The Sun's magnetic field

The first full-disk magnetogram obtained with the new SOLIS Vector Spectromagnetograph (VSM), on August 8th, 2003. This picture was taken with the telescope not in best focus and without the benefit of a flat-field calibration. The geometry is not fully corrected and image tracking was unguided. In spite of these limitations, the noise level is low and this first image indicates that the VSM will provide a significant improvement in the quality of solar magnetic field measurements. See the September 2003 NOAO Newsletter (currently only available in PDF format) for more details of the progress of the Synoptic Optical Long-term Investigations of the Sun (SOLIS) project.