Last month ( February) solar observers had a real treat observing the largest Sunspot group of the current solar cycle No25 .

Peter Meadows of the BAA Solar section wrote

“In addition to producing 3 X-flares over the last day or so, sunspot group AR 13590 is also the largest of this cycle so far. Today (23rd Feb) it reached an area of 1800 millionths of the Sun’s visible hemisphere (MSH). It is an easy naked eye sunspot (using suitable eye protection such as eclipse glasses). It addition it is now ideally placed on the solar disk as it will approach the central meridian in a couple of days. Weather permitting it will be on the solar disk for another week or so.

AR 13590 could become the first Great sunspot group of this cycle (The term great sunspot group generally refers to a group with a mean area for the solar disk-passage greater than or equal to 1500 MSH [1]. This size is about three times larger than of a sunspot that is just visible with the protected naked eye. “

Above is a video sequence showing the development of the spot AR1359 between the 18th and 28th of February. This sequence was generated in ‘ESA JHelioviewer’ software which is available to download from ESA’s website here https://www.jhelioviewer.org/

One of our members Nigel price managed to image the Sun the following day

Nigel used his modified PST single stacked Etalon which is a 40mm aperture f/10, using a ZWO ASI678MC camera. Bias and flat frames were subtracted in Sharpcap at 42 frames per second – this only takes 12 seconds! The resulting video file was processed in Autostakkert3. The best 25% frames of that video were then stacked and processed in imppg image enhancing software.

If you want to see how Nigel processes his Solar images, why not come along to our 7, March 2024 meeting and find out.