XMM-Newton Science Analysis System


attbin (attcalc2-1.5.1) [xmmsas_20230412_1735-21.0.0]

Limits on attitude wander

The limits on attitude wander are defined via the parameter maxdelta, which is in arcseconds. The RA limit $\Delta \alpha$ is set to

  $$\Delta \alpha = {\rm maxdelta} / \cos(\delta),$$ (1)

where $\delta$ is the average declination value (the exact meaning of `average' in this context is discussed in section 3.3 below). The declination limit is just set to maxdelta, and the position angle (apos) limit $\Delta p$ is set to

$$\Delta p = {\rm maxdelta} \times 60 \times 180 / \pi / R_{\rm {arcmin}},$$

where $R_{\rm {arcmin}} = 15.0$ is the nominal radius of the field of view of the XMM EPIC cameras.