We use the clock to study solar and geomagnetic climatology as seen in datasets available over multiple solar cycles. We construct a new solar cycle phase clock which maps each of the last 18 solar cycles onto a single normalized epoch for the approximately 22 year Hale (magnetic polarity) cycle, using the Hilbert transform of daily sunspot numbers (SSN) since 1818. M.: A long-term geophysical and astronomical dataset: sunspot counting from 1610 to 2021, EGU General Assembly 2021, online, 19–, EGU21-15499,, 2021. (2009) The Sun recorded through history (Springer). (2020) Living Reviews in Solar Physics 17, 1.Ĭlette, F. In this work, we try to present the latest advances in this task (Muñoz-Jaramillo and Vaquero, 2019 Arlt and Vaquero, 2020).Īrlt, R., Vaquero, J.M.

(2014).Ĭurrently, research to improve the Sunspot Number is focused on (i) improving the database by reviewing old observations, and (ii) improving the methodologies to convert raw data into the Sunspot Number index. Many of these differences were solved by Clette et al. In 1998, Hoyt and Schatten presented a new reconstruction of solar activity that was very different from Wolf's reconstruction (Vaquero and Vázquez, 2009). The Zurich Observatory (and later the Brussels Observatory) was in charge of continuing Wolf's work to the present day. The first attempt to reconstruct solar activity from these records was made by Rudolf Wolf, who defined the Sunspot Number index in the 19th century. For this reason, it is possible to rescue the ancient observations of sunspots made in the past centuries to obtain an image of the evolution of solar activity during the last four centuries. This task can be done even with small telescopes since the Sun is apparently a very large and luminous star. A very simple measure of solar activity is counting sunspots using telescopes. Solar activity is an essential factor for the study of many aspects of the geophysical and astronomical sciences.

Soltrace academy critical role