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Is Methuselah wearing a dusty shawl or is it just my old eyes?

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#1 CCDer

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Posted 12 August 2019 - 05:08 PM

Only after processing and posting the Methusulah nebula on Astrobin did I take longer looks at the data.

 

http://www.astrobin.com/full/420612/0/

 

After studying it awhile, to my eyes anyway, looks like the parts of the nebula I originally thought were blasted away are maybe only obscured by some of that dark dust between us and Cygnus. I originally did a Dark Structure Enhancement and reversed that because that didn't fit the picture in my mind. Now I'm thinking the opposite.


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#2 RunningMan

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Posted 12 August 2019 - 05:17 PM

Wow! That’s a cool image!

#3 Redbetter

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Posted 12 August 2019 - 05:54 PM

What wavelength is the bright section in the upper portion of the nebula mapped to?  This segment is  most of what is visible in the SDSS images, but is only present as a faint blue there.  I am wondering if this is primarily OIII, a mix with H-alpha and H-beta or if it is more of a reflection nebula.  I am wondering if I can get any hint of it visually in dark sky. 

 

MWP1 is somewhat misplotted in Wikisky...I had to locate it by eye in Wikisky well to the southwest.



#4 CCDer

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Posted 12 August 2019 - 06:05 PM

The pink is a mostly even mix of Ha and O3. I blended the Ha into the blue as well by .1 for an Hb component. The O3 was blended 50/50 into Blue and Green.

 

The more I look at this pic, the more it looks like the nebula is a mostly intact egg shape that's pushing away dust on it shock front in all directions. The odd sawtooth pattern on the bottom might just be the dust being pushed aside by the shock wave.


Edited by CCDer, 12 August 2019 - 06:05 PM.

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#5 Redbetter

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Posted 12 August 2019 - 06:44 PM

Overall color and structure are reminiscent of portions of an azure vase sponge and some more delicate varieties I have seen during various dives.  The nebula image itself is fantastic but I am not quite sure what to make of the background.

 

With respect to the surrounding star field, is the contrast boosted a little too much with the background?  The contours of the glow around the many individual stars in the field seem somewhat too rounded yet sharply defined relative to black.  Keep in mind, I am not an imager, so this is a question rather than an actual criticism.  I am trying to understand what is real and what might represent an artifact of the processing. 



#6 CCDer

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Posted 12 August 2019 - 07:09 PM

Yes, those holes in the background are the result of star removal and replacement with smaller stars. I used starnet++ for  the first time to remove stars and I think it's great. It does leave artifacts though. I could spend some more time using Photoshop's heal function. I eliminated almost all artifacts off the nebula area but with >9000 stars in the uncropped image (according the the PSF tool in PixInsight), it's a big job to get them all with this dense star field. 

 

Azure vase sponge sounds good! Maybe even those ancient containers for hauling wine in (without the handles).

 

The deal is there are very few images of this planetary and I think they all don't show dust, just gaps in the nebula that make you think the nebula explosion was at least partially asymmetric. But from what I see in this image, it looks completely symmetric and mostly intact (on one side anyway). Its just partially obscured in dust which is maybe something new. Or... maybe not, if I'm not seeing straight. 



#7 CCDer

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Posted 12 August 2019 - 11:22 PM

So I did PI's dark structure enhancement and a re-crop and the "dark dust shawl" is very convincing, at least for me.

 

http://www.astrobin.com/420612/B/



#8 Jim Thommes

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Posted 13 August 2019 - 05:49 PM

Mark,

First off, this is a very impressive image - nice work.

 

I am divided regarding your hypothesis of foreground obscuration by dust. Your image hints at it (as do some other images). But it is hard to come away with an abiding conviction from these visual spectrum images. I took a quick look at IR data from WISE, but it doesn't show any strong returns around MWP1. Perhaps it remains a mystery for now?



#9 CCDer

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Posted 13 August 2019 - 06:08 PM

Jim,

 

Thanks for checking. The artifacts I think I'm seeing would be totally attributed to the Ha used in the image. Do you know if IR data completely correlates to Ha emissions and dust?  

 

Edit: Actually the darkest parts of the image would be areas of no Ha/O3 emissions next to areas with Ha/O3 emissions.


Edited by CCDer, 13 August 2019 - 06:19 PM.


#10 lucam

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Posted 13 August 2019 - 06:37 PM

Mark, that's such a cool image! I love the colors. Unusual and and very pleasing.



#11 CCDer

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Posted 13 August 2019 - 06:56 PM

So I'm contemplating all the dark structures I've been seeing in my images and wondering just what that "darkness" means. The darkest areas of those structures always correspond to a complete lack of stars. Generally, introducing Ha into the Lum increases areas of darkness. I've always assumed the darkness corresponds to some agent, (i.e. dust) completely blocking light. The darkest areas in this image are directly adjacent to the nebula and seem to correspond with an absence of stars. Now these areas have been enhanced with PI's Dark Structure utility but they're clearly present before using this utility. So how do we read the data? I'm confused.



#12 Redbetter

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Posted 29 August 2019 - 07:13 PM

I observed this nebula in dark sky (21.70 MPSAS) two nights ago with the 20".  While I was only able to see the brighter section it was not too difficult to find using 31T5 Nagler and DGM NPB filter.  I then switched to OIII which increased the contrast.  It is still only a faint haze, but it is there visually.  I need to revisit with a more detailed chart to ID the central star (which is not in the nebula section visible by eye) and perhaps sketch what part of the nebula is seen.

 

Thanks for the heads up on this one. 




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