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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.
One group dominated activity during the month. This was first seen as a Dac group at 14°N/179° on the 12th with an area of 380 millionths and situated half way between the eastern limb and the central meridian. It comprised three close irregular penumbral spots and a couple of other small nearby spots. By the following day, the 13th, the group had grown almost by a factor of three to 940 millionths and it was now a single irregular penumbral spot with many umbrae within it. This single penumbral spot grew further by the 14th to 1290 millionths and then to 1790 millionths on the 15th when it was of type Ekc and close to the central meridian. On both of these dates, the shape of the main spot changed as did the number and position of the many umbrae. By the 16th the spot grew slightly to 1880 millionths and its shape had also changed slightly from the previous day. When next seen on the 18th, the main spot had decayed such that there were now several small penumbral spots in the leading and following group locations; the largest penumbral spot was towards the following portion of the group. Its area was estimated to be 1340 millionths. The final observation of this group was on the 21st when it was close to the western limb as a slender penumbral spot with a smaller penumbral spot to its north.
The large Ekc group from January was seen on its next rotation as a small Hsx spot close to the eastern limb on the 7th. An extensive area of faculae was seen around this spot, at 16°N/180°, and a nearby Csi group at 9°N/186°. A total of six groups were seen on the 12th. Three were roughly at the same latitude and all were in the eastern hemisphere. The group nearest the central meridian was of type Hax at 9°S/154° which has an area of 240 millionths. On the 15th it was of type Dao but smaller at 150 millionths. On the 18th and 19th it was a small Hsx spot. The middle of the three groups was a Hsx spot at 5°S/137° on each of the 4 observations. The eastward most group was the largest seen during the month. On the 12th it was seen as a Dko group at 8°S/120° with an area of 330 millionths. On the 15th the main spot had grown and had a few surrounding spots, some being penumbral, to give a total area of 460 millionths. The number of surrounding spots had reduced by the 18th although the total area increased slightly to 470 millionths. The group then began to decay such that when it was last seen nearing the western limb on the 21st, it was of type Hax. Observations on the 26th and 27th showed a different single Axx spot while on the 28th the disk was devoid of sunspots.
No spots were seen on the 3rd while on the 5th and 6th just a single Hax spot was seen in the northern hemisphere at 12°N/196° with an area of 90 millionths on the 6th. By the 10th this group had adjacent spots to make it type Csi. When seen on the 12th and 13th, it had become a Hsx group. On the 10th a Dac group was seen at 5°S/157° with an area of 140 millionths which comprised a string of small penumbral and other spots. By the 13th, the total area increased slightly to 170 millionths through there being more penumbral spots. On the 16th a more dominant leading penumbral spot had developed; this spot was the only one present on the 17th and 18th when it was nearing the western limb. Another southern group was seen some 30° to the east. It was first seen as an Hsx spot on the 10th at 8°S/123° and then as a single Hkx spot with two umbrae until the 16th when a close by spot appeared. Further nearby spots appeared on the 17th and by the 18th there was a small leading penumbral spot. On the 19th this group reached it maximum area of 350 millionths as a Dkc group and it was nearing the western limb. On the 23rd two small groups were seen at 12°S/52° of type Dso and at 11°N/344° of type Dsc. The former group must have decayed in the disk by the 25th while the latter decayed to become an Hsx group on the 28th. In addition to the spotless disk on the 3rd, no spots were seen in the northern hemisphere between the 16th and 19th and no southern spots were seen on 5th, 6th and 28th.
