"the Iris Nebula or NGC 7023, is a reflection nebula. This means that its color comes from the scattered light of its central star, which lies nestled in the abundant star fields of the constellation Cepheus. Located some 1,400 light-years away from Earth, the Iris Nebula’s glowing gaseous petals stretch roughly 6 light-years across."
...Reflection nebulae glow because they are made up of extremely tiny particles of solid matter, up to 10 or even 100 times smaller than dust particles on Earth.... it includes large filaments of deep red, indicating the presence of an unknown chemical compound likely based on hydrocarbons. Studying nebulae like this one helps astronomers learn more about the ingredients that combine to make stars."
https://www.nasa.gov/image-feature/the-iris-nebulaThis is the first reflection nebula that I process with hours of data collected. In many senses was a big challenge as this fascinating nebula has a dust part that I was not sure would be able to pull out with the data we had. Maurizio acquired it in April and May 2020 and from our backyard in a Bortle 5-6 zone. Even with the filters there is always uncertainty in how well those details can be collected.
It was a nice 'hard' work. I stacked apart all the frames from each filter and then after I blended both once it was worked in level, curves etc.. Also did a starless version to work the dust and incorporated later the stars. The big issue I remember was finding some sort of 'moire' pattern present in the 2 drizzle stack of the Enhance filter. Not sure what was the problem but I remember I have to use a lot of noise reduction and blur for softness.
A first version was finished in October 2020 and I found it was very dark and almost the dust cannot be seen in the outer part around the core. In December 2020 I reworked it again to pull more dust out and turn the background less dark.
We liked the result obtained with this reflection nebula but we wish to get back on this again as it is a very special not only the dust around all the area is very wide and we like very much the images of several astrophotographers that has done a nice work on that (investing a lot of hours) but also bring out more of the spectacular details of the core revelled by its central star, a magnitude +7 star, SAO 19158.
The special colour this reflection nebula has is one of the few out there and the way that is reflected on the dust gives an impressive perspective when you can see the stars behind and through the dust.
Version 1 Process Oct. 2020 and Version 2 Dec. 2020
https://twitter.com/AstroOtus/status/1321048426193293313https://twitter.com/AstroOtus/status/1334884989830369281
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