How does the spacecraft wobble appear in the exposure map?
The spacecraft wobble is always along the same rib. It is often easily visible by looking for the "fuzziest" support rib and picking the rib 90 degrees away (the fuzziest rib is perpendicular to the wobble direction), or by looking for the "sharpest" support rib, which will be parallel to the wobble direction. For a more exact answer, the folklore says to "rotate" your ROSAT image by the roll angle, and then the wobble direction is from the upper left to the lower right corner. Be aware, however, that there have been cases of non-wobbled observations (visibly obvious as ALL of the support ribs are equally sharp), as well as one opposite-direction wobble.
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