Zeroth-order 1D FWHM vs Time, 24 October 2005

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Summary

The FWHM of the 1D projection of the zeroth-order "trailed image" (streak) for HETGS observations has been monitored for six-and-a-bit years. The width of the PSF can be broader for sources with harder spectra, so filtering on E<2keV or E<3keV has been applied in these cases in more recent analyses. From the plot here it appears the FWHM is very constant without any long-term trend.

The 1D FWHM was measured using the "streak" events as described in Measured and Modelled zeroth-order 1D projections.


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Software and Data File
See earlier focus trends updates for onfo on software; the latest focus_trends.rdb file is available here.