IC1318 Nebulosity around Sadr in Cygnus HaRGB

[gorann]

I managed to catch a bit over an hour of RGB with the ASI071 (on Esprit 150 and Mesu200) last night before the clouds rolled in, so I could add it to my Ha data prebviously posted. Most of the RGB is 5 min exposures but I also added some 60s and 10s exposures to save Sadr - the very bright star in the centre of Cygnus and to the left in this image - it was completely blown out in the 5 min exosures. I added Ha to the red channel and I used something like a tone mapping approach (blurring out the stars of the RGB data) since the RGB stars were big, then I used Ha again as lum and I subsequently added the stars separately by selecting them in the Ha image and use the selection to cut them out of the RGB image. Sounds a bit complicated and it was. In that way I preserved the sharpness of the Ha data and kept the stars small. All done in PS of course except initial stacking and calibrating in PI. Now totally 8.8 hours.

Any comments much appreciated - I have the feeling the image could be improved but not sure how.

 

 

 

Edited September 26, 2019 by gorann

[gorann]

Tried some HDRM in PI and added a touch of that as a layer in PS. It did add a bit more dynamic especially to the brighter parts.

[Rodd]

Hello Goran....To me, it looks opaque-ish, not like gas and dust--more like clay that has been sculpted.  Not sure what work flowe you used--a lot of noise reduction?  I do like the palette.

Rodd

[gorann]

1 hour ago, Rodd said:

Hello Goran....To me, it looks opaque-ish, not like gas and dust--more like clay that has been sculpted.  Not sure what work flowe you used--a lot of noise reduction?  I do like the palette.

Rodd

Maybe it could be because it is a HaRGB image and not one of the ver gassy NR images of this object, But I will think about it....

[Rodd]

8 minutes ago, gorann said:

Maybe it could be because it is a HaRGB image and not one of the ver gassy NR images of this object, But I will think about it....

I don't think that is it.  Here is a crop of a tiny area as an example--this is a huge crop so pardon some thing s such as star profiles and things like that--its way to far in to be useful as an image--but it is good for my purpose of demonstration.  This is HaRGB as well--taken at 318mm FL (hence the huge crop). I won't try and verbalize my point--the image should do that on its own--after all no desire to write 1,000 words (as in an image being worth 1,000....ya know).  Anyway--to me, IMO, there are regions of your image that are difficult to visualize depth.  One thing I note is the dark structures in yours tend to be wide, lacking in some of the find tendril like features--hence why I asked about noise reduction.  Anyway--just some CC--if its useful, great, if not....no harm

Rodd

 

[gorann]

16 hours ago, Rodd said:

I don't think that is it.  Here is a crop of a tiny area as an example--this is a huge crop so pardon some thing s such as star profiles and things like that--its way to far in to be useful as an image--but it is good for my purpose of demonstration.  This is HaRGB as well--taken at 318mm FL (hence the huge crop). I won't try and verbalize my point--the image should do that on its own--after all no desire to write 1,000 words (as in an image being worth 1,000....ya know).  Anyway--to me, IMO, there are regions of your image that are difficult to visualize depth.  One thing I note is the dark structures in yours tend to be wide, lacking in some of the find tendril like features--hence why I asked about noise reduction.  Anyway--just some CC--if its useful, great, if not....no harm

Rodd

 

 

I think the differences may relate to how these images were processed. Because I had quite a lot of Ha data but only about an hour of RGB data (due to clouds rolling in and they are still here) I did a kind of tone-mapping procedure where I blurred the RGB data so it would not bring noise to the image and then used Ha both in the red channel and as Lum. That will produce a rather different image than if I only added Ha to the red channel in a RGB image. It will be a more Ha based image. If I get more RGB data I may try the more classical approach.

Here is a different version where I brightened up the background a bit and reduced contrast using curves. Looks a bit more like your version. I noticed that your Sadr looks bluish on my screen while mine is more yellowish. So I had to look it up and Wiki says "characteristic yellow-white hue of an F-type star."

