Solar Rotation Nos: 2246 to 2247
Overall, there was a decrease in sunspot activity this month. We saw mostly small spots and pores particularly on the 15th when several suddenly popped-up in one day! The exception to this trend was AR2860, which quickly developed into an active extensive sunspot group after it first appeared on the 25th.
There was, however, frequent cloudy weather throughout much of August which impacted observations.
Here are the solar highlights for August 2021 together with a selection of images.
Sunspots
The Sun was spotless on the 1st.
AR2850 appeared on the 2nd near the southwest limb at the high southern latitude of -32°, type Cro. Being close to the limb it disappeared over it on the 6th.
AR2851 came into view near the Central Meridian (CM) on the 6th at +15°, type Bxo, it lasted a single day.
AR2852 appeared near the CM on the 6th at -11°, type Bxo, it too lasted just one day.
The Sun was spotless on the 7th.
AR2853 came over the northeast limb at latitude +23° on the 9th. Short-lived it seems to have just survived until the 16th.
AR2854 came into view on the 12th at -21°. This was a tiny single Axx type spot/pore that had disappeared the following day.
AR2855 was another single Axx spot/pore that appeared on the 12th but on the northern hemisphere at +13°. It disappeared after the 13th.
The Sun was spotless on the 14th.
AR2856 appeared on the 15th at +14°. It went over the west limb around the 17th.
AR2857 also appeared on the 15th at latitude +18°. It disappeared after the 18th.
AR2858 popped into view near the CM at +12° on the 19th. It remained visible until the 23rd.
AR2859 came over the northeast limb on the 22nd at latitude +20°, type Cao, and was minor solar flare active around the 26th. It remained visible up to the end of the month.
AR2860 came over the southeast limb on the 25th at -28°, starting off as a type Bxo initially it increased in size and complexity over the following 2-3 days. By the time it reached the CM on the 28th, it was type Eki, and was multiple solar flare active. It remained visible right up until the end of the month.
AR2861 appeared near the east limb on the 27th at +15° but was gone by the 30th.
AR2862 appeared near the southwest limb at -28° on the 28th, it had disappeared by the 30th.
SPA Sunspot Mean Daily Frequency: 0.80 (was 1.95)
Relative Sunspot Number: 12.68 (was 27.17)
Solar Prominences, Plage, Filaments and Flares
Several small prominences were seen throughout the month with two exceptions.
A tall extensive hedgerow type prominence was seen on the northeast limb on the 14th. It persisted quite a long time right up until the 16th though becoming quite a bit smaller by then.
Another extensive hedgerow prominence was seen on the west limb on the 28th.
Filaments were frequent on the southern hemisphere throughout the month. Some were long and elaborate in nature.
Bright plage were seen around most of the sunspots though some plage were seen in isolation too. Widespread plage were visible with AR2859 and AR2860 towards the end of the month.
SPA Prominence Mean Daily Frequency: 3.33 (was 2.36)
Congratulations to Alan Heath who observed 26 days and to Michael Fullerton who observed 24 days and Jonathan Shanklin on 23 days.
Detailed count records of Active Regions and Relative Sunspot Numbers came from: John Chapman-Smith, Michael Fullerton, Alan Heath, Ian Lee, Lee Macdonald, Jonathan Shanklin, Brendan Shaw and Bob Steele.
Images and drawings were supplied by: Carl Bowron, John Fathers, Ian Lee and Cliff Meredith.
Geoff Elston