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The XRT all-sky survey: Exposure Times

Figure 6.1 gif shows a contour plot on an Aitoff projection of the celestial sphere representing the (logarithmic) exposure time (in seconds) of the ROSAT all-sky survey. The spring equinox is located at the center of Figure 6.1 gif, with increasing right ascensions plotted to the left. The lowest contour indicates an (unvignetted) exposure of 250 s, and each new contour represents an exposure increase by a factor of two. Unshaded areas indicate regions with exposures of less than 250 s. As is obvious from Figure 6.1 gif, such regions are of extremely limited extent. The exposure time increases sharply towards the poles of the ecliptic with relatively large latitudinal exposure variations present, especially at southern latitudes.

Michael Arida
Tue Jun 11 16:18:41 EDT 1996