operations in SPLOT. There are various workarounds depending on what is desired. A WCSRESET of the physical coordinate system can be used though this will cause the dispersion coordinates to also shift; i.e. then the shift will move the pixel relative to the image data array and the wavelength coordinate system. As a general rule use of IMSHIFT with spectra, particularly dispersion calibrated spectra, should be avoided. STATUS: The problems have been fixed for V2.11.
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