The Helix Nebula

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Graeme
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The Helix Nebula

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The Helix Nebula. A planetary nebula in Aquarius. A cloud of glowing ionised gas floating away from the hot remains of a dying star. The Helix Nebula has sometimes been referred to as the "Eye of God" and the "Eye of Sauron".

I can't claim the credit for capturing this one. It was imaged in filtered narrow band hydrogen α oxygen iii and nitrogen ii light and offered up for processing by my old mate Rob from Brisbane. This is my attempt at processing his data:

Capture.JPG
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Last edited by Graeme on 12 Nov 2020, 20:26, edited 1 time in total.

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HansV
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Re: The Helix Nebula

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Nice!
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Rudi
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Re: The Helix Nebula

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Ionised gas. As long as it does not start floating towards earth. :grin:
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HansV
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Re: The Helix Nebula

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The Helix Nebula is about 650 lightyears from the Earth. So gas with the extremely high velocity of 10% of the speed of light would take 6500 years to reach us...
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stuck
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Re: The Helix Nebula

Post by stuck »

The image is great :thumbup: keep them coming!

For those of you struggling with the science bit:
Graeme wrote:
12 Nov 2020, 20:25
...imaged in filtered narrow band hydrogen α oxygen iii and nitrogen ii light...
try reading this:
https://www.atik-cameras.com/news/begin ... d-imaging/

Ken

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Graeme
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Re: The Helix Nebula

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The process also filters out a lot of light pollution so the final image is a lot less noisy.

The three files are layered in processing and allocated to the red, green and blue channels. Could be hydrogen α red, oxygen iii green and nitrogen ii blue but there are no rules really!

The Hubble Space Telescope creates those stunning images using the Hubble palette and allocates SII – Red, Ha – Green and OIII – Blue.

A lot of people here probably understand the physics better than I do but I find putting it into practice and producing the final image hugely entertaining!

Here's another explanatory link: https://astrobackyard.com/narrowband-imaging/

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Graeme

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Graeme
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Re: The Helix Nebula

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Here's a link to The Sky Searchers astronomy forum where I posted the image above.

If you fancy having a try at processing the image, feel free to download the data and give it a go.

https://theskysearchers.com/viewtopic.php?f=107&t=14445

You will need Photoshop or Gimp or something similar.

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Graeme

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Re: The Helix Nebula

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Beautifully done, Graeme! Kudos and keep 'em coming!
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Re: The Helix Nebula

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Graeme wrote:
13 Nov 2020, 13:26
...understand the physics...
It's been a while since I had to get my brain round hydrogen orbitals, electron decay and photons.

Ken

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Graeme
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Re: The Helix Nebula

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BobH wrote:
13 Nov 2020, 19:05
Beautifully done, Graeme! Kudos and keep 'em coming!

Thanks Bob, will do!

stuck wrote:
13 Nov 2020, 19:26
Graeme wrote:
13 Nov 2020, 13:26
...understand the physics...
It's been a while since I had to get my brain round hydrogen orbitals, electron decay and photons.

Ken

It's just capturing photons at different frequencies, turning them back into electrons, counting them and giving the number a colour! :smile:

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Graeme

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Re: The Helix Nebula

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Graeme wrote:
13 Nov 2020, 13:41
...
If you fancy having a try at processing the image, feel free to download the data and give it a go...
I realise this is more than just a tad overcooked but it was fun to learn how to combine the three mono images.
NGC7293_4web.jpg
Graeme wrote:
13 Nov 2020, 19:54
...
It's just capturing photons at different frequencies...
Yes, I realise how it works. I was more musing on how long it's been since I'd had to think about electron decay and emitted photons. If you ask my kids, I did my degree when dinosaurs roamed the planet :laugh:

Ken
PS sometimes my boys are a bit more forgiving and just ask me what it was like when I was a boy and I went out hunting mammoths with their Grandad.
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HansV
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Re: The Helix Nebula

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Oh wow, is that from the same source image(s)? Not bad for a dinosaur!
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stuck
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Re: The Helix Nebula

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HansV wrote:
14 Nov 2020, 15:59
Oh wow, is that from the same source image(s)?...
Yes, the link Graeme gives to theskysearchers gives you a link to a Dropbox folder that holds three TIFF files, one for each of the narrowband frequencies. I opened them up in my (dinosaur) version of PS and then pasted each one into a different channel of a new/empty image. I did it that way because, as yet, I've not figured out how to do that in my copy of Affinity Photo (which is bang up to date). I then saved this combined image as a TIFF, and then reopened it in Affinity Photo. In there it was then a case of messing with the levels, curves, contrast etc. on each channel.

Ken

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Re: The Helix Nebula

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It worked very well!
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Graeme
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Re: The Helix Nebula

Post by Graeme »

That's brilliant Ken! For a first go I would say you're a natural! I usually stretch the separate files and cut the black level then merge the channels. Seems to work well merging first too.

Have you mapped the Oiii to green in the centre there?

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Graeme

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Re: The Helix Nebula

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Graeme wrote:
14 Nov 2020, 17:26
...Have you mapped the Oiii to green in the centre there? ...
Umm, Can't remember :laugh: I thought opened each file, in turn, as they were listed in Explorer, which would have given me:
Ha --> red
Nii --> green
Oiii --> blue
but I was messing around so much anything is possible.

\Ken

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Re: The Helix Nebula

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It seems what I thought I did was not what I did. This version is definitely:
Ha -->Red
Nii -->Green
Oiii -->Blue
and tweaked so I can deliver that immortal line, "Here's looking at you kid"

Ken
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Re: The Helix Nebula

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One Ring To Bind Them All...
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Re: The Helix Nebula

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Yeah, that too :laugh:

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Graeme
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Re: The Helix Nebula

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Just out of interest this is what the three files look like in grey scale:

https://theskysearchers.com/viewtopic.p ... ii#p101239

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Graeme