Solar Observations: August 2021
By Monty Leventhal OAM
Summing up, sunspot activity for solar cycle 25 has remained very low with Prominences & Filaments remaining quite faint. Flares on my watch have been virtually non existence though some observers in the northern hemisphere saw a few M class Flares, I only saw one.
The most Sunspots seen on one day was on the 28th with 3 groups which included 2 single spots, one with Penumbra and one without. The third group had 18 spots.
For the month of August I made 27 daily observations. The remaining 4 days were cloud covered or raining.
The relevant sunspot number for the month was 11 and the average CV number was 10.6.
My forecast for the month of September is a slight increase in Sunspot activity and a steady increase in Prominences.
On the 1st August the solar disc was clear of sunspots showing that cycle 25 is still at its minimum of activity.
Two of five Prominences were active while the others are quiet. The active one on the NW limb reached a height of about 65,000km. The following day a new Dsi group of spots appeared in the SW in AR12850. On the NE limb a column type Prominence reached a height of about 93,000km as pictured below.
From the 4th August no further Sunspots were seen on the solar disc though almost every day faint Prominences could be seen similar to the one on the 13th which was active, reaching a height of approximately 51,000km.
On the 14th the active Prominence on the NE limb grew to 84,000km high.
In the NE quadrant a new single Axx spot was seen at a latitude of +17° & longitude of 173° It was given a AR number of 12857. Though Sunspot activity remained very low on the 15th a new Bxo group appeared in AR 12857 consisting of 2 very small spots.
How-ever on the NE limb of the Sun the active Prominence seen the day before had grow much larger to a height of 130,000km. It spread across the limb for 233,000km.By the 16th the Prominence on the NE limb remained very active & now reached a height of approximately 140,000km & stretched across the limb for about 251,000km.
On the 17th the same Prominence appeared much fainter. As the Sun rotates from east to west I expected to see a Filament to appear on the Solar disk. This did not occur; perhaps the magnetic fields were too weak.
A Filament would show up as a thin black line as Plasma is forced up in sheet form due to strong N and S polarities through the Chromosphere.
Until the 25th Sunspot activity remained very low but in AR12860 a new group of Dki spots appeared showing some Plage activity.
The following day the 26th the group of spots in AR12860 grew to a CV of Dso (25) and produced a small type one N Flare. It started at 23.15 hrs. UT, peaked at 23.35 and ended at 23.45. It produced an X-ray Flare of M8.
By the 28th the group in AR12860 grew to a classification of Esi (29) which produced more Flares but unfortunately not during my watch. A new single Axx spot was observed in what I believed was AR12863 but was not confirmed.
Though on the 31st Sunspot activity declined once again with AR12860 group reduced to a Dsi (28). Flares became much more active, the largest reaching about 93,000km high.