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The Sun


The solar panels of the ROSAT spacecraft are fixed with respect to the XRT axis (Figure 1.1).   In order to maintain a sufficient power supply, the solar panels must always be pointed within a tex2html_wrap_inline16505 cone around the Sun. Consequently, the sky accessible to ROSAT at any given time is a tex2html_wrap_inline16507 band perpendicular to the solar vector (corresponding to tex2html_wrap_inline16509 % of the whole sky). Due to the solar motion, this viewing path covers the whole sky in a period of six months. Targets in the vicinity of the ecliptic plane can be observed twice a year for tex2html_wrap_inline16511 days, whereas targets within tex2html_wrap_inline16513 of the ecliptic poles can be observed at all times. During the reduced pointing phase, the sun angle constraint was tex2html_wrap_inline16515 , as detailed in Sect. 1.2.3 above.

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