A <a href="https://en.wikipedia.org/wiki/Sunspot" id="mwFA" rel="mw:WikiLink" title="Sunspot">sunspot</a> is <a href="https://en.wikipedia.org/wiki/Science_and_technology_of_the_Han_dynasty#Astronomical_observations" id="mwFQ" rel="mw:WikiLink" title="Science and technology of the Han dynasty">observed</a> by <a href="https://en.wikipedia.org/wiki/Han_dynasty" id="mwFg" rel="mw:WikiLink" title="Han dynasty">Han dynasty</a> <a href="https://en.wikipedia.org/wiki/Chinese_astronomy" id="mwFw" rel="mw:WikiLink" title="Chinese astronomy">astronomers</a> during the reign of <a href="https://en.wikipedia.org/wiki/Emperor_Cheng_of_Han" id="mwGA" rel="mw:WikiLink" title="Emperor Cheng of Han">Emperor Cheng of Han</a>, one of the earliest dated sunspot observations in China.<sup about="#mwt19" class="mw-ref reference" data-mw='{"name":"ref","attrs":{},"body":{"id":"mw-reference-text-cite_note-1"}}' id="cite_ref-1" rel="dc:references" typeof="mw:Extension/ref"><a href="./May_10#cite_note-1" id="mwGQ" style="counter-reset: mw-Ref 1;"><span class="mw-reflink-text" id="mwGg">[1]</span></a></sup>
<span class="mw-reference-text" id="mw-reference-text-cite_note-1"><cite about="#mwt16" class="citation book cs1" id="CITEREFXuPankenierJiang2000">Xu, Zhenoao; Pankenier, W.; Jiang, Yaotiao (2000). <a class="external text" href="https://books.google.com/books?id=9JatFvikiwQC" id="mwBhY" rel="mw:ExtLink nofollow"><i id="mwBhc">East-Asian Archaeoastronomy: Historical Records of Astronomical Observations of China, Japan and Korea</i></a>. Amsterdam: Gordon and Beach Science Publishers. p.<span id="mwBhg" typeof="mw:Entity"> </span>148. <a class="mw-redirect" href="./ISBN_(identifier)" id="mwBhk" rel="mw:WikiLink" title="ISBN (identifier)">ISBN</a><span id="mwBho" typeof="mw:Entity"> </span><a href="./Special:BookSources/905699302X" id="mwBhs" rel="mw:WikiLink" title="Special:BookSources/905699302X"><bdi id="mwBhw">905699302X</bdi></a>.</cite><span about="#mwt16" class="Z3988" id="mwBh0" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=East-Asian+Archaeoastronomy%3A+Historical+Records+of+Astronomical+Observations+of+China%2C+Japan+and+Korea&amp;rft.place=Amsterdam&amp;rft.pages=148&amp;rft.pub=Gordon+and+Beach+Science+Publishers&amp;rft.date=2000&amp;rft.isbn=905699302X&amp;rft.aulast=Xu&amp;rft.aufirst=Zhenoao&amp;rft.au=Pankenier%2C+W.&amp;rft.au=Jiang%2C+Yaotiao&amp;rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D9JatFvikiwQC&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMay+10"></span></span>