Solar Rotation Nos: 2230 to 2231
Almost no sunspots visible but there was more to see in the red light of hydrogen-alpha. The generally sunny weather meant lots of solar observations came in.
Here are the solar highlights for May 2020 together with a selection of images.
Sunspots
The Sun was spotless throughout nearly all of May though AR2760, AR2762 and AR2763 might just have been visible on the 1st but nearly everyone in the Section saw a blank solar disc every day in May. Solar faculae were seen on the 18th and on the 29th.
AR2764 just came into view over the NE limb on the 31st but it was not widely noticed.
SPA Sunspot Mean Daily Frequency: 0.01 (was 0.28).
SPA Relative Sunspot Number: 0.10 (was 3.18).
Solar Prominences, Plage, Filaments and Flares
There was more to see in hydrogen-alpha. Quite a few small interesting prominences were seen throughout the month, but some really stood-out.
A fine arch-type prominence appeared on the SE limb on the 2nd with an attached filaprom (part filament/part prominence) seen curving from the limb onto the solar disc. The arch prominence persisted a couple of days up until the 4th.
More small prominences were seen on the 5th and 6th particularly along the west limb.
A detached prominence was seen some distance off the north limb on the 10th.
An interesting prominence was seen on the NE limb on the 14th.
Another arch-type prominence appeared on the north limb on the 24th along with two flame -type prominences on the west limb. The following day the arch had become two flame-like prominences (one of these being clearly detached from the solar limb). By the 26th the prominence had become a single long flame detached from the NW limb.
A few small filaments were seen on the solar disc throughout May. Areas of bright plage but none developed into sunspots. Plage were seen every day in various locations from the 20th until the 26th. Several short filaments and bright plage with a small number of low-lying proms were seen clustered around the NW limb on the 27th. By the 28th these had all gone but there was a string of several short filaments seen along the northern hemisphere.
A small filaprom was seen on the north limb on the 30th and there were several other prominences to see.
No solar flares were reported in the Section but Spaceweather.com highlighted three fairly minor solar flares (C-class and M-class) just over the solar limb on the 29th, and remarked on them as being the strongest flares detected since 2017.
SPA Prominence Mean Daily Frequency: 2.60 (was 1.44)
Congratulations to Michael Fullerton who observed 31 days in May. Brian Gordon-States, Alan Heath and Jonathan Shanklin were all just a day behind on 30 days each.
Detailed count records of Active Regions and Relative Sunspot Numbers came from: John Chapman-Smith, Brian Gordon-States, Michael Fullerton, Mick Jenkins, Ian Lee, Lee Macdonald and Bob Steele.
Images and drawings were supplied by: Mark Beveridge, Paul Brierly, Carl Bowron, Alan Clitherow, Kevin Kilburn, Ian Lee and Cliff Meredith.