Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Heliophysics at total solar eclipses

Nature Astronomy volume 1, Article number: 0190 (2017) Cite this article

Subjects

Abstract

Observations during total solar eclipses have revealed many secrets about the solar corona, from its discovery in the 17th century to the measurement of its million-kelvin temperature in the 19th and 20th centuries, to details about its dynamics and its role in the solar-activity cycle in the 21st century. Today's heliophysicists benefit from continued instrumental and theoretical advances, but a solar eclipse still provides a unique occasion to study coronal science. In fact, the region of the corona best observed from the ground at total solar eclipses is not available for view from any space coronagraphs. In addition, eclipse views boast of much higher quality than those obtained with ground-based coronagraphs. On 21 August 2017, the first total solar eclipse visible solely from what is now United States territory since long before George Washington's presidency will occur. This event, which will cross coast-to-coast for the first time in 99 years, will provide an opportunity not only for massive expeditions with state-of-the-art ground-based equipment, but also for observations from aloft in aeroplanes and balloons. This set of eclipse observations will again complement space observations, this time near the minimum of the solar activity cycle. This review explores the past decade of solar eclipse studies, including advances in our understanding of the corona and its coronal mass ejections as well as terrestrial effects. We also discuss some additional bonus effects of eclipse observations, such as recreating the original verification of the general theory of relativity.

The solar corona, normally too faint to be seen with the naked eye but revealed during total solar eclipses, has been known since at least its description by Kepler in 16051, though he thought it could be a lunar atmosphere. The discovery of emission lines in the spectrum observed during the eclipse of 1868, attributed to helium2, and during the eclipse of 1869 (attributed to a new element called coronium)3 led to the discovery of the high temperature of the corona. In the 1940s, W. Grotrian, B. Edlén and H. Alfvén4 found that the supposed coronium is actually highly ionized iron gas at temperatures of about a million kelvin. Starting with the strong solar storm in 1859 — the Carrington event — scientists have known about the ‘space weather’ that permeates what is now known as the ‘heliosphere’ and affects us on Earth as well as the satellites around us. Even the discovery of thousands of comets with a camera on ESA's SOlar and Heliospheric Observatory (SOHO) has led to an increased appreciation of the changing environment near the Sun and its link to objects from farther out in the heliosphere. NASA's plan to launch the Parker Solar Probe in 2018 to travel to within 6 million km of the solar surface (about 4% of an astronomical unit from the Sun) will reveal in situ measurements of that portion of the heliosphere, a region crucial to the development of space weather. Overlapping observations of the total solar eclipses of 2019 and 2020 with the spacecraft's observations should allow improved mutual calibration.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Get just this article for as long as you need it

$39.95

Learn more

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Stereographic map of the 21 August 2017 eclipse.
Figure 2: The most recent total solar eclipse, photographed from Ternate, Indonesia, in 2016.
Figure 3: The 2013 total solar eclipse, observed from Gabon.

© 2013 JAY PASACHOFF, ALLEN DAVIS, VOJTECH RUSIN / © 2014 MILOSLAV DRUCKMULLER

Figure 4: The paths of total and annular solar eclipses between 2001 and 2025.

References

  1. Kepler, J. Astronomiæ Pars Optica (Apud Claudium Marnium & Hæredes Ioannis Aubrii, 1604).

    MATH  Google Scholar 

  2. Nath, B. The Story of Helium and the Birth of Astrophysics (Springer, 2013).

    Book  Google Scholar 

  3. Golub, L. & Pasachoff, J. M. The Solar Corona 2nd edn (Cambridge Univ. Press, 2010).

    Google Scholar 

  4. Peter, H. & Dwivedi, B. N. Discovery of the Sun's million-degree hot corona. Front. Astron. Space Sci.http://doi.org/b9gk (2014).

  5. Pasachoff, J. M. Solar eclipses as an astrophysical laboratory. Nature 459, 789 (2009).

    Article  ADS  Google Scholar 

  6. Pasachoff, J. M. Scientific observations at solar eclipses. Res. Astron. Astrophys. 9, 613–634 (2009).

    Article  ADS  Google Scholar 

  7. Golub, L. & Pasachoff, J. M. The Sun (Reaktion Press and Univ. Chicago Press, 2017).

    Google Scholar 

  8. Pasachoff, J. M. & Fraknoi, A. Resource letter OSE-1 on observing solar eclipses. Am. J. Phys. 85, 485–494 (2017).

    Article  ADS  Google Scholar 

  9. Pasachoff, J. M. An all-American eclipse. Nature 545, 409–410 (2017).

    Article  ADS  Google Scholar 

  10. Pasachoff, J. M. & Olson, R. J. M. Art of the eclipse. Nature 506, 314–315 (2014).

    Article  ADS  Google Scholar 

  11. Pasachoff, J. M. et al. The 2008 August 1 eclipse solar-minimum corona unraveled. Astrophys. J. 702, 1297–1308 (2009).

