During the acquisition of this image, sunspot AR2673 (below and to right of centre) was growing to more than ten times its original size during the course of only 24 hours. It quickly became one of the largest sunspots of 2017.
The Sun's diameter is 109 x Earth's diameter. The largest sunspot on the image is three times Earth's diameter.
Date: 3 September 2017, 13:30 GMT
Telescope: Skywatcher Esprit ED 120
Mount: Astrosysteme Austria ASA DDM160
Solar filter: Thousand Oaks Type 2+, 90 mm diameter
Camera: Lumenera SKYnyx2-2M
Exposure: 11 ms
Number of images in stack = 35 of 200