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XMM-Newton Science Analysis System


evproject (attcalc2-1.5) [xmmsas_20211130_0941-20.0.0]


Projecting the events

The projection direction (ie, the direction of the point at which the projection plane is tangent to the celestial sphere) is user-selectable from the following alternatives, chosen via the parameter tangdirstyle:

As said in the introduction, the `pixel size' of the X and Y values is fixed at 0.05 arcsec; the remaining thing to be specified is the maximum allowed X and Y values. This is specified in a somewhat roundabout way via the parameter imagesize, which specifies the total half-width and/or half-height of the projection plane in decimal degrees. After offsetting by imagesize, X and Y can therefore run from 1 to $2 \times$ imagesize $\times 3600 / 0.05$.

XMM-Newton SOC -- 2021-11-30