SOLIS: an innovative suite of synoptic instruments


SOLIS (Synoptic Optical Long-term Investigations of the Sun) is a suite of three innovative instruments under construction that will greatly improve ground-based synoptic solar observations. The Vector Spectromagnetograph (VSM) is a compact, high-throughput vector-polarimeter with an active secondary mirror, an actively controlled grating spectrograph, and two high-speed cameras with silicon-on-CMOS-multiplexer hybrid focal plane arrays. It will measure the magnetic field strength and direction over the full solar disk within 15 minutes. The Full-Disk Patrol (FDP) takes full-disk solar intensity and Doppler images in various spectral lines and in the continuum at a high cadence through liquid- crystal tuned birefringent filters. The Integrated Sunlight Spectrometer (ISS) uses a fiber-fed spectrograph to measure minute changes of the Sun-as-a-star in many spectral lines. A high degree of automation and remote control provides fast user access to data and flexible interaction with the data-collection process. SOLIS is currently in the final assembly phase and will become operational early in 2003.