Activity during the first three weeks of the months was quite low with just 7 groups seen during this period; only 2 of these were in the northern hemisphere. Probably the most prominent of these was an Hsx spot seen close to the eastern limb on the 5th at 6°S/126°. On the 7th the penumbral spot was asymmetrical and its area was estimated to be 110 millionths. By the 11th several small spots were seen surrounding the penumbral spot which now had an area of 60 millionths. It was also near the central meridian and the only group on the solar disk. By the 16th, only a small Hsx spot was all that remained of this group and it had disappeared by the 17th. The solar disk was spotless on the 24th. By the 26th an Hkx spot had rotated onto the disk at 7°S/230°. On the 27th this spot had an area of 530 millionths; the main umbra was towards the leading part of the spot while several small umbrae were seen towards the following part of the penumbral spot which was quite irregular in shape. By the 29th the Hkx spot had grown to 890 millionths and a region of photosphere was seen within the penumbra. Although several umbrae were seen, there was still just one main umbra. On the 30th the group was now of type Dkc and had become more asymmetric with regions of penumbra extending northwards and southwards. The region of photosphere within the penumbra had grown slightly while the area of the group was similar to the previous day. It was also close to the central meridian.
The dominant group of the first week was the Dkc spot at 7°S/230° which was just past the central meridian on the 1st. On this date it had an area of 850 millionths and it still comprised one irregularly shaped penumbral spot with the main umbra to its west and an area of photosphere to its east. Several small spots were seen around the main spot. As this spot neared the western limb, it began to reduce in size and lose its surrounding spots. On the 6th, the group now consisted of a much smaller irregular penumbral spot and two smaller penumbral spots to its south. On the 7th just one penumbral spot was seen on the solar limb. On the 2nd an Hsx spot was seen close to the eastern limb. By the 5th a loose collection of several penumbral and other spots were seen at 7°S/130° with a total area of 180 millionths. Over the next two days, more small spots appeared which had spread out in longitude to make the group of type Fac. On the 8th the group expended some 20° in longitude which included the central meridian. By the 9th the leading penumbral spot had grown slightly; on the 10th there were three leading penumbral spots which gave the group a total area of 240 millionths. When seen on the following day, these penumbral spots had merged to give an elongated irregular penumbral spot of almost 10° in length; the size and number of following spots had reduced. With the group nearing the western limb on the 12th, the penumbral spot had split into three. When last seen on the 13th just a single small irregular spot remained. An Hsx spot was seen on the eastern limb on the 8th at 13°N/52°. As the spot rotated further onto the disk a following spot could be seen to make the group of type Eko on the 10th with an area of 450 millionths. On subsequent days the size of the group reduced such that on the 15th it was of type Dac with an area of 180 millionths. On the 17th, 18th and 20th just an Hsx spot was seen. In fact on the 20th it was the only spot visible on the solar disk. The largest of the groups seen after the 20th was first seen on the 22nd as a Dso group at 8°S/237° comprising 2 small penumbral spots. On the 24th more small spots had appeared within the group although its total area remained similar at 110 millionths. It was only with the group straddling the central meridian on the 27th did the size of the penumbral spots increase to give a total area of 140 millionths. On the 30th and 31st, the group became type E but the penumbral spots were only seen at either ends of the group with a few spots between.
On the 4th an Hsx spot was seen close to the eastern limb at 10°N/55°. By the 7th, the penumbral spot appeared asymmetric with three umbrae within it: two following spots were also seen. On the 9th following penumbral spots appeared and by the 10th the group was near the central meridian, of type Dkc and 320 millionths in size. During the passage to the western limb, the size and number of spots reduced such that on the 14th a single Hax spot was all that remained. This spot was last seen on the 16th. To the south and slightly to the east was another group that was to become the largest seen during the month. It was first seen on the 7th as an Ekc group at 5°S/43° with an area of 370 millionths. It comprised two penumbral spots, the following being quite asymmetric with its largest length being in latitude. By the 9th, the following spot decayed into three small penumbral spots while the leader had doubled in size and it also had its largest dimension in latitude. On the 10th the groups size increased to 560 millionths. As this group neared the western limb it also decayed as by the 12th it was of type Cao with a much smaller leader spot and a collection of follower spots. On the following day, the number of followers reduced and by the 15th an Hsx spot with an area of 280 millionths was all that remained. This spot was last seen on the 17th. On the 14th a single Axx spot was seen at 15°S/335°. By the following day this spot had rapidly grown into a Dac group with a total area of 180 millionths. It had the appearance of a bipolar group with asymmetric leading and following penumbral spots: there were a few other spots between them. On the 18th, the length of the group increased slightly so that it was of type Eac on the 18th and Eao on the 19th when the group had an area of 330 millionths. As the group neared the western limb the number of spots reduced such that on the 22nd just the leader and follower spots were all that remained. Observations from the 17th to 19th, 21st and 22nd the northern hemisphere was spotless while on the 24th, 26th and 27th there were no spots seen in either hemisphere. The final two observations of the month on the 28th and 29th the southern hemisphere was seen as spotless.
