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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.
The first sunspot group of the new solar cycle, AR 981, was seen on the 5th as two sunspots in a group of type Axx at 28°N/249°. These were not seen on the following day. The only other group seen from the eight observations made during the month was on the 30th - AR 982 at 9°S/247° was from the old cycle as was seen as a collection of 5 sunspots of type Bxo. The six observations made between the 6th and 27th all showed a blank disk. Hydrogen
Alpha: Prominences seen on the 5th, 6th and 13th were not particularly striking. On the 27th an arch type prominence was seen on the SE limb while further towards the equator a bright but not particularly tall prominence was seen. By the 30th quite long filaments were seen on the eastern part of the disk together with plage around AR 982. In fact these filaments appeared to be pointing towards this active area. Also on the 30th another small but bright prominence was seen near the equator on the eastern limb.
On the 2nd AR 982 was observed under poor seeing conditions an Axx group consisting of two small sunspots. On the 9th a short-lived Bxo group was seen at 3°N/118° (it was not seen on the preceding or following days and was not reported by NOAA). The other 5 observations made during the month showed blank disks. Hydrogen
Alpha: 5 Hα observations were made during the month. The most striking prominences seen were on the 10th on the W limb and on the 16th & 17th on the NE limb. Both were of the hedgerow type. No filaments were seen.
No sunspots were seen until the observation of the 24th when the Dsc group of AR 987 at 7°S/261° and the Cso group of AR 988 at 7°S/236° were both seen in eastern hemisphere. By the 29th AR 987 had reduced in size slightly from 90 to 50 millionths while AR 988 had developed into an Eao group with an area of 140 millionths. These two groups were joined by a third group, AR 989, at 11°S/207°. On the 31st AR 987 had reduced to a single Hsx spot approaching the western limb, AR 988 had lost its following penumbral spot although its area had increased to 190 millionths and AR 989 was no longer visible having decayed on the disk. Hydrogen
Alpha: From the 7 Hα observations made during the month the most striking prominences seen were on the 21st when four were visible, three on the eastern limb and one on the western. One of these consisted of arches. Filaments were much more visible than during recent months, especially at the start and end of the month. On the 2nd, for example, four regions of filaments were seen while on the 24th and 29th a long filament was seen to the south of AR 988. A flare was seen during a short observing session from 14h 40m to 14h 50m on the 24th within AR 988. Plage was seen around all three active regions of AR 987, AR 988 and AR 989 on the 29th.
AR 987 and AR 988 were still visible on the 1st although AR 987 was an Axx spot close to the western limb and it had rotated around the limb by the time of the next observation on the 3rd. AR 988 was a single Hax spot on the 1st and 3rd and it had disappeared by the 4th. No further sunspots were seen until the observation of the 22nd when AR 992 had developed on the disk as a Bxo group at 14°N/274°. This group was seen again on the following day but not on the next observation on the 26th. Hydrogen
Alpha: Prominence activity was quite low during the month with at most four prominences seen on any of the 15 observations – none of the prominences seen were particularly striking. Filaments were seen on the 3rd and 4th and again on the 23rd and 26th. Plage was seen around new cycle AR 990 on the 14th, 15th, 16th and 17th.
On two small sunspot groups were seen during the month. AR 994 was seen at 12°S/311° on the 18th as a Bxo group and 19th as an Axx spot. The other group was AR 996 also on the 19th at 7°N/258° as a Bxo group. The other 18 observations made during the month, from the 1st to 14th, 22nd to 24th and the 31st all showed blank disks. Hydrogen
Alpha: A dynamic prominence was seen on the 14th on the SE limb. At 07h15m it was seen as a tower of hydrogen that turned through a right angle and then fell back towards the limb. When observing later the same day at 16h45m, this prominence had changed shape to appear more like a wind sock and it was changing shape over the timescale of a few minutes with regions of hydrogen appearing and disappearing. Another active prominence was seen on the 14th also on the SE limb but not as bright on the above dynamic prominence. Plage
was seen around AR
994 on the 18th
and 19th and around AR
996 on the
18th, 19th and 22nd.
Only two small sunspot groups were seen during the month. AR 998 was seen on the 10th at 11°S/291° as an Axx group and AR 999 was seen on the 22nd just south of the solar equator at 1°S/202° as a Bxo group. The other 16 observations made during the month, from the 4th and 5th, 8th and 9th, 13th to 15th and 23rd to 30th all showed blank disks. Hydrogen
Alpha:
Only one small sunspot group was seen during the month. AR 1000 was seen on the 19th at 12°S/179° as a single Axx sunspot. The other 24 observations made during the month, from the 1st to 8th, 10th, 12th to 16th, 19th, and 21st to 30th all showed blank disks. Hydrogen
Alpha: The number of prominences seen on each of the 25 observations varied between 1 and 4. Quite a bright prominence was seen on the 13th and 14th on the SE limb. A much taller but fainter prominence was seen on the NW limb on the 25th (it was also seen on the 23rd and 24th and again on the 26th but much shorter on each occasion). Small filaments were seen on the 15th and 21st. Plage was seen around AR 1000 on the 21st.
No sunspots were seen from 19 observations. Hydrogen
Alpha: Although no sunspots were seen, prominences were visible on each of the 15 days that Hα observations were made. A tall prominence was visible on the 1st on the NW limb – in fact the Moon passed in front of it during the solar eclipse. Other tall prominences were seen on the 22nd (NW limb) and the 31st (SE limb). Filaments were seen on the 15th, 23rd to 25th and on the 30th when the longest filament was seen. A small region of plage was visible in the NE quadrant of the Sun on the 23rd and 24th (at approximately 15°N/65°).
On the 29th a single sunspot was seen under excellent seeing conditions at 01°S/353°. The other 15 observations made during the month, including the 28th, showed spotless disks. Hydrogen
Alpha: The most striking prominence seen during the month was on the 28th on the SE limb. It comprised of two parts, a brighter part near to the limb and a faint part that stretched some 100,000 km above the limb. During the day both parts changed appearance with the faint tall part still being visible. Filaments were seen on the 20th and 21st. One of the four filaments seen on the 21st extended across the limb as a prominence.
Three new cycle groups were seen: AR 1005 on the 12th at 28°N/119° of type Cso, AR 1006 on the 16th at 24°S/154° of type Axx and AR 1007 on the 31st at 36°N/251° of type Bxo. The other 14 observations made during the month showed spotless disks. Hydrogen
Alpha: On the 12th, the umbra of the leading sunspot of AR 1005 was seen in Hα along with some following plage. Plage was also seen in the NW quadrant of the solar disk on the 17th. The Hα observation on the 18th showed nine prominences including a bright compact prominence on the SW and a high detached prominence on the NE limb which was estimated to be at least 100,000 km above the limb. A prominence was seen in the same location but much closer to the limb on the previous day. No filaments were seen from seven observations made during the month.
One new cycle group was seen during the month: AR 1008 from the 11th to 15th inclusive. On the 11th AR 1008 was at 33°N/121°, of type Dso with an area of 60 millionths. By the following day, the following penumbral spots had reduced in size to leave a Cao type group. All the following spot had disappeared by the 14th making an Hsx group while on the 15th just single Axx spot remained. The other seven observations made during the month showed spotless disks. Hydrogen
Alpha: Only three Hα observations were made during the month. The observation on the 15th showed three small prominences with a small filament close to one of these. Plage was also seen at the location of AR 1008. On the 22nd five prominences were seen including a string of prominences down to NE limb together with a filament near the northern end of these prominences. There were fewer prominences on the following day, four, with those on the NE limb were still visible although they had changed shape.
Only one group was seen during the month: AR 1009 on the 10th at 24°S/145° and of type Bxo. No further observations were possible until the 17th when this group would have rotated off the disk. The other 13 observations made during the month showed spotless disks. Hydrogen
Alpha: On the 6th a series of prominences were seen on the NE limb which were seen extending onto the limb in the form a filament. The prominences were still present on the 7th while the filament has moved away from the limb and was seen in two parts. On the 10th a small region of plage was seen around AR 1009 - an incomplete arch prominence was also seen on the NW limb. Observations on the 19th, 20th and 21st showed only small prominences - three small filaments were also seen on the 21st. A faint but extensive prominence was seen on the NE limb on the 26th while on the 30th just two sets of prominences were seen on the W limb.
Page created on 28 December 2007. |
