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Solar Highlights for June 16

Solar Rotation Nos: 2177 to 2178

June saw a very low level of sunspot activity. On most days many saw few sunspots and on two occasions many observed no sunspots at all. Hydrogen-alpha was slightly better.

The Summer Solstice occurred on June 21st marking the longest day for those of us living in the northern hemisphere and the shortest day for those living in the southern hemisphere.

Here are the highlights for June 2016 together with a selection of images from members of the SPA Solar Section.


At the beginning of the month we sat AR2549, AR2550 and AR2551 nearing the (W) west solar limb. The first of these Active Regions was on the northern hemisphere while the other two were both south of the solar equator. They had all gone by the 4th leaving virtually no sunspots visible for several days.

It was the 8th before a small, but developing, sunspot (AR2552) appeared on the solar northern hemisphere, near the W limb. As AR2552 approached the W limb it unleashed several minor C-class solar flares. It was joined by AR2553, a southern hemisphere sunspot. AR2553 came over the E limb on the 11th followed by AR2554 on the 12th. AR2553 was a fairly substantial Hhx type southern hemisphere sunspot. It remained much the same as it travelled across the solar disk until disappearing over the W limb on the 23rd. From then until the end of June many of us saw few or no sunspots for the second time this month.

If you want to know more about the sunspot classification, see the guidance on our website

SPA Sunspot Mean Daily Frequency (MDF): 2.12
SPA Relative Sunspot Number: 35.97


There was a bit more to see in Hydrogen-alpha light (Ha) with several small prominences on the SW limb on the 1st, 2nd and 3rd together with numerous bright areas of plage on the solar disk. Two filaproms were seen on the 1st on the west and north limbs, while a third was seen on the 2nd and 3rd on the NW limb.
As the sunspots disappeared there were a few small prominences and filaments still visible. Of note, was the 5th where there was some bowed plage and filament activity on the NE quarter of the disk, and on the 7th, 8th and 9th (around sunspot AR2552).

After the 12th as AR2553 was carried east to west by the Sun’s rotation there was an upturn in plage and filament activity around or near to AR2553 and AR2554.

By the end of the month as the sunspots once again faded away, we saw more in the way of prominences and filaments. The 27th to 30th saw some interesting filaments and prominences on the E and NW including some filaprom on the E limb and the S limb.

Alan Heath observed three solar flares:

6th at 1015UT, following limb, east, south;
9th 0830UT to 1300UT (brightening), gone by 1400UT;
16th at 1330UT.
SPA Prominence Mean Daily Frequency (MDF): 4.71

Well done to Brian Gordon-States who observed every day in June. Jonathan Shanklin observed on 28 days and Alan Heath 25 days.

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

Images and drawings were supplied by: Mark Beveridge, Carl Bowron, Paul Brierley, Mick Jenkins, Ian Lee, Cliff Meredith and Julia Wilkinson.

Geoff Elston


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