Cocoon Nebula

[symmetal]

It was fairly low in the sky around 30 to 35 degrees altitude but thought it was worth a try while it's visible in astro darkness, but it has turned out better than I hoped. 

There are so many stars, the background is hard to determine, so I tried the method posted by @Fegato of doing star removal before DBE and putting them back right after. This worked very well and revealed far more dust than is visible in the normal image. For BlurXTerminator I this time disabled star sharpening which preserved the star colours better. StarXTerminator was used again before separate stretching. Processed in PI and PS.

I kept the dust fairly muted as in reality it would be swamped by the stars and not visible, apart from the very dark patches. There is a large faint red patch above the cocoon so maybe some Ha there.

2 hours of 2 min subs. RASA 11 and ASI2600MC on EQ8-R.

Alan

[Fegato]

Nice one!  Stars are manic in this area, but must admit I'm doing the DBE star removal thing with every image now, just makes it so much easier to see what you're doing.

[symmetal]

7 hours ago, Fegato said:

Nice one!  Stars are manic in this area, but must admit I'm doing the DBE star removal thing with every image now, just makes it so much easier to see what you're doing.

You also don't need to check each sample to see whether there are any stars enclosed either, so can quickly plonk them where you want with a larger sample box size. 🙂

On my laptop the image looks a bit dark so I'll redo it with a bit more oomph. 

Alan

[symmetal]

Here is is with a bit more stretching which reduces the effect of the nebula compared to the previous one, though it shows a few more red patches and more detailed dust. I've boosted the stars a bit more too, as in reality they dominate the image so should be more apparent. I've also redone the annotation to include the extra catalogues which I'd just noticed were available if you clicked the + button. 😁 The 'random' LDN placements is quite amusing. The actual dark areas aren't included. 😄

Which one do you prefer?

Alan

[ollypenrice]

There are many approaches to this target and yours emphasizes the dust as a source of reflection.  In other words we see the dust 'lit up' by starlight.  Normally, in images without a manic Ha input, the dust is only a source of obscuration.  Certainly, what your images gives, to me at least, is something I've never seen before.  I think it's genuinely outstanding.

Olly

[symmetal]

1 hour ago, ollypenrice said:

There are many approaches to this target and yours emphasizes the dust as a source of reflection.  In other words we see the dust 'lit up' by starlight.  Normally, in images without a manic Ha input, the dust is only a source of obscuration.  Certainly, what your images gives, to me at least, is something I've never seen before.  I think it's genuinely outstanding.

Olly

Thanks Olly. 😊 On the higher stretched one, the red patches do appear more like reflected starlight as you say, and not Ha. It was hard determining the overall background colour as virtually the whole image is composed of different coloured dust. There looks like more interesting structures off to the right too so a follow up mosaic image is worth investigating.

I now really appreciate having the RASA, as you can complete an image with acceptable noise, in just two hours. In my skies with so few clear nights, that's a real benefit. I have loads of unfinished targets taken with the FLT98, which is effectively redundant now as it's the same fl as the RASA11.  I could use it to generate a star layer for the brighter stars I suppose to reduce the diffraction artifacts from the RASA if I'm being pedantic. 😉 

Just for comparison here's the image quickly stretched without using star removal beforehand. 😲

Alan

[gorann]

1 hour ago, symmetal said:

Thanks Olly. 😊 On the higher stretched one, the red patches do appear more like reflected starlight as you say, and not Ha. It was hard determining the overall background colour as virtually the whole image is composed of different coloured dust. There looks like more interesting structures off to the right too so a follow up mosaic image is worth investigating.

I now really appreciate having the RASA, as you can complete an image with acceptable noise, in just two hours. In my skies with so few clear nights, that's a real benefit. I have loads of unfinished targets taken with the FLT98, which is effectively redundant now as it's the same fl as the RASA11.  I could use it to generate a star layer for the brighter stars I suppose to reduce the diffraction artifacts from the RASA if I'm being pedantic. 😉 

Just for comparison here's the image quickly stretched without using star removal beforehand. 😲

Alan

Oh, wow Alan, this is the clearest demonstration I have seen of how star removal have changed image processing! Now we can finally get behind the stars and see what is out there!

[symmetal]

29 minutes ago, gorann said:

Oh, wow Alan, this is the clearest demonstration I have seen of how star removal have changed image processing! Now we can finally get behind the stars and see what is out there!

Yes, I agree Göran. I'd have thought the background leftover, after removing the stars wouldn't have much to work with in this case, but there's plenty of detail visible. How much is interpolated data would be interesting to see. Doing star removal on linear data, with its smaller stars, is a big advantage here.

Alan