{"id":3395,"date":"2022-02-02T17:42:51","date_gmt":"2022-02-02T17:42:51","guid":{"rendered":"https:\/\/www.popastro.com\/main_spa1\/solar\/?page_id=3395"},"modified":"2022-02-02T17:49:23","modified_gmt":"2022-02-02T17:49:23","slug":"solar-highlights-for-december-21","status":"publish","type":"page","link":"https:\/\/www.popastro.com\/solar\/solar-highlights-for-december-21\/","title":{"rendered":"Solar Highlights for December 21"},"content":{"rendered":"

Solar Rotation Nos: 2251 to 2252<\/p>\n

Solar Cycle No.25 seems to be showing more sunspot activity than previously expected in earlier forecasts. This seems likely if recent sunspot activity is anything to go by.<\/p>\n

Persistently cloudy weather severely impacted solar observations in December. The southern hemisphere was more active than the north this month particularly from mid-December onwards.<\/p>\n

Here are the highlights of solar activity for December 2021 together with a selection of images.<\/p>\n

Sunspots<\/strong><\/p>\n

AR2898<\/strong> appeared on the disc in late November at -24\u00b0. It was seen nearing the west limb on December 1st. It went over the limb on the 5th.<\/p>\n

AR2900<\/strong> appeared preceding AR2898 in late November at -28\u00b0 and was still visible on December 1st nearing the west limb passing over it by the 5th.<\/p>\n

AR2904<\/strong> appeared on the 6th at -27\u00b0 What was notable about it was that on the 7th and 8th it was the only sunspot visible, near the CM.<\/p>\n

The Sun appeared blank of sunspots from the 9th to the 13th.<\/p>\n

AR2905<\/strong> came into view between the east limb and the CM on the 13th at -11\u00b0, type Cro consisting of 2 sunspots. It remained fairly quiet as it crossed the solar disc and was not seen after the 17th.<\/p>\n

AR2906<\/strong> appeared much farther south at -29\u00b0 on the 14th, initially type Bxo. It developed rapidly over the following few days reaching a peak around the 17th and was C-class flare active at one point. It seemed to fade after the 19th.<\/p>\n

AR2907<\/strong> also developed into view on the 14th at -21\u00b0, initially type Bxo, it developed rapidly by the 15th to type Dki and was C-class solar flare active. This Active Region plus AR2908 and AR2909 formed a trail of sunspots along the southern hemisphere from the 16th onwards.<\/p>\n

AR2908<\/strong> appeared around the 16th at -21\u00b0, type Dko. It reached a peak around the 18th to 20th and produced an M-class flare on the 20th plus a few C-class flares over the Christmas period.<\/p>\n

\"2021
2021 December 15 1124-1152UT White Light and Calcium H. Images by Carl Bowron.<\/figcaption><\/figure>\n

At this time the Sun appeared very spotted but many UK observers were prevented seeing it due to overcast skies.<\/p>\n

\"2021
2021 December 17 1410UT White Light whole disc. Image by Cliff Meredith.<\/figcaption><\/figure>\n

AR2909<\/strong> came into view around the 16th at -21\u00b0, type Dao. It remained fairly static up until the 22nd when it seemed to fade.<\/p>\n

AR2916<\/strong> appeared on the 22nd at -16\u00b0 and developed rapidly to type Ekc by the 26th. It was less flare active by the 28th by which time it was at the CM. At the end of the year AR2916 was seen to be decaying as it neared the west limb.<\/p>\n

AR2917<\/strong> appeared on the 23rd at -27\u00b0 initially type Bxo but then developing to type Cro after the 24th until it suddenly disappeared after the 26th.<\/p>\n

AR2918<\/strong> also appeared on the 23rd at +20\u00b0 type Cro, one of few northern hemisphere sunspot groups to appear this month. It seemed to peak around the 26th to 29th remaining visible until the end of the month.<\/p>\n

SPA Sunspot Mean Daily Frequency: 2.04 (was 2.17)<\/strong>
\nRelative Sunspot Number: 30.20 (was 26.26)<\/strong><\/p>\n

Solar Prominences, Plage, Filaments and Flares<\/strong><\/p>\n

Very limited coverage this month due to low Sun and poor weather.<\/p>\n

There were a few small prominences seen in early to mid-December plus some isolated filaments and areas of bright plage.<\/p>\n

\"2021
2021 December 18 1040UT Ha whole disc drawing by Ian Lee.<\/figcaption><\/figure>\n

The arrival of AR2907, AR2908 and AR2909 also brought several bright areas of plage and some small filaments on the 18th. The 19th saw some particularly impressive areas of plage and filaments.<\/p>\n

\"2021
2021 December 19 1240UT Ha whole disc drawing by Ian Lee.<\/figcaption><\/figure>\n

SPA Prominence Mean Daily Frequency: 2.83 (was 4.14)<\/strong><\/p>\n

Congratulations to Alan Heath who observed 16 days, to Michael Fullerton on 12 days and to Jonathan Shanklin who achieved 11 days.<\/p>\n

Detailed count records of Active Regions and Relative Sunspot Numbers came from: Simon Brown, Michael Fullerton, Alan Heath, Ian Lee, Jonathan Shanklin, Brendan Shaw and Bob Steele.<\/p>\n

Images and drawings were supplied by: Carl Bowron, Ian Lee and Cliff Meredith.<\/p>\n

Geoff Elston<\/p>\n","protected":false},"excerpt":{"rendered":"

Solar Rotation Nos: 2251 to 2252 Solar Cycle No.25 seems to be showing more sunspot activity than previously expected in earlier forecasts. This seems likely if recent sunspot activity is anything to go by. Persistently cloudy weather severely impacted solarRead more<\/span><\/a><\/p>\n","protected":false},"author":17,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[],"tags":[],"class_list":["post-3395","page","type-page","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t