There was a marked increase in activity on the 1st compared to the previous observation on the 29th June. Of the seven groups seen four had developed on the disk, two were seen on the previous observation and the other had rotated around the eastern limb. One of the groups that had developed on the disk was seen as a Dao type at 1°S/100° with an area of 190 millionths. It comprised asymmetric leader and follower penumbral spots with a few spot in between. By the 4th this group had grown into type Eac with an area of 570 millionths. At the leader part of the group was the largest penumbral spot with several umbrae within it while at the following position there were two similarly sized penumbral spots. Unusually, this group straddled the solar equator hence it had spots in both hemispheres. The appearance of this group was similar on the following day, the 5th, but on the next observation on the 9th only an Hsx spot was seen close to the western limb. The group seen on the eastern limb on the 1st consisted of a collection of penumbral spots on the 4th when it was of type Dac at 12°N/56° with an area of 370 millionths. By the 5th just two irregularly shaped penumbral spots were seen but on the 9th these had separated again to form a group with many penumbral spots each of roughly the same size, although the total area had reduced to 190 millionths. This group had changed little on the 10th and 11th but by the 12th, the number of penumbral spots had reduced but those remaining had increased in size. As this group neared the western limb on the 13th an elongated irregular penumbral spot was seen together with a small penumbral spot to its south. On the 14th a single slender penumbral spot was seen on the limb. The number of groups seen peaked on the 4th with a total of nine which had reduced to four by the 9th. By the 15th there were just two groups nearing the western limb while on the 16th just one remained. This had rotated around the western limb by the 17th when there was a spotless disk. Observations made on the next four days, the 18th to 21st, also showed a solar disk devoid of spots. On the 24th a Cso group was seen at 14°N/153° with an area of 70 millionths. This group was also seen on the 28th together with an Axx spot at 15°N/111° and a Dsc group close to the eastern limb at 11°N/56° .
On the 21st a complex Dkc penumbral spot at 10°S/226° lay between the central meridian and the western limb. Several umbrae were seen within the single penumbral spot and it had a total area of 630 millionths. On the 23rd, this spot appeared quite foreshortened as it was close to the limb but it was still of type Dkc. It was not on the solar disk on the 25th having passed around the limb. Also on the 21st a string of small spots was seen at 17°N/159° (type Bxo). By the 23rd a penumbral spot had formed at the following portion. When next seen on the 25th another penumbral spot had developed, this time at the leading part of the group and all the small spots had disappeared between the leader and follower part of the group (there were still some around the follower spot). On the 25th a collection of small penumbral spots appeared close to the eastern limb at 11°N/59°. This group was of type Dac. By the 28th just two small penumbral spots remained together with several other spots at the leading position; the groups total area was 70 millionths. By the 30th this group was classified as type Bxo but by the following day a leading penumbral spot had appeared to make the group type Cao.
