Solar Section
Director: Richard Bailey
Director: Richard Bailey
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September 2011
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SPA SOLAR SECTION
September 2011
Rotation Nos. 2114, 2115
WHITE LIGHT
A much better month for solar observation . Not only were more AR’s seen regularly, some were of good size . One of them towards the end of the month, NH AR1302 , was large, and 11 AR’s seen on the disk on the 17th was a new high for Solar Cycle 24. Compared to August the MDF for AR’s was more than doubled, as was R ( sunspots ). The NH was much busier than the SH . Flare activity also increased . Lee Macdonald recorded his highest R count of the Cycle so far.
Week 1. Seven AR’s on the 1st, to 4 on the 7th. NH AR’s 1277,79 and 82 were closely clustered near the CM on the 1st. and what was to become a strong AR, NH 1283 as four small spots was near the E rim. AR1281 was lonely nearing the CM in the SH until AR1287 appeared on the 3rd in the E.
Week 2. During the week AR’s increased in number from 4 to 11 on the 17th, AR1283 decayed as it neared the W rim, SH 1287 also. NH AR1289 was the best with a leader having a large split umbra, seen by Lee with his (protected) naked eyes. AR’s in both hemispheres were spread across the disc .
Week 3. AR activity stayed steady in slightly lower figures after the double figure start , 6 AR’s being seen on the 19th. including a NH AR’s 1295,96 and 98
as a cluster. Paul Brierley made a detailed disc drawing on the 18th.
Week 4 to end of month. Between 4 and 8 AR’s were regularly seen. The AR of the month, NH AR1302 appeared in the E on the 23rd. and was to dominate the disk, ever changing to the last day by when it was just past the CM. Showing three splendid and intricate penumbral areas with fine umbra, the leading umbra was Earth sized Big, spectacular wrote Lee. Ian Lee, Alan Heath, Brian Gordon-States and Lee saw it with their ( protected ) eyes on several days. Dale Holt sent in a detailed drawing. From about the 28th.it formed part of a long chain of varying NH AR’s right across the disk , the SH being empty.
Limb faculae was regularly seen by observers including Alan and Brian.
Peter Paice’s continuing fine disc montages showed a good deal of the activity during the month.
MDF 5.31 R 78.61
H APLHA
Although a much increased MDF for AR’s was recorded for this month, the MDF for prominencies remained much as last month.
An increased amount of flare activity was a highlight. With the increased number of AR’s in the month came a very large one in the later days, NH AR1302 . This, plus NH AR1286 in Week 1 and NH group AR’s1295 and 96 , produced some strong flares . NH1302 also showed several lengthy sinewy filaments and bright plaging . Plaging and small filaments were often seen to smaller but strong AR’s.
Prominencies . Large ones with fine detail and varying structures were seen almost daily, as were small ones around the perimeter. Ian Lee observed and drew many of the beautiful prominences . Both Ian and the Director noted that prominence activity became low for a short time about mid-month. Lee reported a faint very large E limb one and a bright flare at 1250ut to NH AR1283 on the 1st.
He observed another flare on the 28th . in NH AR1302 at 1230ut, large with massive changes over 20 minutes. Alan and the Director saw flares on several days to the larger AR’s.
MDF 4.89
Further splendid pictures, drawings and detailed descriptions came from Ian Lee, Paul Brierley, Ian Phelps, Alan Clitherow and Dale Holt .
Observers : Ian Lee Alan Clitherow Michael Fullerton ( a new observer ) Dale Holt Peter Paice Brain Gordon-States Alan Heath Malin Keal Ian Phelps Lee
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