April 10, 2015: Lovely H-apha Lunchtime

[michael.h.f.wilkinson]

Had the scope (SolarMax-II 60) out during lunch together with a gaggle of our graduate students, and we were treated to a very nice display. The huge hedgerow on the eastern limb (9 o'clock for us) is gorgeous, and seemed to evolve during our half-hour break. On the northeastern limb (one o'clock), a huge prom is visible, but most of the action comes from a smaller but brightter bulge further south (2 o'clock). This morning it was just a bright lump, but now it seemed to be changing shape as you watched, showing mulitple surges of plasma bubling up and down. At one point it seemed to fire off a thin stream of plasma in the northeasterly direction, which soon detached and then dissipated. It then seemed to collapse a bit, only to reappear showing three stubby branches, which slowly expanded. A bit further south another small, faint detached prom was visible.

Several filament criss-cross the disk, and AR12320 shows up as a sunspot surrounded by a host of swirls and plage areas. South of the hedgerow a long filament crawls across the disk terminating in a big triangular prom. Lovely fillaprom!

[Floater]

 The huge hedgerow on the eastern limb (9 o'clock for us) is gorgeous, ... On the northeastern limb (one o'clock), a huge prom is visible,

OK, I thought I had this nailed from a thread some good while ago but perhaps I still need some (more!) help ...

I've been watching the hedgerow for the past couple of days and it's on the leading edge so surely that has GOT to be the western limb?! Also, it being at '9 o'clock' then how could it be on the east if the prom at 'one o'clock' is on 'the north-eastern limb'?

Now please don't think I'm trying to pick you up, Michael. In fact, if it was just a slip of the keyboard, so to speak, I'll be happy 'cos my mind will be at rest! it's just that some of the wonderful pics that you and other imagers share with us have varying perspectives and are often exactly the opposite to the views in my EP - which is fine 'cos I assume they have been deliberatley inverted - or, more disturbingly, have no relation position-wise to my views. Further, I often see other narratives that state things like 'east' and 'west' which don't correspond to my idea of those directions.

I repeat, this is not an attempt to be a classroom smarty and, if I may, I'd like to widen this response to include a question about the sun's rotation. As I view through the day the limb features rotate counter-clockwise around the disc - i.e. the hedgerow is at 9 o'clock, for example, early on and progresses to 6 o'clock later. Similarly, a prom at 2 o'clock moves to 12 o'clock later on. If the sun is rotating from NW-SE, as I understand it, how come they stay on the limb(s) and don't 'disappear' behind the disc and new features 'arrive'?

Please help a chap to get to sleep more easily at night ...

p.s. Great report, Michael. Views of the sun have been wonderful these past several days for me.

[Stu]

I think Mark did a diagram explaining all this. It confuses me every time!! I'll try to find it

[Stu]

This one. I think you posted in the thread so perhaps it doesn't help?? eeek!

http://stargazerslounge.com/index.php?/topic/221466-The-Sun%27s-Orientation-using-different-telescopes

[Floater]

You're right Stu, I did post in that thread and thought I had it sorted. Have to dash now but will look at it again later.

Thanks for your quick response and rush to my aid ...

[Stu]

One thing that confuses me is that my Quark and Herschel wedge appear to be different when according to this they shouldn't be!!

The east/west confusion relates to whether you are considering from the perspective of earth or the sun..... I think!!

EDIT: Just checked and the first paragraph is incorrect, they are the same orientation. DOH!!

[Floater]

Stu, I've revisited that thread now, thanks for linking it.

I still think I have the east/west thing sorted but would love to learn more about the rotation ...