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Дата изменения: Tue Aug 16 05:51:18 2005
Дата индексирования: Sat Dec 22 08:46:12 2007
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XMM-Newton Science Analysis System


newsiam (newsiam-1.5.1) [xmmsas_20050815_1803-6.5.0]

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• Example: The SIAM should be changed such that the RGS angle of incidence onto the gratings $\alpha$ is increased by 10arcsec. Due to the focusing of the XRT, thus amounts to an off-axis angle of
  
  $$\frac{L}{F}\,\Delta\alpha = \frac{67}{75}\times 10 = 8.9333$$
  
  
  The dispersion of the RGS is along the Z-axis, and the gratings are arranged such that an increase of $\alpha$ is achieved by a rotation of the spacecraft around the Y-axis in positive sense. Hence the task is called with
  
  newsiam ry=8.9333
• occasionally the minimization fails at the SLATEC level (SLATEC error from DNLS1E). This cannot be circumvented, but slightly different values of one of the input parameters remedy this.