    Article  ADS  Google Scholar 

  12. Pasachoff, J. M. et al. Structure and dynamics of the 11 July 2010 eclipse white-light corona, Astrophys. J. 734, 114–124 (2011).

    Article  ADS  Google Scholar 

  13. Pasachoff, J. M. et al. Structure and dynamics of the 2012 November 13/14 eclipse white-light corona. Astrophys. J. 800, 90–109 (2015).

    Article  ADS  Google Scholar 

  14. Hanaoka, Y. et al. Coronal mass ejections observed at the total solar eclipse on 13 November 2012. Solar Phys. 289, 2587–2599 (2014).

    Article  ADS  Google Scholar 

  15. Pasachoff, J. M., Rušin, V. Saniga, M., Davis, A. B. & Seaton, D. B. Intricacies of the 2013 November hybrid-eclipse white-light corona. Preprint at http://sites.williams.edu/eclipse/2013-gabon/ (2017).

  16. Li, Z., Qu, Z., Yan, X., Dun, G. & Chang, L., Mass motion in upper solar chromosphere detected from solar eclipse observation. Astrophys. Space Sci. 361, 159–169 (2016).

    Article  ADS  Google Scholar 

  17. Pasachoff, J. M. & Carter, A. L. The solar corona at the 2015 total solar eclipse. Triennial Earth–Sun Summit (TESS) of the AAS and AGU 203.19 (2015).

  18. Pasachoff, J. M., Seaton, D. B. & Sterling, A. C. Early evaluation of the corona at the 2016 March 9 total solar eclipse. Am. Astron. Soc. Solar Phys. Div. 3.26 (2016).

  19. Pasachoff, J. M. First report on the 2016 March 9 total solar eclipse observations. Am. Astron. Soc. 311.05 (2016).

  20. http://www.zam.fme.vutbr.cz/∼druck/eclipse/

  21. Druckmüller, M., Habbal, S. R. & Morgan, H. Discovery of a new class of coronal structures in white light eclipse images. Astrophys. J. 785, 14–21 (2014).

    Article  ADS  Google Scholar 

  22. Habbal, S. R., Morgan, H. & Druckmüller, M. Exploring the prominence-corona connection and its expansion into the outer corona using total solar eclipse observations. Astrophys. J. 793, 119–137 (2014).

    Article  ADS  Google Scholar 

  23. Habbal, S. R. et al. Mapping the distribution of electron temperature and Fe charge states in the corona with total solar eclipse observations. Astrophys. J. 708, 1650–1662 (2010).

    Article  ADS  Google Scholar 

  24. Habbal, S. R., Morgan, H., Druckmüller, M. & Ding, A. On the constancy of the electron temperature in the expanding corona throughout solar cycle 23. Astrophys. J. Lett. 711, L75–L78 (2010).

    Article  ADS  Google Scholar 

  25. Habbal, S. R. et al. Total solar eclipse observations of hot prominence shrouds. Astrophys. J. 719, 1362–1369 (2010).

    Article  ADS  Google Scholar 

  26. Habbal, S. R. et al. Thermodynamics of the solar corona and evolution of the solar magnetic field as inferred from the total solar eclipse observations of 2010 July 11. Astrophys. J. 734, 120–138 (2011).

    Article  ADS  Google Scholar 

  27. Druckmüllerová, H., Morgan, H. & Habbal, S. R. Enhancing coronal structures with the Fourier normalizing-radial-graded filter. Astrophys. J. 737, 88–98 (2011).

    Article  ADS  Google Scholar 

  28. Habbal, S. R. et al. Probing the fundamental physics of the solar corona with lunar solar occultation observations. Solar Phys. 285, 9–24 (2013).

    Article  ADS  Google Scholar 

  29. Ding, A. & Habbal, S. R. First detection of prominence material embedded within a 2 × 106 K CME front streaming away at 100–1500 km s−1 in the solar corona. Astrophys. J. 842, L7–L15 (2017).

