Contains:  Solar system body or event
Solar surface and prominences in Ha: 25 minutes’ animation and a short review of my 1st processing with ImPPG, Rick Veregin

Solar surface and prominences in Ha: 25 minutes’ animation and a short review of my 1st processing with ImPPG

Acquisition type: Lucky imaging
Solar surface and prominences in Ha: 25 minutes’ animation and a short review of my 1st processing with ImPPG, Rick Veregin

Solar surface and prominences in Ha: 25 minutes’ animation and a short review of my 1st processing with ImPPG

Acquisition type: Lucky imaging

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Description

Capture and Animation Steps
My animation used brightness inversion on the solar disk, thus both prominences on the limb and surface (the latter are called filaments) will appear bright, as will surface sunspots. Seeing was just average and there was variable haze/transparency during the capture. But I learn something every time I image, so this is another learning experience.

This video of 10 frames was created from images taken on October 17th over  25 minutes. The individual frames of the animation were all from 60 second SER videos at 2600x2600 pixels in 16 bit mono (the camera is 14 bit) taken at 24  fps. Each video was separated by a delay of 60 seconds. The resulting 1400 frames were stacked in Autostakkert3 as the best 15%, so about 200 frames were used in each of the final animation frames. In Photoshop I used Tween to smooth out the animation and make the video a little longer—I had not planned it to be so short, but clouds had another idea. A shout-out to  @Ruediger  for showing me how to get Tween to work the way he was using it, and how I wanted to use it, when many places on the web were telling me you can't do that with Tween.

Review of Processing in ImPPG
For the first time I used ImPPG rather than Registax 3 for sharpening. First, since transparency was changing like crazy during the imaging, ImPPG can rebalance the WP and BP to match image brightness--no need to do it manually in Photoshop. What I really though was amazing about ImPPG is that I could do the surface grayscale inversion and bring out the prominences with the curves and, at the same time, optimize the Lucy-Richardson Deconvolution (sigma=2.3,500 iterations), as well as the unsharp mask (sigma=10, using the adaptive settings and a threshold not to overly sharpen fainter/noisier parts). This meant I could see immediately what the final image was going to look like and thus quickly optimize it. And it is very fast, even with full surface imagined at 16 bit and 1.5X drizzle, adjustments over the whole image were nearly instantaneous. All the settings can be saved and then a batch processing does all the images. Amazing!. The color and gif animation were done in Photoshop to complete the animation. 

I had first done Registax for this animation and did not like it at all, so I was super pleased by the way this turned out with ImPPG. In fact, the 3D quality in this image is better what I was doing in Registax, so I can’t wait to get some new data with better sky conditions. Of course, I'm not an expert in Registax (nor obviously in ImPPG), but right now ImPPG is winning in my hands.

And to top it off, ImPPG is free, and can be downloaded here . I used the older stable version, but there are newer Beta versions with some extra features that I have not tried yet.

My Layman’s guide to the “Top 10 things to see in Solar Ha.”
For those that missed my previous posts, I’m including again my list of the Top 10 things to see in Solar Ha. Our Sun in Ha has so many interesting features that it challenging to understand exactly what one is seeing.  I compiled this summary of as a viewing aid for myself, hopefully you may find it useful too.

My Layman’s guide to the “Top 10 things to see in Solar Ha.”
In white light we only see the Sun’s 6000 Kelvin photosphere “landscape”, consisting of:
•    Darker, cooler sunspots
•    Granulation, consisting of hotter and brighter rising; and cooler and darker sinking convention cells, like boiling porridge.
•    Faculae, bright hot patches of concentrated magnetic flux.

It is the chromosphere that shows up In Ha, as we block out the Photosphere’s overwhelming white light. The chromosphere is a much hotter, 2000 km thick layer, lying above the Photosphere. With temperatures rising to 17000 K, the chromosphere efficiently excites hydrogen to produce Ha emission. 
The chromosphere shows a very different “landscape” than the Photosphere:
•    Spicules, tiny bright spikes, form a 3,000-10,000 km layer of bright fuzz on the Sun’s limb, and darker spikes on the solar disk. They are dark on the disk as they are cooler than the chromosphere below them. Few last more than 15 min, but the Sun has 100s of thousands of them at any one time.
•    Fibrils are tiny low contrast darker filament-like structures. 
•    Dark Mottles, comprised of fibrils and spicules, blanket the entire disk. 
•    Field Transition Arches are groups of longer fibrils that join areas of opposite magnetic polarity.
•    Prominences loop out from the limb: these are glowing, but cooler, hydrogen gas lifted from the Sun by magnetic fields. Prominences rise 100s of thousands of km above the hotter chromosphere.
•    Filaments are the darker clouds that seem to float on the solar disk. Filaments are prominences, appearing darker because they are cooler and higher, extending above the hotter chromosphere below them.
•    Plage (French for beach) are irregular, bright patches on the solar disk, found around active regions. They mark nearly vertical emerging or reconnecting magnetic fields and can last several days.
•    Ellerman bombs (named for the astronomer who studied them) are tiny, brighter spots that fluctuate in brightness, associated with large plage.
•    Flares show a brightening within a sunspot group, often with a “comb-like” flow.  They last from a few minutes to hours and change in both intensity and area as you watch.
•    Sunspot umbrae are the dark cores of sunspots, much like what is seen in white light. However, sunspot penumbrae branch out into whirls consisting of fibrils and spicules. 

Bonus, not in the Top 10, because it is difficult to observe:
•    The Chromospheric Network is outlined by filigree, which are very tiny bright spots that are less than 1 arc-second in size, and best observed off-band of Ha.

Note that it is common to invert light and dark on the solar surface, which provides improved contrast for the solar disk, and a better brightness match to the fainter prominences. It also has the advantage that the otherwise dark filaments on the surface (which are prominences) are now bright, matching the bright prominences at the limb.

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