SDO Day 55: Cruciforms and Raster Scans
Last evening the EVE cruciform was completed and the high-gain antenna raster resumed. A cruciform scan is a slow scan in a line through the Sun from East to West and another north to South, about 2.5 degrees in each direction. This is used to map out the field of view of the instrument. The high-gain antennas move quite a bit over a year and the raster scans are used to calibrate the pointing of the antennas.