It’s #SunDay#! Here’s your space weather report for the week of May 15 - 21: • 4 M-class flares • 3 C-class flares • 35 coronal mass ejections • 1 geomagnetic storm This video from NASA’s Solar Dynamics Observatory (SDO) shows the week’s activity. It was a fairly calm week on the Sun. A coronal mass ejection last week reached Earth on May 15, triggering a minor geomagnetic storm and leading to aurora sightings across the northern U.S. On May 20, SDO's Helioseismic and Magnetic Imager (HMI) paused normal science operations for a series of routine calibration maneuvers — measurements that keep the instrument's magnetic field and Doppler velocity data scientifically accurate. You can see these maneuvers starting at about 2:29 in the video. Learn more about space weather: