Each month a summary of sunspot activity is written and forms part of a report sent to the Solar Section of the British Astronomical Association (BAA) and to The Astronomer. Follow the links below to read a page summary of sunspot activity. The McIntosh Sunspot Group Classification is used for sunspot group descriptions.

January 2011

On the 4th there were 2 groups, one in each hemisphere – AR 1140 of type Hax & area 150 millionths at 31°N/189° and AR 1142 of type Dso & area 60 millionths at 13°S/208°. AR 1140 was seen again on the 9th of the same type but reduced in size – AR 1142 must have decayed on the disk.  AR 1145 at 17°N/98° of type Bxo was the second group seen on the 9th.

On the 16th a single Hsx sunspot was seen near the eastern limb at 23°N/342° (AR 1147). By the 18th a string of sunspots were seen following the penumbral sunspot to make the group type Cao with an area of 160 millionths. This group was of similar appearance on the 19th but by the 21st several small penumbral sunspots had developed just to the south at 18°N/344° (AR 1149).  By the following day, the 22nd, AR 1147 had decayed back to a single Hsx sunspot while AR 1149 had become type Csi with an area of 60 millionths.  During this period AR 1148 was seen on the 18th and 19th at 27°S/65° of type Bxo and then Axx.

On the 30th and 31st a small Dso group, AR 1150, with an area of 120 millionths was seen at 19°S/182°.

Hydrogen Alpha:

Only 2 Hα observations were made during the month. On the 9th none of the prominences were particularly large but there were several filaments seen including a string of 6 in the SW quadrant. A small region of plage was seen around AR 1145. On the 16th a complex prominence was seen on the NW limb which stretched to a height of about 80000km. Also a pair of nearby spike prominences was seen on the SW limb.  Several filaments were seen mainly in the NE quadrant.

February 2011

The first observation of the month, on the 3rd, showed two small sunspot groups – AR 1150 of type Bxo at 22°S/180° and AR 1152 of type Axx at 19°S/156°.  Both of these groups had decayed on the disk by the time of the next observation on the 8th when 3 other small groups were seen.  These were AR 1153 of type Cao near the western limb at 14°N/173° and two Axx groups at 7°N/151° (AR 1154) and at 20°S/63° (AR 1156).  Yet another set of 4 new small groups were seen on the disk on the 12th: an Axx type at 16°N/111°, Cso type at 20°N/63° (AR 1157), Axx type at 19°N/34° (AR 1159) and Dsi at 20°S/34° and of size 60 millionths (AR 1158). 

AR 1158 then developed rapidly such that when seen on the 14th it was of size 430 millionths and of type Ekc – it was also near the central meridian and was seen with the protected naked eye. On the same day a Bxo group appeared near the eastern limb at 10°N/330° (AR 1161).  When AR 1158 was seen on the 16th it was of a similar size and form (i.e. 3 complex penumbral sunspots and a few other sunspots). AR 1161 had developed into a Dao group with an area of 210 millionths.

No further observations were possible until the 25th when only an Axx sunspot group was seen near the eastern limb at 15°N/183° (AR 1163).  This was joined on the 27th by a Dao group further to the east at 28°N/163° (AR 1164) and an Axx group at 21°S/184° (AR 1165).

Hydrogen Alpha:

Only 2 Hα observations were made during the month. On the 12th there were a number of prominences seen but none were particularly large – however one on the NE limb was quite bright. On the disk there were two small filaments but a flare was in progress at the start of the observing session at 15h10m UT.  The flare was located near AR 1159 and it comprised of two or three parts and it was still visible when clouds obscured with Sun at 15h 30m UT.  Plage was also seen around AR 1158. The other observation on the 27th only showed two small prominences and two filaments, one of which was near AR 1164 together with a small region of plage.

March 2011

On the 2nd AR 1164 at 25°N/163° was nearing the central meridian – it was of type Ekc with an area of 490 millionths and it consisted of a main penumbral sunspot with two adjacent penumbral sunspots.  By the 4th many more penumbral sunspots were seen within the middle portion of the group although its total area was almost the same.  Its appearance changed again on the 7th and 8th when it was nearing the western limb – on the 8th, for example, it consisted of a quite irregular main penumbral sunspot containing several umbra with two smaller penumbral sunspots to the north.  The only other group seen on the 2nd was AR 1165 of type Bxo at 22°S/181°.  By the 4th it was of type Axx before rapidly developing into an Eac type on the 7th when it was close to the western limb.  Only one of the following penumbral sunspots was seen on the 8th. Three other groups were seen on the 4th (giving 5 in total): AR 1168 of type Axx at N24/216, AR 1167 of type Bxo at 14°N/126° and AR 1166 of type Dai at 10°N/91°. AR 1166 was near the eastern limb – as it progressed towards the central meridian it developed into type Ekc with, on the 11th, a total of 660 millionths. As with AR 1164 it changed appearance from day to day with many medium and small sized penumbral sunspots and other sunspots being seen each day. It was last seen on the 14th near the western limb.

On the 7th and 8th an Axx sunspot at 18°N/100° was seen (no AR number). During the period AR 1169 was seen at 20°N/61° – initially it was of type Dao before losing its following penumbral sunspots to become on the 11th and 12th type Cai and then becoming type Hkx on the 14th when its area was at a maximum of 340 millionths.  On the 8th only AR 1170 was seen at 30°S/159° of type Axx and on the 12th and 14th only AR 1172 was seen at 11°N/345° of type Bxo.

By the 19th the number of group seen reduced to just one – AR 1175 which developed on the disk at 13°N/330° and type Cai. Over subsequent days it developed slightly to become type Dao with a total area of 170 millionths before becoming type Cso on the 23rd when it was close to the western limb.

Activity started too increased again from the 23rd with the appearance of AR 1176 near the eastern limb on the 23rd when it was of type Dao.  It was of the same type on the 24th when it was at its largest at 350 millionths. By the 27th and 28th it was of type Eac but smaller at 170 millionths and the number of sunspots within the group were seen to reduce.  During the period from the 24th more small groups were seen, especially in the eastern hemisphere: AR 1179 at 11°N/274° (Axx), AR 1177 at 21°N/204° (Bxo), AR 1178 at 15°S/173° (Dao), AR 1180 at 24°N/163° (Hsx) and AR 1181 at 25°S/158° (Hsx) and AR 1183 at 15°N/135° (Eac).  There were 6 groups seen on the 25th and 28th (the highest number seen on any day this solar cycle so far).

Hydrogen Alpha:

Although prominences were seen on each of the 6 Hα observations, the largest were seen on the 23rd when a combined prominence/filament was seen on the NE limb and a hedgerow prominence was seen on the SW limb. Filaments were more numerous on the 12th and 27th when several were seen in the NE quadrant.  Plage was seen around several groups during the month: on the 7th around AR 1164 and AR 1165; on the 12th around AR 1166, on the 23rd around AR 1176 and on the 24th, 25th and 27th around AR 1176, AR 1178, AR 1181 and AR 1183 (27th only).  On the 12th a flare was seen within AR 1166 between 12h 25m and 12h 45m UT. 

April 2011

One of the four groups seen on the 2nd was AR 1183 near the central meridian at 16°N/134° and of type Eao with an area of 120 millionths. By the following day the leading penumbral sunspot had reduced in size and the number of sunspots within the group reduced. This group continued to decay with none of the following sunspots being seen on the 4th, only a single Hsx sunspot on the 6th and finally just an Axx sunspot close to the western limb on the 7th.  On the 3rd AR 1184 was seen at a similar latitude as AR 1183 having formed on the disk at 16°N/109° and of type Dsc consisting of several small penumbral sunspots and a combined area of 120 millionths. By the following day, the 4th, larger leading and following penumbral sunspots developed. This group grew again by the 6th (to 250 millionths) before beginning to decay as it neared the western limb – it was last seen on the 9th as an Hsx sunspot on the western limb.

Another two nearby northern groups were seen between the 4th and 12th – AR 1185 and AR 1186 at 20°N/32° and 22°N/13° respectively. AR 1185 was at its largest on the 6th when it was of type Dac with an area of 140 millionths. AR 1186 was initially seen as type Hsx near the eastern limb on the 6th before becoming type Dao with an area of 110 millionths on the 9th and then beginning to decaying to type Cai on the 12th. During this period there was a southern group, AR 1187 at 19°S/354° which was initially of type Axx on the 7th, a small Dso group on the 8th (area 110 millionths) before decaying on the disk to type Bxo on the 9th and Axx on the 10th.

On the 11th a Bxo group appeared on the disk at 13°N/338° (AR 1190). By the following day it had become type Cai with many sunspots following the penumbral sunspot. When next seen, on the 16th, the leading sunspot had developed into a complex Hkx sunspot with many umbrae within it and several other sunspots, without penumbra, were still seen following. It had an area of 370 millionths. The number of following sunspots had reduced by the following day (the 17th). A smaller single Hax sunspot was seen when it was close to the western limb on the 19th.

The next significant group was seen between the 16th and 25th (AR 1193) at 17°N/264°. It was of type Eac with an area of 320 millionths on the 16th when it consisted of several penumbral sunspots, especially at the following part of the group. By the 18th, the groups area had increased to 440 millionths before beginning a slow reduction in size as it neared the western limb where it was located on the 24th.  On the 19th an Hsx sunspot was seen close to the eastern limb (AR 1195). As the group rotated away from the limb it appeared as a Dsc type group at 17°S/190°. As it progressed towards the central meridian it developed such that by the 25th it was of type Dao consisting of two penumbral sunspots where the following one was quite irregular in shape and the total area was 350 millionths. When it was last seen on the 30th this group consisted of a single Hsx sunspot close to the western limb.

Hydrogen Alpha:

The most striking prominence seen from 15 Hα observations was on the 9th – this was a thin spike prominence on the SW limb with an estimated height of 100,000 km. It was not visible on the following day. Another interesting prominence was seen on the 17th, also on the SW limb – this consisted of several separate regions many of which were isolated above the limb. Another thin spike-like prominence was seen on the 20th on the NE limb – the prominence was slightly curved with two breaks seen up to the highest point some 150,000 km above the limb.  Filaments were seen on each observing day with up to 7 being seen (on the 8th). However, none were especially long. Plage was seen around several groups during the month: on the 3rd and 8th around AR 1184, on the 8th and 10th around AR 1185, on the 10th around AR 1187, on the 18th and 22nd around AR 1193, on the 20th, 21st, 22nd, 24th, and 25th around AR 1195, on the 20th, 21st, 22nd, 24th, 25th, 27th and 30th around AR 1196 and on the 30th around AR 1199.

May 2011

The largest of the five groups seen on the 1st was AR 1203 at 18°N/55° of type Cao with an area of 150 millionths. By the 2nd a following penumbral sunspot had formed to make the group of type Fao while by the 6th another penumbral sunspot had developed in the middle of the group (this was now the only group on the disk). The area of AR 1203 peaked on the 7th at 260 millionths before it started to decay as it approached the western limb as an Eao type on the 10th.

On the 8th a small Dso group was seen near the eastern limb – AR 1208 at 11°N/320°. By the 10th it has attained an area of 100 millionths as a Dsi group. Although it started to decay, it became type Eso on the 13th before being of type Cso on the 14th. On the 19th a single Hax penumbral sunspot was seen at 15°S/193° (AR 1216). It was slightly larger on the 20th at 90 millionths before reducing in size slightly as it progressed almost unchanged across the disk – it was last seen on the 27th near the western limb.

 AR 1216 was the only group seen on the 24th and 25th. However the observation on the 27th showed five groups, the largest of these being AR1224 at 21°N/130° having just passed the central meridian. It developed into a Dao group of 140 millionths on the 29th before decaying into an Hsx sunspot on the 31st. Of the other groups from 27th, AR 1226 had rotated further from the limb by the 29th to show itself as a Dac group consisting of several penumbral sunspots. On the 30th it was now of type Eac with an area of 320 millionths. However by the following day some of the following penumbral sunspots had begun to decay.  On the 29th another group was seen following AR1226 – AR 1227 at 19°S/22° which was initially of type Cso before becoming type Dao on the 31st with an area of 220 millionths. During this period several smaller groups were seen in the northern hemisphere such that on the 30th a total of seven groups were seen.

Hydrogen Alpha:

On the 12th an impressive arch type prominence was seen on the SW limb with an estimated height of 120,000 km. On the 19th and 20th an extended hedgerow prominence was seen on the SE limb.  Many filaments were seen on each of the 14 Hα observations. A long curved filament was seen on the 1st in the NW quadrant while on the following day the same filament appeared significantly less curved. Another interesting filament was seen on the 20th close to the SE limb as it could be seen to extend across the limb in the form of a low prominence.

Plage was seen around several groups during the month: on the 1st to 3rd around AR 1203, on the 2nd and 3rd around AR 1200, on the 9th around AR 1210, on the 12th around AR 1208, on the 19th and 20th around AR 1214, on the 22nd around AR 1221, on the 29th and 31st around AR 1226, AR 1227 and AR 1128 and on the 31st around AR 1224.

 On the 29th a group of flares were seen within AR 1126 from 1020 to 1050 UT – initially 4 separate bright Hα regions were seen while towards the end of the observing session, several of these bright regions had merged to form a more elongated bright region was seen towards the leading part of the group where a short curved filament was also seen.

June 2011

Overall activity was moderately high during the first week of the month but then dropped quite significantly for the rest of the month. On the 1st six groups were seen, four in the northern hemisphere and two in the south and all were in the eastern hemisphere. The largest of the northern groups was AR 1228 at 18°N/16° which was of type Cai on the 1st and 2nd before becoming type Dai on the 3rd through the appearance of a following penumbral sunspot giving the group a total area of 150 millionths. As this group passed the central meridian it started to decay and it was last seen on the 7th as a Cao group. The two southern groups from the 1st were AR 1226 and AR 1227 at 20°S/37° and 19°S/23°, i.e. both were at a similar latitude and reasonability close in longitude. AR 1226 was of type Dai on the 1st before becoming type Dac on the 2nd with an area of 180 millionths. It then reduced in size slightly on the 2nd, 3rd and 4th before being last seen as a type Axx sunspot on the 7th.  AR 1227 was of type Dso on the 1st with an area of 110 millionths – this group slowly decayed as it progressed across the disk and was last seen on the 10th as a single Axx sunspot.

By the 13th only one group was seen – AR 1234 at 15°S/246° of type Bxo. On the 14th a Hax sunspot was seen close to the eastern limb.  This was AR 1236 at 17°N/168° which became a type Eac group on the 18th with an area of 260 millionths – the leading sunspot being much larger than any of the following sunspots.  Some of the following sunspots had disappeared by the 19th which continued as only a single Hax sunspot was seen on the 23rd and then an Hsx sunspot close to the western limb on the 25th.

No sunspots were seen on the 27th while by the 29th two small group were seen, AR 1242 at 18°N/56° and AR 1243 at 15°N/351°. AR 1242 was of type Dso on the 30th with an area of 120 millionths.

Hydrogen Alpha:

On the 4th two impressive prominences were seen – one of the SW limb shaped like a flame and the other on the SE limb which was quite complex with several regions of hydrogen above the limb extending towards the equator.  Both prominences had an estimated height of just over 100,000 km. On the 11th a spike prominence was just to the north of the equator on the NE limb. A nice arch prominence was seen on the SW limb on the 19th.  An extensive hedgerow prominence was seen along 10° of the NW limb on the 30th.

Filaments were seen on each of the 8 observing days. Three quite long filaments were seen on the 2nd with other long filaments being seen on the 4th and 30th. On the 14th a small filament was seen extending over the NE limb to form a prominence. Also on the 30th a group of small filaments were seen nearing the limb occupied by the hedgerow prominence.

Plage was seen around AR 1226 on the 2nd, around AR 1228 on the 4th, around AR 1236 on the 19th, around AR 1241 on the 25th and 26th. 

Two flares were seen on the 19th from 1610 to 1640 UT (AR 1237) – the shape of the flares changed little but their intensity did reduce towards the end of the observing period.

July 2011

There was quite a contrast in the size of groups between the first three weeks and the last week of the month due to the appearance of three medium sized groups in the northern hemisphere at the month’s end.  On the 1st three groups were seen – these largest being AR 1243 at 17°N/351° of type Dsc with an area of 120 millionths. As it passed the central meridian on the 3rd it become type Cai before changing to type Cao when last seen on the 6th. Two new groups were seen on the 9th (AR 1247 and 1245) but again these were small. Further small groups developed on the disk and rotated onto the disk such that by the 15th six groups were seen including two in the southern hemisphere. The next few observations showed a reduction in the number of groups such that by the 24th there were three groups, one of type Bxo (AR 1259) and two of type Axx (AR 1254 and no AR number).

The next observation on the 28th showed three group of moderate size – AR 1260 of type Eac at 20°N/358° and area 250 millionths, AR 1261 of type Dai at 17°N/329° and area 180 millionths and AR 1263 of type Dao at 18°N/303° close to the eastern limb. AR 1260 comprised of a string of penumbral sunspots although the leader was the largest.  By the 30th the leader had increased in size while the number of penumbral sunspots reduced to make the group type Ekc with an increased area of 350 millionths. It was also near the central meridian. By the following day the leader had reduced in size slightly to make the group type Eac. For AR 1261 more penumbral sunspots had developed by the 30th which had increased in size by the 31st so that the group was now of type Ekc with an area of 320 millionths. Finally AR 1263 had the appearance of a typical bipolar group with most of the group’s area being in the leader and follower sunspots – on the 31st it had increased in size to 490 millionths when it was if type Dac.  

Hydrogen Alpha:

From the 1st to 3rd a hedgerow prominence was seen on the NW limb – on the 3rd other small prominences were also seen towards the north. On the 22nd a group of three prominences were seen down the SW limb all being of different forms. One of these was probably seen again on the 24th as a curved spike type. Also on the SW limb on the 30th a detached spike prominence was seen as well an arch type further towards the south at an approximate height of 80,000 km.

A group of quite long filaments were seen at the start of the month – these were in the NW quadrant on the 1st and they were all seen progressed towards the limb on the 2nd and 3rd. Several small filaments were seen within the three groups from towards the end of the month (AR’s 1260, 1261 and 1263). Plage was also seen around these three groups on the 28th, 30th and 31st, and especially around the middle group, AR 1261.  Earlier in the month, plage was seen around AR 1243 on the 1st, 2nd and 6th and around AR 1254 on the 22nd and 24th.

August 2011

The three medium sized groups from the end of July, ARs 1260, 1261 and 1263, were seen on the 1st spread across the disk with AR 1261 near the central meridian. AR 1260 at 20°N/357° was of type Esc with an area of 360 millionths. By the following day its following penumbral sunspots had disappeared while on the 3rd only a single Hax sunspot was seen near the western limb. AR 1261 was the most complex of the three groups on the 1st – it was of type Ekc at 16°N/330° with an area of 400 millionths.  By the 2nd it had lost some of its surrounding sunspots so that by the 3rd it was of type Dac with an area of 270 millionths. Finally AR 1263, at 18°N/300°, was of type Dko on the 1st with an area of 580 millionths when it comprised two almost equally sized penumbral sunspots. It was still of type Dko on the 3rd although its area had reduced slightly to 460 millionths.  When next seen on the 7th the group had split into a string of penumbral sunspots of type Eac with a total area of 400 millionths. As this group moved towards the western limb the number of sunspots within the group reduced - on the 10th only the following sunspot was seen. AR 1261 and 1263 were seen with the protected naked eye on the 1st and 2nd while only AR 1263 was seen with the protected naked eye on the 3rd.

 The day after AR 1263 had rotated off the disk, the 11th, only three small Axx groups were seen. The largest of the three groups seen on the next observation on the 20th was AR 1271 at 16°N/60° which was of type Dac – unusually the leading part included two penumbral sunspots. By the 22nd, with the group nearing the central meridian, it comprised several irregular penumbral and other sunspots where the total area 170 millionths. This group was last seen on the 27th as a single Hsx sunspot on the western limb. On the last observation of the month, on the 29th, only three Hsx groups were seen.

Hydrogen Alpha:

Observations on the 27th and 28th showed a fine mound type prominence on the SW limb with an estimated height of 90,000 km – on the 28th the upper portion of the prominence was spiked. An extended filament running almost from north to south was seen close to the western limb on both dates.  Plage was seen around AR 1280 on the 27th and around AR 1281 close to the eastern limb on the 28th.

Also on the disk on the 11th was AR 1289 which was close to the central meridian and it was also seen with the protected naked eye. It was a single large irregularly shaped penumbral sunspot and a few following small sunspots – it was of type Hkx and at 24°N/127° with an area of 400 millionths. By the 13th it has lost the following sunspots but then it started to decay as it progressed towards the western limb – by the 16th it had an area of 360 millionths and it was last seen as a single type Hax sunspot close to the limb.

By the observation on the 23rd the number of groups seen had reduced significantly from the middle of the month to three, one of these was AR 1302 of type Fkc at 14°N/280° and close to the eastern limb. By the following day more of the group could be seen to show a large leading penumbral sunspot and several smaller penumbral following sunspots and where the total area was 1100 millionths. On the 25th the group had a similar total area but the leading sunspot was more irregular and the number of following penumbral sunspots had reduced to two. When next seen on the 28th the group was near the central meridian and it consisted of two irregular penumbral sunspots – the leader being more than twice the size of the following. The total area had reduced to 800 millionths. This group continued to reduced in size such that on the 30th it was just 430 millionths after the leading sunspot had split into two. AR 1302 was seen with the protected naked eye on the 24th, 25th and 28th to 30th.

Hydrogen Alpha:

From 9 observations, the highest number of prominences was seen on the 1st, six, including a pyramid prominence on the NW limb and a hedgerow prominence on the SE limb. On the 4th a small but bright prominence was seen on the NW limb. Meanwhile on the 11th a detected oval shaped prominence was seen above the equator on the E limb. The only other notable prominences were seen on the 13th as a pair of nearby flag shaped prominences on the NE limb.  Many of the filaments seen were small in length but some were longer such as two in the NE quadrant on the 1st, three in the N on the 3rd and 4th, one in the NE on the 13th and one in the S on the 30th. Several flares were seen – on the 11th at 09h 15m UT near AR 1283 and close to the NW limb; on the 14th at 16h 40m 2 separate flare regions, one near AR 1297 in the SW and the other near AR 1296 in the NE with the latter comprising several flares and on the 25th at 09h 30m to 09h 55m UT near AR 1302 (type M1.5).  In addition to the flare near AR 1296 on the 14th, an extensive region of plage was around this group on the 13th and 14th.

The first observation of the month on the 4th showed four groups, the largest being AR 1339 at 20°N/104° and near the eastern limb. It was a complex group of type Fkc with an irregularly shaped main sunspot with several smaller penumbral sunspots to the north and east – it had a total area of 1600 millionths. By the next observation on the 13th this group was near the western limb but it had decayed to be a small Dac type. It was not seen on the 15th.

On the 13th, 15th and 17th, nine groups were seen on each day – these were all fairly small and the majority were in the northern hemisphere. The number of groups had reduced to seven by the 19th but by the 25th the number of groups has increased again to ten – now there was a string of groups in the northern hemisphere being evenly spread from the eastern to western limb. Although the number of groups had reduced to seven on the 27th, there was still a spread in the northern hemisphere while just one Axx sunspot was seen in the southern hemisphere. By the 30th the disk was of a similar appearance with small groups seen – the largest being AR 1362 at 7°N/131° of type Dai and total area of 150 millionths.

Hydrogen Alpha:

The first observation of the month on the 9th showed seven groups with five in the north and two in the south – the largest was AR 1363 at 21°S/108° of type Hax with an area of 260 millionths. Being close to the western limb it was only seen again on the 10th. By the 13th the number of groups had reduced to three with AR 1374 being the largest – this was nearing the central meridian at 18°S/352° of type Hkx with an area of 210 millionths. On subsequent observations, it reduced in size becoming type Hax on the 15th and it was last seen on the 17th with a size of 80 millionths. During the period up to the 17th, the number of group increased to seven but all were small (AR 1374 was still the largest).

The observation of the 22nd showed some slightly larger groups. AR 1376 close to the western limb at 19°N/308° was of type Dko having been previously seen as type Axx on the 17th. AR 1382 at 17°S/260° had an area of 240 millionths was of type Eac which consisted of a collection of small penumbral and other sunspots throughout the group (the largest sunspots were in the middle of the group). The largest group seen during the month was AR 1384 with an area of 450 millionths being a bipolar Dko group at 15°N/199°.  The other two group seen on the 22nd were both small.

Hydrogen Alpha:

The Hα observation on the 3rd showed a number of prominences with the largest being a bush type on the NW limb.  Many medium sized filaments were also seen – these were mainly in the northern hemisphere. Plage was seen around AR 1363.

Page created on 02 January 2011.