Some stunning H-alpha sights on holidays

[michael.h.f.wilkinson]

Apart from several night-time sessions, I had several day-time looks at the sun with the eminently portable Lunt LS35THa, much to the delight of many at the campsite in France this last summer. All observations were done with the Pentax XF 8.5 mm EP. Here is my summary of the main events:

July 26: Massive prominence visible on the northern part of the eastern limb. A huge arc of twisted plasma looped north to south. Several other prominences spotted, along with a few sunspots, and dark strands snaking their way across the disk.

July 29: Much more quiet, with several smaller prominences, one resembling a broken tree trunk on the eastern limb

July 30, 19:30 : big compound arc on eastern limb on 9 o'clock position, smaller arc to north (11 o'clock). Several dark strands snaking across the surface, a few small prominences on the western limb, and a couple of sunspots visible

July 31, 17:45 to 20:00: Two large prominences spotted fairly close to eachother on the eastern limb, just south of equator, resembling two waves craching towards eachother. Several smaller prominences on the western limb, and at least three sunspots or groups, and dark filaments visible on the disk. After about 5-10 minutes after my initial view I had the distinct impression that a filament was extending from the southern of the two "crashing waves" northwards. Frank (my eldest, 10) and I took turns looking at the changes, and slowly watched the filament grow, until it linked up with the northern (which also seemed to twist and change shape) to form a complete bridge. Closer inspection showed that the northern part emerged from a spot just on the closer side of the limb, whereas the southern part seamed rooted either on the limb, or just beyond.

At about 19:10 a very bright spot developed in one of the active regions just east and a bit south of the centre of the disk. This vanished just some ten minutes later. The last observations showed the two prominences had formed a complete arc, and a southward pointing branch was starting to develop. I calculated tha about 150,000 km had been covered in about 7,500s, giving a speed of some 20 km/s (fast but not startling in astronomical terms), assuming the velocity along the line of sight was zero.

I have never seen the sun behave so dynamically in such a short time span.

[rory]

nice report michael. ive never looked at our star yet. would like to have a go sometime ,especially as theres so many washed out nights.

[michael.h.f.wilkinson]

Yeah, it is nice to be able to do some daytime observing. Doubles the chance of having a look (or doubles the chance of clouds if you believe in the great prophet Murphy )

[Guest]

nice report.

the fact is in july between the 26th and the 31th of july, the sun was active but not to many.

i took pictures of the prominence of sun when i was in france (provence).

arnaud