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The Sun in 2017

The Sun in 2017 as seen by the CESAR Helios Observatory located at ESAC, Madrid. The posters compile in a calendar form a sample of the images acquired during each day in 2017. The solar activity in this period was low. (Click on posters for higher resolution)

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There are  holes in the daily coverage because of bad weather, maintenance activities or non availability of the operators. This is quite remarkable as the daily consistent operations of the telescopes (except weekends) was only started around April. The number of observations (days) was:


Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total
2017 3 2 4 11 14 25 20 9 16 18 15 13 150






Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total
2017 2 2 4 11 14 25 20 9 15 18 16 13 149




Please note that the Sun is currently in its Cycle 24 (end of) with a discreet average number of sunspots of 22. It is the 24th solar cycle since 1755, when extensive recording of solar sunspot activity began. It began in December 2008 with a smoothed minimum of 2.2 (SIDC formula). There was only minimal activity until early 2010. It reached its maximum in April 2014 with a smoothed sunspot number of only 116.4, the lowest in over a century.


During the year, several powerful plasma eruptions - prominences were captured by the Helios observatory. Some examples are presented below.


Please also note that a special activity was carried out during the Total Solar Eclipse on the 21 August 2017, in Casper, USA. A team from CESAR travelled and observed the event in a live transmission. You can find out more in its preparation web page and the results in the results web page.


Other transiting objects were captured as well, as illustrated in the next images.

Plane crossing, 26 April 2017 ISS crossing, 14 May 2017. Comparison with a Moon crossing on 14th Jan 2017


The Sun's apparent diameter was also measured during 2017, with the following result

Other solar news during 2017:

School visits to ESAC during 2017 related to Sun activities:

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