    Article  ADS  Google Scholar 

  30. Raju, K. P., Chandrasekhar, T. & Ashok, N. M. Analysis of coronal green line profiles: evidence of excess blueshifts. Astrophys. J. 736, 164–171 (2011).

    Article  ADS  Google Scholar 

  31. Singh, J. et al. Intensity oscillation in the corona as observed during the total solar eclipse of 29 March 2006. Solar Phys. 260, 125–134 (2009).

    Article  ADS  Google Scholar 

  32. Singh, J., Hasan, S. S., Gupta, G. R., Nagaraju, K. & Banerjee, D. Spectroscopic observation of oscillations in the corona during the total solar eclipse of 22 July 2009. Solar Phys. 270, 213–233 (2011).

    Article  ADS  Google Scholar 

  33. Samanta, T., Singh, J., Sindhuja, G. & Banerjee, D. Detection of high-frequency oscillations and damping from multi-slit spectroscopic observations of the corona. Solar Phys. 291, 155–174 (2016).

    Article  ADS  Google Scholar 

  34. Pasachoff, J. M. The great solar eclipse of 2017. Sci. Am. 317, 54–61 (2017).

    Article  Google Scholar 

  35. Hanaoka, Y., Kikuta, Y., Nakazawa, J., Ohnishi, K. & Shiota, K. Accurate measurements of the brightness of the white-light corona at the total solar eclipses on 1 August 2008 and 22 July 2009. Solar Phys. 279, 75–89 (2012).

    Article  ADS  Google Scholar 

  36. Hansky. A . Total solar eclipse on the 9th of August 1896. Bull. Acad. Imperial Sci. St. Petersburg 6, 251–256 (1897).

    Google Scholar 

  37. Rušin, V. The flattening index of the eclipse white-light corona and magnetic fields. Solar Phys. 292, 24–33 (2017).

    Article  ADS  Google Scholar 

  38. Rušin, V., Saniga, M. & Komzík, R. White-light corona and solar polar magnetic field strength over solar cycles. Contrib. Astron. Obs. Skalnaté Pleso 44, 119–129 (2014).

    ADS  Google Scholar 

  39. Menzel, D. H. & Pasachoff, J. M. The outer corona at the eclipse of 7 March 1970. Nature 226, 1143–1144 (1970).

    Article  ADS  Google Scholar 

  40. Pasachoff, J. M. & Suer, T.-A. The origin and diffusion of the H and K notation. J. Astron. Hist. Heritage 13, 120–126 (2010).

    ADS  Google Scholar 

  41. Skomorovsky, V. I. et al. White-light observations and polarimetric analysis of the solar corona during the eclipse of 1 August 2008. Solar Phys. 277, 267–281 (2012).

    Article  ADS  Google Scholar 

  42. Kim, I. S., Nasonova, L. P., Lisin, D. V., Popov, V. V. & Krusanova, N. L. Imaging the structure of the low K-corona. J. Geophys. Res. Space Phys. 122, 77–88 (2017).

    Article  ADS  Google Scholar 

  43. Kim, I. S., Alexeeva, I. V., Bugaenko, O. I., Popov, V. V. & Suyunova, E. Z. Near-limb Zeeman and Hanle diagnostics. Solar Phys. 288, 651–661 (2013).

    Article  ADS  Google Scholar 

  44. Kim, I. S., Popov, V. V., Lisin, D. V. & Osokin, A. R. Observations of neutral hydrogen in the corona. Geomagnetism and Aeronomy 53, 901–903 (2013).

    Article  ADS  Google Scholar 

  45. Eclipse 2017: NASA supports a unique opportunity for science in the shadow. NASA (3 February 2017); http://go.nature.com/2s9AN9d

  46. Qu, Z. Q. et al. Prototype FASOT. Astron. Soc. Pacific Conf. Ser. 489, 263–270 (2014).

    ADS  Google Scholar 

  47. Qu, Z. Q. et al. Spectro-imaging polarimetry of the local corona during solar eclipse. Solar Phys. 292, 37–60 (2017).

    Article  ADS  Google Scholar 

  48. Judge, P. G., Habbal, S. & Landi, E. From forbidden coronal lines to meaningful coronal magnetic fields. Solar Phys. 288, 467–480 (2013).

    Article  ADS  Google Scholar 

  49. Voulgaris, A., Athanasiadis, T. M., Seiradakis, J. H. & Pasachoff, J. M. A comparison of the red and green coronal line intensities at the 29 March 2006 and the 1 August 2008 total solar eclipses: considerations of the temperature of the solar corona. Solar Phys. 264, 45–55 (2010).

