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M57 HaRGB


carastro

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Data collected over 3 different years.

DSLR in 2011 15 x 5mins  from SE London

Ha 2015 6 x 900secs Atik460 and ED80

Ha 2017 4 x 15mins + 1 x 20mins  ED120 and Atik314L

I don't think I have good enough resolution to get much better detail than this even if I collect a lot more data.

Carole 

  Modified 450D

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How interesting to have combined different images from three different cameras.  Looking at the bright stars on the left side of the image, you've  got some mismatch between the different colours haven't you. Assuming that's in the processing is there a way to get rid if that? Might sharpen the image a tad if you could. 

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Thanks.  I can't really see anything different on the left side to the right side.  Maybe it is more to do with different size stars in the RGB, I'll take another look.

Carole 

 

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5 minutes ago, carastro said:

Thanks.  I can't really see anything different on the left side to the right side.  Maybe it is more to do with different size stars in the RGB, I'll take another look.

Carole 

 

Actually it's on both sides now I take a closer look. It's just that there are more big stars on the right side. Expand the image and you'll see a mis-registration of the blue and yellow parts of the stars. It's a diagonal mismatch across the star - top left blue through bottom right yellow. 

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Might sharpen the image a tad if you could. 

Have done a High pass filter on it to sharpen it a bit.   I've also doubled the resolution so you can see it better.  Some-one on Astrobin mentioned seeing the faint trace of an outer outer halo which I hadn't even noticed.  It's definitely very faint though.  

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Yes, I can see the outer halo now you mention it. It's a very nice image.  I still wonder whether there's more to be squeezed out of it if you could correct the misregistration (or whatever it is) of the red (purple) and yellow parts of the image. I've expanded one of your stars to show what I mean. 

 

image.png

Edit: oh, sorry. It's no bigger. Trouble is I'm trying to do this on an iPad. Duh! 

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 if you could correct the misregistration (or whatever it is) of the red (purple) and yellow parts of the image. I've expanded one of your stars to show what I mean. 

Thank you for badgering me into doing this.  I took a look at the files, and it was a problem with the original colour image done back in 2015 that I now just added the Ha to.  I split the channels and found it was in the blue filter, there was nothing wrong with the Registration.  I have done a correction to this, and also taken the opportunity to shrink the stars a little.

Hope this is better.

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Carole 

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The stars are definitely better aren't  they. Sorry!!! I was concerned you might think I was badgering you. I just felt there was more to be had in the image. I must have a go at M57 myself one day. :)

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Thanks Ouroboros and RonL.

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I can very faintly make out the outer rim halo , very faint tho

Some-one on Astrobin also mentioned that, and I hadn't noticed it myself, so that was a bonus.  I wonder what length subs I need to do to get that outer halo.  

That's OK Ouroboros, I needed the shove.

Carole 

 

 

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The improvement has made all the difference.

In an image like this you don't have to stretch the B-Jesus out of the stars just because you are stretching the B-Jesus out of the main target. By using layers in Ps you can have gently stretched stars and hyperstretched DSOs.

Olly

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Thanks Olly, I think this target suffers through being such a small object - at least with my kit - and having to zoom right in to get a decent view, therefore the stars and any slight discrepancy (such as focus) will be exaggerated, so I guess this enlarges the stars at the same time. 

I use some of the processing techniques you showed me all the time such as the selective layering and how to make stars smaller.  

Carole 

 

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