August 21, 2017, Eclipse Expedition to Salem, Oregon

Jay Pasachoff, Field Memorial Professor of Astronomy, Williams College; Chair, International Astronomical Union's Working Group on Solar Eclipses

I have observed sixty-four solar eclipses as of the end of 2016, with the sixty-fifth in Argentina in early 2017, and for my sixty-sixth solar eclipse I led a scientific expedition to Salem, Oregon, on August 21, 2017. Preparation for the 2017 eclipse began three years prior to the event, with site visits. Some of the key factors in choosing a site appropriate for viewing an eclipse are cloudiness statistics. Meteorologist Jay Anderson has compiled cloudiness statistics from decades of space observations; see My students and I study the dynamics of the solar corona, how the solar corona varies over the eleven-year sunspot cycle, and how it is heated to millions of degrees. To that end, we will have a variety of imaging cameras with long telephoto lenses as well as spectrographs at the 2017 eclipse. These are common tools for our eclipse expeditions. We used similar instruments at total solar eclipses in Siberia in 2009, in China in 2010, in Easter Island in 2012, in Gabon in 2013, in Svalbard in 2015 and in Indonesia in 2016.

In the photograph [below], the pink-tinted chromosphere glows in hydrogen light, and the pearly white solar corona reflects and scatters sunlight toward us; a rose-colored prominence erupts, and two coronal mass ejections are also visible. Amazingly, this scientific imaging, even with all of the computer processing, gives a similar result and level of detail as Butler painted nearly a century ago.

A composite of several dozen images taken during the 2013 total solar eclipse, viewed from Gabon by Jay Pasachoff; his student Allen Davis, Williams College Class of 2014 (now at Yale University); and his colleague Vojtech Rušin from Slovakia; and processed by Miloslav Druckmüller, Technical University of Brno, Czech RepublicHoward Russell Butler, Solar Eclipse 1925, Princeton University, gift of H. Russell Butler Jr. (PP352)

Images from other eclipse expeditions:

Two photos from our expedition to Svalbard in 2015; credit: Jay M. Pasachoff (Williams College) and Ronald Dantowitz (Clay Center Observatory, Dexter Southfield School)

credit: Michael Zeiler,

Learn more about the 2017 Eclipse:

2017 Eclipse News Coverage

See Bibilography