A solar telescope that captures images of the entire disk of the Sun, monitoring eruptions taking place simultaneously in different magnetic fields in both the photosphere and chromosphere, is now being installed beside the Goode Solar Telescope (GST) at NJIT’s California-based Big Bear Solar Observatory (BBSO).
The telescope, SOLIS (Synoptic Optical Long-term Investigations of the Sun), collects images from three separate instruments over years and even decades, rather than minutes or hours, giving scientists a comprehensive view of solar activity such as flares and coronal mass injections over the long-term. It will complement the GST, which gathers high-resolution images of individual explosions at such detail that researchers are beginning to unveil the mechanical operations that trigger them.
“With this important addition, BBSO becomes a comprehensive observing site that offers not only high-resolution solar observations, but also global data of our star,” notes Wenda Cao, an NJIT professor of physics and BBSO’s director. “By monitoring variations in the Sun on a continuing basis for several decades, we will better understand the solar activity cycle, sudden energy releases in the solar atmosphere, fluxes in solar irradiance, or brightness, and their relationship to global change on Earth.”
Earlier this month, BBSO received a $2.3 million grant from the National Science Foundation (NSF) that will fund continuing scientific study of the Sun using the 1.6-meter GST at Big Bear, which is currently the highest resolution solar telescope in the world.
“GST will continue to play a crucial, leading role in advancing solar studies until the end of this decade and beyond. We will obtain, analyze and interpret the highest resolution solar data ever taken, while developing and applying analytical tools to attack a number of critical, leading-edge problems in solar research,” says Cao, the grant’s principal investigator.
Big Bear Lake is an ideal location, because the lake minimizes atmospheric turbulence caused by heating thermals, offering exceptional “seeing” for long periods per day on its more than 286 sunny days per year.
SOLIS is a suite of three innovative instruments that greatly improve ground-based synoptic solar observations. The 50-cm vector spectromagnetograph 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.
“SOLIS continues a 45-year record of data on the behavior of the Sun’s magnetic field that originally began at Kitt Peak, Arizona. It is also the longest consistent provider of data on the direction of the magnetic field in the photosphere, stretching back to 2003.” says Frank Hill, associate director of the NSO.
Earlier this year, a team of physicists led by NJIT’s Gregory Fleishman discovered a phenomenon that may begin to untangle what they call “one of the greatest challenges for solar modeling”—determining the physical mechanisms that heat the corona, or upper atmosphere, to 1 million degrees Fahrenheit and higher.
Invisible to the human eye except when it appears briefly as a fiery halo of plasma during a solar eclipse, the corona remains a puzzle even to scientists who study it closely. Beginning 1,300 miles from the star’s surface and extending millions more in every direction, it is more than a hundred times hotter than lower layers much closer to the fusion reactor at the Sun’s core.