AR12720 in H alpha

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p_zetner
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AR12720 in H alpha

Post by p_zetner »

Hello Everyone.

Here is the (rather meagre) yield of my imaging session on August 26. I was very excited to get a chance at the two prominent active regions, the big filament and a set of bright E limb prominences with my C8. The forecast called for sunny skies in the morning with quite good seeing predictions (Xasteria). Pre-dawn skies were splendidly clear so I set up the scope for some thermalization time, activated the Daystar heater and took my favourite four footed mammal for a walk. Returning to the rising sun, I began the exercise of focusing under seeing conditions that weren't horrendous and promised improvment. Then, the laptop screen started darkening and I noticed the leading edge of a hideous cirrus cloud layer racing to cover the Sun! So much for the clear sky forecast. Three hours later, the cloud cover was thinning and it now became a race to beat the approaching shadow of the large pine next to me. I managed to record at a furious pace, focusing only on the beautiful dipole AR12720. By now the seeing had significantly deteriorated so focusing was hit and miss Stacking 20 out of 6000 frames (!), this is what I ended up with. I'm not sure if I'm finished with processing but I'll post anyway. (Beautiful clear skies for the rest of the day as the Sun moved completely out of view of my scope!)

Cheers, Peter.
2018-08-26-094619-final-noise-shrp-lvls.png
2018-08-26-094619-final-noise-shrp-lvls.png (1.57 MiB) Viewed 1158 times
2018-08-26-094619-final-noise-shrp-inv-lvls.png
2018-08-26-094619-final-noise-shrp-inv-lvls.png (1.6 MiB) Viewed 1158 times


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Re: AR12720 in H alpha

Post by MalVeauX »

Nice Peter, very ethereal!

I can't imagine trying to focus at 8,000+ mm focal lengths!

Very best,


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Re: AR12720 in H alpha

Post by p_zetner »

Thanks, Marty.

Part of that ethereal quality probably came from trying to focus and image through milky sky :)

You’re right. I’m always amazed that focusing at 8 to 9 metres isn’t a total washout. When the seeing is good, though, you can really notice a position of best focus. It doesn’t snap into view like it would for a fast scope but it’s way better than I expected for ~f46.

Another thing that always amazes me is the fact that you can pull finer detail out of an image at f46. The Airy disk diameter is about 14 pixels for my camera...... oversampled by a factor of seven! That’s the miracle of deconvolution and sharpening, I suppose.

Cheers, Peter.


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Re: AR12720 in H alpha

Post by p_zetner »

Thanks, Franco.

Like I replied above, the milky sky may have contributed to the soft look!

I do try not to overprocess but sometimes end up losing some detail. Still struggling with the processing workflow.

Cheers, Peter.


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Re: AR12720 in H alpha

Post by ffellah »

Really good results taking into consideration the very challenging conditions, Peter ! Plus, this is a pretty amazing close-up. I like your "soft" processing, without too hard a contrast and sharpening.

Franco


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Re: AR12720 in H alpha

Post by Carbon60 »

It's a pity about the seeing, Peter. Your session sounds almost exactly like mine this weekend; the seeing conditions not really up to hi-res work and a bank of clouds rolling in, making everything a bit of a rush.

Good result, nevertheless.

Stu.


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Re: AR12720 in H alpha

Post by Montana »

:) sounds like a solar imaging morning at my house :lol: it really is not funny at the time though.

You still got a stunning image :bow I had rain all weekend :(

Alexandra


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Re: AR12720 in H alpha

Post by bart1805 »

If this is the image after stacking 20 images, your focus was spot-on! I really like the image and am curious how it looks when you stack 100 or 200 images.


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