    Article  ADS  Google Scholar 

  50. Voulgaris, A, Gaintatzis, P., Seiradakis, J. H., Pasachoff, J. M. & Economou, T. E. Spectroscopic coronal observations during the total solar eclipse of 11 July 2010. Solar Phys. 278, 187–202 (2012).

    Article  ADS  Google Scholar 

  51. Koutchmy, S., Contesse, L., Viladrich, Ch., Vilinga, J. & Bocchialini, K. About the Fe XIV 530.3 nm line emissions of the middle corona. Proc. 11th European Solar Phys. Meeting S32, ESA SP-600 (2005).

  52. Takeda, A., Kurokawa, H., Kitai, R. & Ishiura, K. Contribution and properties of the green- and red-line coronal loops in the K-corona. Publ. Astron. Soc. Japan 52, 375–391 (2000).

    Article  ADS  Google Scholar 

  53. Bazin, C. & Koutchmy, S. Helium shells and faint emission lines from slitless flash spectra. J. Adv. Res. 4, 307–313 (2013).

    Article  Google Scholar 

  54. Bazin, C., Koutchmy, S. & Tavabi, E. Prominence cavity regions observed using SWAP 174 Å filtergrams and simultaneous eclipse flash spectra. Solar Phys. 286, 255–270 (2013).

    Article  ADS  Google Scholar 

  55. Harrison, R. G. & Hanna, A. The solar eclipse: a natural meteorological experiment. Phil. Trans. R. Soc. A 374, 20150225 (2016).

    Article  ADS  Google Scholar 

  56. Scott, C. J. et al. Using the ionospheric response to the solar eclipse on 20 March 2015 to detect spatial structure in the solar corona. Phil. Trans. R. Soc. A 374, 20150216 (2016).

    Article  ADS  Google Scholar 

  57. Pasachoff, J. M., Peñaloza-Murillo, M. A., Carter, A. L. & Roman, M. T. Terrestrial atmospheric responses on Svalbard to the 20 March 2015 Arctic total solar eclipse under extreme conditions. Phil. Trans. R. Soc. A 374, 20160188 (2016).

    Article  ADS  Google Scholar 

  58. Sôma, M. & Tanikawa, K. Earth rotation derived from occultation records. Publ. Astron. Soc. Japan 68, 29–37 (2016).

    Article  ADS  Google Scholar 

  59. Stephenson, F. R. Historical Eclipses and Earth's Rotation (Cambridge Univ. Press, 2008).

    MATH  Google Scholar 

  60. Stephenson, F. R., Morrison, L. V. & Hohenkerk, C. Y. Measurement of the Earth's rotation: 720 BC to AD 2015. Proc. R. Soc. A 472, 20160404 (2016).

    Article  ADS  Google Scholar 

  61. Olson, R. J. M. & Pasachoff, J. St. Benedict sees the light: Asam's solar eclipses as a metaphor. Relig. Arts 11, 299–329 (2007).

    Article  Google Scholar 

  62. http://www.artcenter.edu/connect/events/eclipse.html

  63. Blatchford, I. Symbolism and discovery: eclipses in art. Phil. Trans. R. Soc. A 374, 20150211 (2016).

    Article  ADS  Google Scholar 

  64. Galy, C. et al. Design and modelisation of ASPIICS optics. Proc. SPIE 9604, 96040B (2015).

    Article  Google Scholar 

  65. Espenak, F. Thousand Year Canon of Solar Eclipses, 1501 to 2500 (AstroPixels, 2014).

    Google Scholar 

  66. Pasachoff, J. M. Peterson Field Guide to the Stars and Planets 4th edn (Houghton Mifflin Harcourt, 2016).

    Google Scholar 

  67. Pasachoff, J. M. & Filippenko, A. The Cosmos: Astronomy in the New Millennium 4th edn (Cambridge Univ. Press, 2014)

    Google Scholar 

  68. Léna, P. Racing the Moon's Shadow with Concorde 001 (Springer, 2016); http://go.nature.com/2tgPQPR

    Google Scholar 

  69. https://www.nsf.gov/awardsearch/showAward?AWD_ID=1531549

  70. Soma, M. Observations of the annular eclipse on 2012 May 21 by the general public in Japan. Publ. Korean Astron. Soc. 30, 753–755 (2015).

