For the Solar-B mission, we are building an X-ray telescope (XRT) similar to the SXT, but with significant improvements in spatial resolution and in temperature response that take into account the knowledge gained from Yohkoh.

XRT is a grazing-incidence (GI) modified Wolter I X-ray telescope, of 35 cm. inner diameter and 2.7m. focal length. The 2048 by 2048 back illuminated CCD has 13.5m pixels, corresponding to 1.0 arcsec and giving full Sun field of view. This will be the highest resolution GI X-ray telescope ever flown for solar coronal studies, and it has been designed specifically to observe both the high and low temperature coronal plasma. A small optical telescope provides visible light images for co-alignment with the Solar-B optical and EUV instruments.