![]() In order to enhance the reflectivity, all mirrors are coated with gold. Such mirrors are fabricated using a nickel-galvanoplating process similar to the one used for XMM-Newton. The length of the paraboloid- hyperboloid pairs is 300 mm. The optical design of the mirror modules requires shells with a wall thickness between 0.2 and 0.4 mm and diameters between 76 and 163 mm. The geometry of the mirror systems is optimised in order to achieve maximum sensitivity between 0.5 and 10 keV. The on-axis resolution is 25'' (half energy width, HEW). Each of the mirror systems contains 27 nested shells. The seven mirror systems are tilted with respect to each other by 2-3° and are mounted on a common fixture plate. We will copy them for ROSITA thereby reducing the risk of a new development. The ABRIXAS mirrors (Figure 16) also had this geometry (Egle et al., 1998). ![]() Although there are many possible configurations, only Wolter-I optics (parboloid + hyperboloid) have got real importance in X-ray as- tronomy. ![]() The electric power consumption will be below 100 W (without active cooling). We esti- mate the total weight including the mechanism to be 220 kg. The telescope tube has a length of about 2,500 mm, its diameter is about 800 mm. The exact aspect determination is done post facto using the ROSITA star tracker data. ![]()
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