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Sun 21-7-2012 Ha + CaK

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The bright thing in the sky appeared again. So I shot it.


Baader CaK + ND5 filters, DMK41, Canon 100-400L


Sun 20120721 Ha by Crestie Crazy, on Flickr

DMK41, Celestron X-Cel 2x barlow element, Coronado PST

Trying avistack for first time today so both stacked by it. Wavelets applied in Registax 5.1, finish in PSE9. Both files were just over a minute for over 1000 frames each. I have no idea what I'm doing in avistack but have now found the full auto mode. That'll do for now! This is now my best ever detail level in H-alpha.

Still got a LOT more data to go through! Will concentrate on the Ha data, due to field of view limits with the barlow, I have to do the sun in two halves. So I've got two sets for prominences and another one for surface to go, then the nightmare of blending it that I never got working well... The CaK data still isn't sharp... in part this might be reaching the limits of the 100-400L and I need to get a bigger scope on the job, once I've ordered the appropriate mounting bits.

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CaK is always difficult due to the shorter wavelengths.

Your images show great promise, no need yet to go for larger aperture...just go easy on the wavelets - they look a little over cooked.

Onwards and Upwards

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Optically speaking, I thought the shorter wavelengths would actually help by delaying the onset of diffraction effects?

Am I overcooking the wavelets? I am wondering if this might be a case of something I don't or can't see yet... I know I'm not there yet on the CaK one, with the wavelets not doing much at all unless turned up to 11. I am quite happy with the H-alpha one though, putting aside I haven't started tackling the prominences separately yet, or the missing half...

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I have my wavelets settings stored as a RMV files (registax wavelets file) - this I use as the starting point on each and every solar image that I take. On most of them I don't do anything else in Registax.

I can mail it to you if you want to give it a go?

I've never had a go with a CaK scope, so cannot help... But the Ha one looks good, if it was a DSO image I'd say you'd over sharpened, which I guess would be the wavelets...


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Thanks for the offer, I'd like to give that a try.

I did process this as if I was doing terrestrial photography, where I aim for a reasonable of apparent sharpness at pixel level without introducing artefacts like excessive contrast or halos. And this was the first time I had data capable of providing that... after my tinkering with wavelets I applied further fine sharpening in PS.

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It was a bit of a miracle to see the sun again and you got some fabulous pictures, well done :)

I think what Merlin means about the wavelets is, if you see a white edge with a black halo next to it in your image you have pushed a little far. As soon as you see this effect, edge back until it just disappears, then you have the wavelets perfect.


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It's been near enough clear all yesterday and today so far.

As for the wavelets, I know about clipping and generally it isn't a problem except on the limb where it seems no matter what setting I use I get the ringing (similar to using unsharp). The only way to prevent that is to back off so far you don't get any significant benefit elsewhere. I suppose I could try a blend optimised for different areas...

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Hi Stephen,

Thanks for sending me over the Tif. I've had a bit of a play - it's lovely to have a bigger file to play with - I love the DMK21, but the images are on the small side.

Here is my attempt at processing.

1. I used my standard Wavelets Scheme in Registax5.

2. Then into PS, carefully (I didn't do it carefully enough) mask around the solar disc.

3. Then invert selection, copy. (delete selection from background layer).

4. Create another layer and paste

5. I then use my "Colourise Sun" action on both the prom layer and disc layer.

6. Did some small curves adjustments on the prom layer.

Save as JPG

Cheers Stephen, enjoyed that :)


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Yup, you definitely bought out the prominences. Think I'll have to try that. I also got some data exposed for the proms, but then I have the fun of re-integrating them...

Part of why I went for the DMK41 over the smaller/faster ones was the size. Coming from a SLR background, all astro sensors that have a sane price tag seem really small to me! I know in this specific application, the data transfer bandwidth will limit things, but still...

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