M27 The Dumbbell Nebula in HOO

[cometcatcher]

M27 The Dumbbell Nebula in HOO narrowband. First time I've imaged this in NB so had no idea what to expect. I like it.

From Wiki "The Dumbbell Nebula (also known as Apple Core Nebula, Messier 27, M 27, or NGC 6853) is a planetary nebula in the constellation Vulpecula, at a distance of about 1227 light-years. This object was the first planetary nebula to be discovered by Charles Messier in 1764... Given its semi-minor axis radius of 1.01 ly, this implies that the kinematic age of the nebula is some 9,800 years."

GSO 10" F4 Newtonian, ZWO ASI 183mm Pro at -10C, SVbony 7nm Ha and OIII filters, Ha 155 minutes, OIII 209 minutes, Bin2, HEQ5 Pro.

Full field at Astrobin ---> https://astrob.in/cn8b4m/0/

[Placidus]

Well done, Kevin. The faint outer extensions have come up beautifully, especially the OIII which is difficult.

We wonder if you might have over-smoothed the image to reduce noise in the faint outer extensions, and thereby lost bright detail in the core.

One way to avoid that is to use wavelet noise reduction, which will get rid of a lot of noise in the faint background but won't touch your brights.

Another possibility is that it was at low altitude and the seeing was very bad. The stars do look a bit blurry. Nothing you can do about that, and it doesn't detract from your magnificent achievement with the outer envelope.

Best,
MnT

[strongmanmike]

Yeah, other than the kinda soft look, the depth and colour is excellent, I love the fan like extensions on deep images of this baby, excellent :thumbsup:

Mike

[cometcatcher]

Thanks M&T and Mike.

Very light noise reduction was used. I notice the soft core also compared to RGB. Maybe that's just the way HOO is, especially with OIII as that is dominant in this image. I get much sharper cores with RGB on my SCT. Plus this 10" F4 is a right pain to focus.

[Andy01]

Notwithstanding the tech comments already made, that's a wonderful colour palette Kevin, looks great! :D

[cometcatcher]

Thanks Andy.

[codemonkey]

Nice one Kevin! I can't see any signs of over-zealous noise reduction, doesn't have that blotchy look.

[rustigsmed]

nice Kevin,

it is one i'd love to image but too far north - thanks for sharing - great colour and depth!

cheers

russ

[Atmos]

Very nice Kevin, not an easy target for us southerners!
Is the green channel a mix of Ha & OIII? Curious about the green core.

Even with the noise reduction it doesn’t look too blotchy, just smooth and not overly artificial.

[Paul Haese]

I like the palette Kevin, normally we see this object with the traditional red blue combination but this also works well. The outer extensions are well defined and processed. I think the soft look might be coming from the apparent elongation of the stars in a diagonal direction. Or could this be tilt in your Newtonian? Holding the camera square to the secondary can be problematic. The RGB problem you mention might come from focus and perhaps the need for offsets. I have found with both my Newtonians I have to use offsets in all filters to manage focus and this is with Astrodon filters.

[cometcatcher]

Thanks Lee. Noise reduction from memory was 3/10, so fairly light.



Thanks Russ. Ah you miss some of the good stuff! I do need some more tree pruning yet though lol.



Thanks Colin. Yes there is some Ha and OIII in the green channel, I think from my faulty memory. It started out as HOO but I'm not sure how it ended up as I took a few days to process it a little at a time. Sometimes I just have to step away for a while to regain perspective.




Thanks Paul. There are a few suspects what could make the elongated stars. They are not always there, so perhaps the scope loses collimation and / or focuser tilts at certain angles. Being a soft metal tube, that is on the cards. Andrew and Mike have similar scopes and they have reinforced around the focuser with good results. I might have to do the same.