Total Solar Eclipse 2017

Amir Caspi and Constantine Tsang of the Southwest Research Institute in Boulder, Colorado, will use the DyNAMITE visible and infrared telescopes on NASA’s twin WB-57 airplanes to get a unique look at both the sun and Mercury during the total solar eclipse.

Padma Yanamandra-Fisher of the Space Science Insitute in Rancho Cucamonga, California, will lead an effort to take images of part of the sun’s atmosphere, the solar inner corona – visible only during total solar eclipses – in polarized light. Light becomes polarized as it passes through some kind of medium. The experiment will map the two-dimensional electron distribution in the inner solar corona, which will provide input for models that address the question of why the sun’s atmosphere, the corona, is so much hotter than its surface. The experiment, PACA_PolNet, builds on the work of a citizen science project known as Citizen CATE and will be conducted from two sites: Tetonia, Idaho and Carbondale, Illinois.

Shadia Habbal of the University of Hawaii’s Institute for Astronomy in Honolulu will lead a team of scientists to image the sun from four different states during the total solar eclipse. They will use spectrometers, which analyze the light emitted from different ionized elements in the corona.

During the eclipse, a team of scientists led by Paul Bryans at the National Corporation for Atmospheric Research will sit inside a trailer in Camp Wyoba atop Casper Mountain in Wyoming, and point a specialized instrument at the sun. The instrument is a spectrometer, which collects light from the sun and separates each wavelength of light, measuring their intensity. This particular spectrometer, called the NCAR Airborne Interferometer, will for the first time survey infrared light emitted by the sun’s atmosphere, or corona. Such an experiment can only be conducted from the ground during an eclipse, when the sun’s bright face is blocked, revealing the much fainter corona.

The main goal of this 3-year project is to enable a unique observational campaign during the 21 August 2017 total solar eclipse across the North America. The eclipse observations are unique because they provide a rare opportunity to discover new types of solar phenomena that may be linked to the solar cycle and space weather. The project's high-resolution studies of flaring and active regions at long radio wavelengths should provide information that is potentially useful for space weather predictions.

Radio wave transmissions sent from Lamoure, North Dakota, will be monitored at receiving stations across the eclipse path in Colorado and Utah. The data will be compared with several space-based missions, such as NOAA’s Geostationary Operational Environmental Satellite, NASA’s Solar Dynamics Observatory and NASA’s Ramaty High Energy Solar Spectroscopic Imager, to precisely characterize the effect of the sun’s radiation on the ionosphere.

The ionosphere, an electrically charged outer shell of Earth’s atmosphere, is affected by processes in deeper levels of the atmosphere, as well as by incoming sunlight and particles. Electrons and atoms in the region are constantly being shaken by travelling ionospheric disturbances, which move in ripples through the charged gas, ionized by the sun’s ultraviolet light. These disturbances in the ionosphere are often caused by a phenomenon known as atmospheric gravity waves, which can be triggered by eclipses. A team, led by Phil Erickson of MIT’s Haystack Observatory in Westford, Massachusetts, will use an extended network of sensors to monitor the ionosphere as it crosses America, in order to understand the large-scale effects of these disturbances. Using over 6,000 ground-based sensors along with data from NASA’s space-based Thermosphere Ionosphere Mesosphere Energetics and Dynamics, or TIMED, mission, the team will monitor the changes in the ionosphere in real-time. The data will be publicly available during the eclipse and available online afterwards.

No sensitive spectral survey of the line spectrum of the solar corona has been made beyond 1.6 microns. Previous work indicates the presence of forbidden transitions in coronal ions from 2 to 10 or even 20 microns. Such lines, if sufficiently bright, can be used to diagnose magnetic fields in coronal plasma using new telescopes such as the ATST, scheduled for commissioning in 2019. A spectral survey will also reveal permitted transitions from cool plasma (e.g. prominences) present at coronal heights, also of significant diagnostic interest. Measurements of magnetic fields above the Sun's surface are badly needed to understand the origins of solar activity and terrestrial influences. We argue that the 21 August 2017 eclipse over the mainland USA presents an almost ideal opportunity to perform such a spectral survey. Further, we suggest that the NCAR HIAPER aircraft, when equipped with a modest suite of instruments, is a ready-made platform from which to conduct several cutting-edge experiments. HIAPER can accomodate several experiments through the infrared and optical ports in the top of the fuselage. Fourier transform spectrometers routinely used at ACD, NCAR can readily be augmented to obtain the needed IR spectra.

In Madras, Oregon, a team of NASA scientists led by Nat Gopalswamy at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will point a new, specialized polarization camera at the sun’s faint outer atmosphere, the corona, taking several-second exposures of the sun at four selected wavelengths in just over two minutes. Their images will capture data on the temperature and speed of solar material in the corona. Currently these measurements can only be obtained from Earth-based observations during a total solar eclipse.

Earle and his team will be stationed across the United States in Bend, Oregon, Holton, Kansas, and at the Shaw Air Force Base in Sumter, South Carolina, using custom designed ionosodes, instruments that use radio waves to look up into the ionosphere and measure its height and density. Their measurements will be combined with data from a nation-wide network of GPS receivers and signals from the Ham Radio Reverse Beacon Network, both of which are sensitive to the state of the ionosphere. The team will also utilize data from Virginia Tech’s SuperDARN radars, two of which have been placed along the eclipse path in Christmas Valley, Oregon, and Hays, Kansas. By combining all the data, Earle and his team will be able to improve models of the ionosphere and understand what affect the eclipse had on the region.