Fig. 1. Change in the number of white vapor, red vapor, and black spots (vertical) during 517–975 CE (horizontal axis). The bars in /blue /and/red/ represent the number of candidates of white and red aurora, respectively. The /black dots/ are for the total number of aurora candidates. Note that records of sunspot and aurora candidate are from documents written in different era, therefore colors of background in this figure are used depending on era. (Color online) From: Records of sunspot and aurora activity during 581–959 CE in Chinese official histories concerning the periods of Suí, Táng, and the Five Dynasties and Ten Kingdoms Publ Astron Soc Jpn Nihon Tenmon Gakkai. 2017;69(2). doi:10.1093/pasj/psw132 Publ Astron Soc Jpn Nihon Tenmon Gakkai | © The Author 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved. For Permissions, please email: journals.permissions@oup.com
Fig. 2. Time evolution of geomagnetic latitude at Kāifēng (black) and Cháng’ān (glay) The error bars of one standard deviation as indicated by dotted lines, are evaluated by bootstrap method. From: Records of sunspot and aurora activity during 581–959 CE in Chinese official histories concerning the periods of Suí, Táng, and the Five Dynasties and Ten Kingdoms Publ Astron Soc Jpn Nihon Tenmon Gakkai. 2017;69(2). doi:10.1093/pasj/psw132 Publ Astron Soc Jpn Nihon Tenmon Gakkai | © The Author 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved. For Permissions, please email: journals.permissions@oup.com
Fig. 3. Conuts of auroral candidates against observed month in Tang term. This histogram is laveled with the reported color. From: Records of sunspot and aurora activity during 581–959 CE in Chinese official histories concerning the periods of Suí, Táng, and the Five Dynasties and Ten Kingdoms Publ Astron Soc Jpn Nihon Tenmon Gakkai. 2017;69(2). doi:10.1093/pasj/psw132 Publ Astron Soc Jpn Nihon Tenmon Gakkai | © The Author 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved. For Permissions, please email: journals.permissions@oup.com
Fig. 4. Conuts of auroral candidates against observed month in Tang term. This histogram is laveled with the reported expression; 氣 (vaper: V), 光 (light: L), 雲 (cloud: C), 虹 (rainbow), and so on. From: Records of sunspot and aurora activity during 581–959 CE in Chinese official histories concerning the periods of Suí, Táng, and the Five Dynasties and Ten Kingdoms Publ Astron Soc Jpn Nihon Tenmon Gakkai. 2017;69(2). doi:10.1093/pasj/psw132 Publ Astron Soc Jpn Nihon Tenmon Gakkai | © The Author 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved. For Permissions, please email: journals.permissions@oup.com
Fig. 5. Counts of aurora candidates against moon luminosity Fig. 5. Counts of aurora candidates against moon luminosity. This histogram is labeled with the reported color of vapor. The alphabetic labels represent the color of vapor as W (white), R (red), and all else (blue white). From: Records of sunspot and aurora activity during 581–959 CE in Chinese official histories concerning the periods of Suí, Táng, and the Five Dynasties and Ten Kingdoms Publ Astron Soc Jpn Nihon Tenmon Gakkai. 2017;69(2). doi:10.1093/pasj/psw132 Publ Astron Soc Jpn Nihon Tenmon Gakkai | © The Author 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved. For Permissions, please email: journals.permissions@oup.com
Fig. 6. Records of sunspot (black lines) compared with solar activity from Steinhilber, Beer, and Fröhlich (2009). (Color online) From: Records of sunspot and aurora activity during 581–959 CE in Chinese official histories concerning the periods of Suí, Táng, and the Five Dynasties and Ten Kingdoms Publ Astron Soc Jpn Nihon Tenmon Gakkai. 2017;69(2). doi:10.1093/pasj/psw132 Publ Astron Soc Jpn Nihon Tenmon Gakkai | © The Author 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved. For Permissions, please email: journals.permissions@oup.com
Fig. 7. Records of aurora candidates (black lines) compared with solar activity from Steinhilber, Beer, and Fröhlich (2009). (Color online) From: Records of sunspot and aurora activity during 581–959 CE in Chinese official histories concerning the periods of Suí, Táng, and the Five Dynasties and Ten Kingdoms Publ Astron Soc Jpn Nihon Tenmon Gakkai. 2017;69(2). doi:10.1093/pasj/psw132 Publ Astron Soc Jpn Nihon Tenmon Gakkai | © The Author 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved. For Permissions, please email: journals.permissions@oup.com