 

Edited September 28, 2019 by gorann

[Rodd]

8 hours ago, gorann said:

I think the differences may relate to how these images were processed. Because I had quite a lot of Ha data but only about an hour of RGB data (due to clouds rolling in and they are still here) I did a kind of tone-mapping procedure where I blurred the RGB data so it would not bring noise to the image and then used Ha both in the red channel and as Lum. That will produce a rather different image than if I only added Ha to the red channel in a RGB image. It will be a more Ha based image. If I get more RGB data I may try the more classical approach.

Here is a different version where I brightened up the background a bit and reduced contrast using curves. Looks a bit more like your version. I noticed that your Sadr looks bluish on my screen while mine is more yellowish. So I had to look it up and Wiki says "characteristic yellow-white hue of an F-type star."

 

That may be true.......still, for what ever reason. And yes. They is why I said mine was not a good image. I had not gotten sadr very well. I got it good in my sho though.   This image looks much better

Edited September 28, 2019 by Rodd

[gorann]

3 hours ago, Rodd said:

That may be true.......still, for what ever reason. And yes. They is why I said mine was not a good image. I had not gotten sadr very well. I got it good in my sho though.   This image looks much better

I think we are telling different "stories" in our images, as Adam Block calls it. In my image I have emphasized the complex structure in the underlying red nebulosity while you have emphasized the structure of the dark nebulosity on top. I think both "stories" have their merits.

[Rodd]

1 hour ago, gorann said:

I think we are telling different "stories" in our images, as Adam Block calls it. In my image I have emphasized the complex structure in the underlying red nebulosity while you have emphasized the structure of the dark nebulosity on top. I think both "stories" have their merits.

The underlying structures comes from the Ha for the most part, and the dust/cold gas regions.  I suppose one can skew an image in any direction and say “this one shows the green channel structures” or “this one shoes the blue channel structures”.  I guess I just don’t “get it”.  Though regardless of all this, the dark structures, which are in all channels (or more accurately not in all channels) should appear sharp and fully resolved, no?

Rodd

 

Edited September 28, 2019 by Rodd

[gorann]

10 minutes ago, Rodd said:

The underlying structures comes from the Ha for the most part, and the dust/cold gas regions.  I suppose one can skew an image in any direction and say “this one shows the green channel structures” or “this one shoes the blue channel structures”.  I guess I just don’t “get it”.  Though regardless of all this, the dark structures, which are in all channels (or more accurately not in all channels) should appear sharp and fully resolved, no?

Rodd

 

Not sure what you mean by fully resolved Rodd - nothing in our images are fully resolved since we are limited by both sky, exposure time and equipment, but probably most often sky. However, we have the choise to emphasize different aspect, for example by the way we stretch different parts of our images. There is no way we can show all the dynamic information in our data in a single image - we always have to make a choice and that is what I like about AP - you can make many interpretations of the same data. Adam Block makes some good points about it in this presentation:

 

 

[Rodd]

9 minutes ago, gorann said:

Not sure what you mean by fully resolved Rodd -

The dark structures in your original image were soft and laked fine scale definition, as I mentioned.  The thread like filaments adn lace like features.  That to me is apparent.

Rodd

[gorann]

14 hours ago, Rodd said:

The dark structures in your original image were soft and laked fine scale definition, as I mentioned.  The thread like filaments adn lace like features.  That to me is apparent.

Rodd

Now I processed the Ha layer with less contrast and added it as lum. This is as filamentous I can make my data. It is different and maybe better.

 

Edited September 29, 2019 by gorann

[Rodd]

16 minutes ago, gorann said:

Now I processed the Ha layer with less contrast and added it as lum. This is as filamentous I can make my data. It is different and maybe better.

 

There's the Goran I know!!!!  That is a stunning image.

Rodd

[gorann]

Just now, Rodd said:

There's the Goran I know!!!!  That is a stunning image.

Rodd

Thanks Rodd - maybe I was a bit stubborn on this one😉

[Rodd]

1 minute ago, gorann said:

Thanks Rodd - maybe I was a bit stubborn on this one😉

No worries...I am sure there is a truth in what you were saying.  Perhaps I failed to appreciate it and couldnt accept anything but the standard approach.   Set in my ways perhaps.  

on a different note, everytime I look up at Cygnus and Sadr in particular, I find it icredible that the star is literally embedded in the surroundings depicted in this image---and we can't tell.  Amazing stuff

Rodd