359 citations
- University of LisbonPT47 papers
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Showing 2013 · astro-ph.SRShow all
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astro-ph.SR2013★ 31 cited
Revised Group Sunspot Number for 1640, 1652, and 1741
J. M. Vaquero, R. M. Trigo
Some studies have shown that our knowledge on solar activity in the years 1640, 1652, and 1741 can be improved. In this contribution, we revise the annual group sunspot numbers for…
astro-ph.SR2013★ 20 cited
Forty two years counting spots: solar observations by D. E. Hadden during 1890-1931 revisited
V. M. S. Carrasco, J. M. Vaquero, M. C. Gallego +1
We have recovered the sunspot observations made by David E. Hadden during 1890-1931 from Alta, Iowa. We have digitized the available data published by Hadden in different astronomi…