Solar Activity 21 Jun

[brianb]

The last morning of Spring was dull & grey but the sky started to clear during the first afternoon of Summer.

Active area 11082 remains the only "white light" feature and practically the only feature on the disc in CaK:

1349 UT. Coronado PST CaK, prime focus, DMK41

1402 UT. Solarscope 60, 2.5x Powermate, DMK21

1430 UT. WO FLT 110, Lunt solar diagonal, 2.5x Powermate, DMK21

1421 UT. Lunt 60mm, B1200 CaK diagonal, 2.5x Powermate, DMK21

The Ha overview shows a significant filament near the east limb

1355 UT. Solarscope 60, 0.5x focal reducer, DMK41

1407 UT. Solarscope 60, 2.5x Powermate, DMK21

and numerous small prominences scattered around the limb (the largest was on the north west limb)

1444 UT. Solarscope 60, 2.5x Powermate, DMK21

1447 UT. Solarscope 60, 2.5x Powermate, DMK21

1439 UT. Solarscope 60, 2.5x Powermate, DMK21

1442 UT. Solarscope 60, 2.5x Powermate, DMK21

Transparency initially poor with patchy cirrostratus (spreading contrails) but improving to good. Seeing moderate but deteriorating with increasingly strong boiling. Temperature 19C, wind SE force 3-4.

[GuillermoBarrancos]

You seem to have better seeing conditions than me.

Plus, WO FLT 110, Lunt solar diagonal, 2.5x Powermate, DMK21 makes a difference too I guess. Compaired to my MS LifeCam HD.

Maybe you could tell what settings you use in Registax 5.1? I use the default settings. Maybe I'm doing something wrong there and will be able to get more out of my avi's.

[Mark at Beaufort]

Thanks Brian for postings these great solar images. I viewed the sun yesterday and thought I could detect a smaller spot between the two that had been visible for a while - your photo confirms.

The image quality through the Lunt herschel wedge is really impressive.

Mark

[george7378]

I can't wait to go and have a look!

[brianb]

Maybe you could tell what settings you use in Registax 5.1?

I don't often use Registax for solar work, I almost always use Avistack instead. (The exceptions are prominence images taken in variable transparency, which Avistack doesn't cope with well. And I use Registax for planetary work.)

Most of the quality comes from (a) not using too long a focal length and ( getting the focus right. When the seeing is bad enough to make focusing difficult, I tend to "bracket" focus - shooting three or more AVIs with the focus inside, on & outside what I judge to be the best focus. There's a balance between gain, exposure time & number of frames which you need to learn for yourself ... usually I shoot 2000 frames & stack 400 but with bad seeing I will often increase the gain slightly to get a faster exposure, shoot 3000 frames & stack 500.

The Avistack settings are remarkably close to default. The main changes are to increase "minimum distance" to 24 - this reduces the processing time hugely without hitting image quality noticeably - and reduce the percentage of frames accepted. I go fairly light with the wavelets & sometimes apply a bit more sharpening in post production (PS Elements).

Hope that helps.

BTW my first efforts were pretty ropey, you do get better with more practice ... time to think about upgrading equipment when your results are pretty good & plateauing.

[GuillermoBarrancos]

Thanks! I will have a look at Avistack.

I guess with the difficulty in focussing is that the image constantly goes in and out of focus due to boiling.

Making it hard to hit the sweet spot with focussing.

But yesterday the seeing was pretty bad anyway for imaging, due to faint cloud cover. So it wasn't really clear to begin with.

I also will try to shoot at a lower (640x480) resolution, so I can capture at 60fps and maybe get some better frames out of it.

[Briggsy]

Fascinating photos

[george7378]

Here are my photos of 1082 for today:

[GuillermoBarrancos]

Well. It seems Avistack doesn't like Windows 7, as it keeps crashing with the avi codec.

EDIT: Weather cleared up a bit, so I captured some more avi's in mjpg format, instead of yuy2. And now Avistack seems to cope a lot better.

Shame it cannot handle yuy2.