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There are three instruments aboard the SDO: The Atmospheric Imaging Assembly (AIA), the Helioseismic and Magnetic Imager (HMI) and the Extreme Ultraviolet Variability Experiment (EVE). HMI and AIA were both built by Lockheed Martin Solar and Astrophysics Laboratory (LMSAL) and feature six CCD sensors from e2v (Chelmsford, UK). EVE will measure fluctuations in the sun’s ultraviolet output; HMI will map solar magnetic fields and look beneath the sun’s opaque surface using a technique called helioseismology; and AIA will photograph the sun’s surface and atmosphere at IMAX quality every 10 seconds. Previous observatories have taken pictures, at best, every few minutes with much inferior resolution.

HMI looks beneath the surface at what’s called the solar dynamo, a network of deep plasma currents that generates the sun’s explosive magnetic field. The dynamo is beneath 140,000 miles of overlying hot gas. SDO penetrates that with a form of seismology. Solar physicists use acoustic waves generated by the sun’s own turbulence. The HMI detects the waves, which researchers on earth transform in pictures.

EVE will observe the sun at wavelengths where it is most variable—the extreme ultraviolet (EUV). EUV photos are high-energy cousins of regular UV rays that cause sunburn (our atmosphere blocks solar EUV). In space, however, solar EUV emission is easy to detect and a sensitive indicator of solar activity. EVE will reveal how fast the sun can change.

Four specially processed back illuminated e2v CCD203-82 (4k x 4k) sensors sensitive to extreme UV wavelengths are incorporated into the four AIA telescopes which will observe the Sun in wavelength range of 9.4nm to 170nm. In total, the AIA filters will produce a high-definition image of the sun in eight selected wavelengths out of the 10 available every 10 seconds to reveal key aspects of solar activity. The bands include nine ultraviolet and extreme UV bands and one visible light band. These telescopes will provide the bulk of SDO’s data stream. The AIA instrument is under the direction of Dr. Alan Title at LMSAL, and will use solar images taken in multiple wavelengths to study the energetics of the solar atmosphere and it’s interaction with the surface magnetic fields.

Two front-illuminated e2v CCD203-82 (4k x 4k) sensors are used in the HMI instrument to image the Sun in visible light at 617nm. The HMI instrument (built by LMSAL) is under the direction of Prof. Philip Scherrer at Stanford University (Palo Alto, Calif.), and will measure both solar surface magnetic fields and the Sun’s surface motion as a probe of the solar interior.