Solar Rotation Nos: 2249 to 2251
Here are the highlights of solar activity for October and November 2021 together with a selection of images.
Sunspots (October)
A slight decrease in sunspot activity, compared to the previous month, but there was plenty to see this month.
AR2877 first appeared near the CM at -17° on the 27th September. On the 1st October it was seen nearing the west limb of the Sun having developed to type Dao. It went over the west limb by the 4th.
AR2880 appeared over the east limb at +30° on the 29th September. On the 1st October it was seen between the east limb and the Central Meridian (CM) having developed to type Dao. It began to fade by the 6th as it neared the west limb and went over the solar limb by the 8th.
AR2882 came over the east limb on the 4th at +14° and was seen developing to type Cso by the 7th becoming minor solar flare active as it did so. It reached the CM around the 10th, by then type Dho, and produced several minor solar flares. At the time it was the only sunspot visible and was glimpsed with the protected naked eye from the 7th to the 10th. It seemed to fade a little on the 11th before developing slightly again on the 13th. It went over the west limb by the 16th leaving the Sun spotless.
AR2886 came over the east limb around the 19th at -19°. This largely stable sunspot hardly changed at all as it crossed the southern half of the solar disc. It went over the west limb around the 30th.
AR2887 was seen developing as soon as it appeared over the east limb at -24° on the 23rd. It continued to grow to type Dki by the 25th. Unusually, the two main sunspots in this group were both of positive magnetic polarity (it might help to think of a sunspot group as like a large magnet usually one spot is positive ‘+’ while the other is negative ‘-‘). As it approached the west limb on the 30th some decay had started to appear.
AR2891 came over the east limb at +17° on the 27th, type Cao, and minor flare active. It developed rapidly to type Dhi by the 28th, producing many minor solar flares that day and even an X-class flare, it developed further to type Eac by the 31st October.
SPA Sunspot Mean Daily Frequency: 1.74 (was 2.52)
Relative Sunspot Number: 23.81 (was 38.00)
Congratulations to Jonathan Shanklin who observed 27 days and to Alan Heath and to Simon Brown who both achieved 24 days.
Sunspots (November)
An increase in sunspot activity, compared to October.
AR2887 appeared over the east limb at -24° on the 23rd October. On November 1st it was still minor flare active as it approached the west solar limb. It went over the west limb by the 5th.
AR2891 came over the east limb at +17° on the 27th October. On the 3rd November, although it seemed to be slightly decaying, it still produced a minor solar flare. It went over the west limb by the 8th.
AR2894 was solar flare active as soon as it came over the east limb on the 6th at -27°. It did not develop any further as it quietly crossed the solar disc but showed a light bridge (as did AR2893) on the 9th. It disappearing over the west limb by the 18th.
AR2895 came over the east limb on the 8th at +26° and very rapidly developed into a pair of sunspots. Despite the rapid growth it did not develop further and had gone by the 14th.
AR2898 appeared on the disc around the 24th at -24°. It was seen as a fairly active, type Cro, sunspot near the CM on the 27th and remained visible up to the end of the month.
AR2900 popped-up preceding AR2898 on the 27th at -28° also type Cro. It developed overnight to type Dso and was still visible nearing the west limb (along with AR2898) on the last day of November.
SPA Sunspot Mean Daily Frequency: 2.17 (was 1.74)
Relative Sunspot Number: 26.26 (was 23.81)
Solar Prominences, Plage, Filaments and Flares (October)
Numerous prominences were seen around the solar limb on the 1st particularly along the south west and north east limbs. In comparison, the rest of the month was quieter but the 25th came close.
A tall flame-like prominence appeared on the north limb on the 6th.
An extensive, but very faint cloud-like prominence appeared on the east limb on the 15th.
A cloud-like broad arch-type prominence was seen south limb on the 25th.
Bright plage were seen with nearly all the sunspots crossing the solar disc throughout the month, except for AR2886 which had little in the way of plage. AR2880, on the 3rd, and AR2887, on the 25th, seemed to show extensive plage.
There were some separate filaments seen (e.g. not associated with any sunspot Active Regions) especially on the 3rd and the 25th.
SPA Prominence Mean Daily Frequency: 5.87 (was 4.57)
Solar Prominences, Plage, Filaments and Flares (November)
Poor weather had an impact on the number of observations this month.
The 4th saw three closely grouped bright prominences along the west limb (one of these was mountain-like in shape) while nearby a filaprom (a combination of filament and prominence) was also visible.
A spectacular collection of 5 prominences were seen along the east limb on the 25th.
Most of the filaments seen this month seemed to not be associated with any sunspot Active Regions, particularly on the 22nd.
On the 4th a long split ‘Y’-shaped filament and plage were visible at the former site of AR2891.
A scythe-shaped filament appeared near the south limb on the 19th remaining visible in ever-changing form as it crossed the solar disc until it began to near the west limb on the 26th by which time it appeared to broaden out.
SPA Prominence Mean Daily Frequency: 4.14 (was 5.87)
Congratulations to Alan Heath who observed 26 days, to Jonathan Shanklin on 22 days and to Michael Fullerton who achieved 18 days.
Detailed count records of Active Regions and Relative Sunspot Numbers came from: Simon Brown, John Chapman-Smith, Michael Fullerton, Alan Heath, Ian Lee, Lee Macdonald, Jonathan Shanklin, Brendan Shaw and Bob Steele.
Images and drawings were supplied by: Mark Beveridge, Carl Bowron, Paul Brierley, Murray Foster, Mick Jenkins, Ian Lee, Cliff Meredith and Larry Todd.
Wishing you all a Merry Christmas and a Happy New Year!
Geoff Elston