One sunspot group dominated activity during the month. This group was first seen on the 8th as an irregular penumbral spot close to the eastern limb at 10°S/231°. When seen on the 9th it still comprised a single irregular penumbral spot containing several umbrae and one other spot at the leading position. It was of type Ekc. Other smaller penumbral spots had developed around the main spot by the 10th; the total area was estimated to be 930 millionths. When next seen two days later, the appearance of the group had changed considerably; now there were many penumbral spots throughout the length of the group with the largest being in the middle. The total area was now 810 millionths. The group had a similar appearance on the 13th although its length had increased slightly to make it type Fkc and it was nearing the central meridian. By the 16th the now Ekc group had its largest spot was at the leading part of the group with a few small penumbral spots following and the total area had reduced to 540 millionths. This group had further reduced in size by the 17th when it was of type Eac and had an area of 320 millionths. It was last seen on the 19th as an Hax spot close to the western limb. This group was seen on the previous rotation, from 15th to 23rd August. The northern hemisphere was seen spotless from the 1st to 4th, 12th and 16th while the southern hemisphere was seen spotless on the 7th, 22nd and 23rd.
Activity significantly reduced during the month with only four small groups observed. These were at 9°S/25° on the 3rd and 4th; at 8°S/287° on the 4th, 8th and 9th; at 13°S/245° on the 10th and 11th; at 8°N/112° on the 15th, 16th, 20th and 21st. The largest group seen during the month was the second of the four groups on the 4th at 70 millionths when it was of type Dso. The northern hemisphere was seen spotless on the 3rd and 4th and between the 8th and 11th, the southern hemisphere was seen spotless on 15th, 16th, 20th and 21st while both hemispheres were seen spotless on the 23rd and between the 25th and 27th.
The most prominent of the 6 groups seen during the month was first seen on the 13th close to the eastern limb as an Eao type group at 6°S/81°. On the following day it could be easily seen that the main spot of the group was the leader; a string of small penumbral spots were seen between this spot and the much smaller follower spot. By the 15th the leader appeared larger but there were fewer penumbral spots throughout the group. The total area was estimated to be 600 millionths and it was now of type Fkc. This group was of a similar appearance and size on each of the following 4 days. The group straddled the central meridian on the 18th. On the 20th, the number of penumbral spots reduced to just two (the leader and follower) and the size of the group reduced to 480 millionths. The last observation of the month, on the 22nd, showed that the several penumbral spots had appeared just to the following side of the leader spot. This group was seen with the protected naked eye every day between the 16th and 20th. All of the other 5 groups seen were small and only one of these was in the northern hemisphere (an Axx spot at 12°N/177° on the 17th only). The solar disk was seen spotless on the 4th, 9th and 12th.
The largest group seen during the month was seen on the 4th at 3°S/255° as type Eai with an area of 320 millionths. This group had just passed the central meridian and consisted of an irregular follower spot and a much more symmetrical leader together with a few spots in between. When seen on the 7th and 8th only a small Hsx penumbral spot was seen close to the western limb. This Hsx spot was seen again later in the month when it re-appeared around the eastern limb on the 24th at 2°S/262°. Its appearance changed little when seen on the 25th to 28th. On the 10th a Dso group was seen close to the eastern limb at 19°N/86°. On the following day several small spots had appeared within the group and that the leader could be seen as being slightly asymmetric in shape. On the 12th the total area of the group was estimated to be 220 millionths. By the next observation on the 17th, the group had become type Hsx with two close by small spots and it had an area of 160 millionths. The size of this group reduced as it neared the western limb with an area of 90 millionths when last seen on the 19th. On the 17th and 18th a Bxo group was seen at 9°S/40° but by the 19th a Dac group had developed on the disk with an area of 170 millionths. This group had decayed by the 24th as just an Hsx spot was seen close to the western limb. A similarly sized Dsc group was seen on the 24th at 17°N/322° with an area of 180 millionths. On the next day it was seen crossing the central meridian but it had started to decay, first as a Cai and Cso type group on the 25th and 26th with an area of 60 millionths and then as an Hsx spot on the 27th and 28th with an area of 30 millionths. Unlike the previous 12 months observations there were spots in both hemispheres on all 15 observations made during the month.
Last updated on 30 January 2006. |