    ADS  Google Scholar 

  71. https://eclipsemega.movie/

  72. https://sites.google.com/site/citizencateexperiment/

  73. Pasachoff, J. M. Visual physics: partial eclipse via cheese grater. Phys. Teacher 55, 320 (2017).

    Article  ADS  Google Scholar 

  74. http://eclipse.montana.edu

  75. http://www.eclipsetours.com/eclipse-edge/2017/

  76. Dunham, D. W., Sofia, S., Guhl, K. & Herald, D. R. Solar diameter measurements from eclipses as a solar variability proxy. International Astronomical Union General Assembly 2257941 (2016).

  77. Raponi, A., Sigismondi, C., Guhl, K., Nugent, R. & Tegtmeier, A. The measurement of solar diameter and limb darkening function with the eclipse observations. Solar Phys. 278, 269–283 (2012).

    Article  ADS  Google Scholar 

  78. Rapodi, A. The Measurement of Solar Diameter and Limb Darkening Function with the Eclipse Observations MSc thesis, Sapienza Università di Roma (2013); https://arxiv.org/pdf/1302.3469.pdf

    Google Scholar 

  79. Lamy, P. et al. A novel technique for measuring the solar radius from eclipse light curves — results for 2010, 2012, 2013, and 2015. Solar Phys. 290, 2617–2648 (2015).

    Article  ADS  Google Scholar 

  80. Wright, E. T. Visualizing the eclipse. US Solar Eclipse 2017 (AAS, 2017); https://aas.org/education/outreach/eclipse-2017

  81. Jubier, X. Solar Eclipse Maestro (2017); http://go.nature.com/2t5t5fZ

    Google Scholar 

  82. Pasachoff, J. M. & Pasachoff, N. This isn’t the 1st eclipse to occur on Aug. 21, and it won’t be the last. Space.com (26 June 2017); http://www.space.com/37305-august-21-eclipses.html

  83. Schaefer, B. E. Systematic problems with the original Eddington experiment of 1919. 230th Am. Astron. Soc. Meeting 119.03 (2017); https://aas.org/files/aas230-abstract-pdf.pdf

  84. Bruns, D. A do-it-yourself relativity test. Sky & Telescope (9 June 2016); http://go.nature.com/2shOnaN

  85. Bruns, D. Measuring starlight deflection during the 2017 eclipse. Proc. 35th Ann. Symp. on Telescope Science 49–57 (2016).

  86. Oswalt, T. D. A centennial gift from Einstein. Science 356, 1015 (2017).

    Article  ADS  Google Scholar 

  87. Sahu, K. C. et al. Relativistic deflection of background starlight measures the mass of a nearby white dwarf star. Science 356, 1046–1050 (2017).

    Article  ADS  Google Scholar 

  88. Espenak, F. & Anderson, J. Eclipse Bulletin: Total Solar Eclipse of 2017 August 21 (AstroPixels, 2015).

    Google Scholar 

  89. http://GreatAmericanEclipse.com

  90. http://go.nature.com/2shJvCs

  91. http://eclipsophile.com

  92. Hurd, D., Runyon, C., Minafra, J. & Hall. C. Getting a Feel for Eclipses (NASA, 2016).

    Google Scholar 

  93. http://eclipse.aas.org/resources/solar-filters

  94. Cottam, S. & Orchiston, W. Eclipses, Transits, and Comets of the Nineteenth Century: How America's Perception of the Skies Changed (Springer, 2014).

    Google Scholar 

Download references

Acknowledgements

I thank S. Koutchmy, Z. Qu, H. Kurokawa, I. Kim, T. Chandrasekhar and J. Singh for information about articles from their respective countries. My research on the 2017 eclipse is supported in large part by grants from the Solar Terrestrial Program of the Atmospheric and Geospace Sciences Division of the US National Science Foundation and from the Committee for Research and Exploration of the National Geographic Society.

Author information

Authors and Affiliations

  1. Hopkins Observatory, Williams College, Williamstown, 01267, Massachusetts, USA

    Jay M. Pasachoff

  2. Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, 91125, California, USA

    Jay M. Pasachoff

Authors
  1. Jay M. Pasachoff
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Jay M. Pasachoff.

Ethics declarations

Competing interests

The author declares no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

M. Pasachoff, J. Heliophysics at total solar eclipses. Nat Astron 1, 0190 (2017). https://doi.org/10.1038/s41550-017-0190

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1038/s41550-017-0190

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing