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Solar Highlights for March 16

Solar Rotation Nos: 2174 to 2175

With very low levels of sunspot activity, we are seeing the same level of solar activity seen previously in early 2015 and before that in late 2013. There were more sunspots on the northern hemisphere of the Sun. There were very few solar flares. There was, however, a total solar eclipse this month but sadly not visible from the UK or Europe.
  
Here are the highlights for March 2016 together with a selection of images.

SUNSPOT SUMMARY 

As we went from February to March the recent sunspot activity of Active Region (AR) 2506 was still visible on the southern hemisphere of the Sun but it was beginning to fade from view. AR2506 was seen near the West (W) limb around the 6th.

This left mostly small sunspots visible on the disk especially near the East (E) limb where we had a trail of sunspots: AR2510, AR2511, AR2512 and right at the end AR2513 which was the nearest to the E limb having appeared over it on the 3rd. These sunspots, all on the northern hemisphere, were seen across the solar disk over the next few days and were still visible as the much anticipated total solar eclipse took place on March 8th/9th. This eclipse was not visible at all from the UK or Europe, but if you were on one of the many islands within Indonesia or you were on board a ship in the Pacific Ocean, you would have been able to see this wonderful natural event in all its glory (weather permitting).

The Sun remained quiet over the next few days but AR2519 had appeared over the E limb on the 10th and were joined on the 13th by AR2520 and AR2521 both appearing on the solar disk preceding AR2519. All of these were again on the northern hemisphere of the Sun. AR2520 quickly disappeared and had gone next day, but AR2519/20 remained on view until they went over the W limb around the 20th. By then AR2524, a pair of sunspots also on the northern hemisphere, were already quite a long way onto the solar disk and nearly at the Central Meridian (CM).  It was classed as type Eho on the 20th and while it did develop a little more it was still much the same as it headed towards the W limb (it was classed Eso on the 25th).

AR2526 appeared over the E limb on the 25th and was classed as a type Hsx on the southern hemisphere. Over the last few days of March we had AR2524 nearing the W limb and AR2526 leaving the E limb (AR2525 had come and gone on the 24th). AR2526 did develop a little on the 30th as it crossed the CM and was the only sunspot visible by then.

If you want to know more about the sunspot classification, see the guidance on our website at: http://www.popastro.com/solar/solarobserving/chapter.php?id_pag=358

SPA Sunspot Mean Daily Frequency (MDF): 2.65 
SPA Relative Sunspot Number: 32.07

PROMINENCES, PLAGE, AND FILAMENTS
   
In contrast to sunspot activity there was more to be seen in hydrogen-alpha especially towards the middle of March when we saw plenty of prominence activity around the solar limb (edge) and plage and filament activity on the disk itself.

1st and 2nd saw a beautiful tree-like prominence on the W limb and plage activity associated with AR2506.

Later in the month, on the 14th, another large prominence was observed but on this occasion on the SE limb. Later the same day this prominence was seen to have developed further and was now attached to a filament on the solar disk (creating a “filaprom”) near the E limb.

The 17th saw lots of activity. There were several prominences around the limb but the disk showed plage activity around AR2519 in the west and extending along the Sun’s disk towards AR2524 in the east. However, the 19th was exceptional for prominence, plage and filament activity. The NE limb was full of prominences as was the SW limb but in between across the surface of the Sun could be seen several long dark winding filaments with extensive plage activity around AR2519 and AR2524. AR2524 continued to show impressive activity in H-alpha over the next few days.

Towards the end of the month, as AR2526 was seen crossing the Sun, there was plage activity seen around it plus much farther south, two dark filaments separated from the sunspot. These filaments seem to broaden and darken in appearance over the next few days as we came to the end of March.

SPA Prominence Mean Daily Frequency (MDF): 5.05

Well done to Brian Gordon-States who observed the Sun on 26 days in March. Jonathan Shanklin observed on 21 days and Alan Heath was not far behind on 20 days. Not easy with the continued cloudy weather we have experienced lately!

Detailed count records of Active Regions and Relative Sunspot Numbers came from: Brian Gordon-States, Alan Heath, Mick Jenkins, Ian Lee, Lee Macdonald, Jonathan Shanklin.

Images and drawings were supplied by: Carl Bowron, Mick Jenkins, Ian Lee, Cliff Meredith, Brian Woosnam and Julia Wilkinson.

Geoff Elston

Director
 

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