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Medusa Nebula (Abell 21) - a planetary nebula in Gemini


gnomus

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This is a large planetary nebula in Gemini.  It was originally thought to be a supernova remnant, but is now classiied as an old planetary nebula.  The data for this was captured over several nights at DSW on the Tak 106/QSI683 rig.

  • Luminance: 13x900" bin 1x1
  • Red: 14x900" bin 1x1
  • Green: 15x900" bin 1x1
  • Blue: 13x900" bin 1x1
  • Ha 5nm: 15x1800" bin 1x1

There are faint dusty substances over the field.  I'm still not sure how to pull these out without destroying the stars - so this represents a compromise position.

 

Abell_21_FINALx1920.thumb.jpg.6077c44c3d4c46fe2607dfbc313e656b.jpg

 

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Great image. As you wrote, there's more lurking in the background. But that's the fun in AP; trying to get the last photon out of the data.

Gerald Wechselberger has published a few video tutorials that may be relevant (PixInsight). But maybe that is old information.

http://www.werbeagentur.org/oldwexi/PixInsight/PixInsight.html

Thanks for sharing

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18 minutes ago, The Admiral said:

Did you say "dusty substances"? Takes me back to an old Peter Cook and Dudley Moore sketch :icon_biggrin:....

And here was me thinking I'd get away with it.  

Thanks for your comment about my photo.  Have you noticed how the nebula seems to follow you around the room?

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8 minutes ago, wimvb said:

Great image. As you wrote, there's more lurking in the background. But that's the fun in AP; trying to get the last photon out of the data.

Gerald Wechselberger has published a few video tutorials that may be relevant (PixInsight). But maybe that is old information.

http://www.werbeagentur.org/oldwexi/PixInsight/PixInsight.html

Thanks for sharing

Thanks Wim.  I'll take a look at it.  I'm aiming for 'naturalistic' though - whatever that means...

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34 minutes ago, gnomus said:

Thanks Wim.  I'll take a look at it.  I'm aiming for 'naturalistic' though - whatever that means...

= clouded, moonlit. Most of the time, but not for dsw data hopefully.

 

37 minutes ago, gnomus said:

And here was me thinking I'd get away with it.  

Thanks for your comment about my photo.  Have you noticed how the nebula seems to follow you around the room?

Now you've made me curious. I'm off to google.

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18 minutes ago, Barry-Wilson said:

Very nice Steve.  I too must add this to my list - thank you.

Now Pete & Dud . . . takes me back, so many quotes we cannot reproduce on the forum :evil5:

It might be good in the longer f/l scope - check ot out in the Framing and Mosac wizard.

I too am a fan of Pete and Dud, in both incarnations.  

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10 minutes ago, ollypenrice said:

Very classy image with everything in place. Background, stars, DS object. I don't care what Pete says, that's no Dud....

Olly

Ouch.  

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1 minute ago, Allinthehead said:

Very nice Steve. Would something like a screen mask invert in PS work on bringing out the feint stuff while protecting the stars?

Richard.

Thanks Richard.  I don't know is the answer.  I may give it a go.

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1 minute ago, ollypenrice said:

I don't think every image has to be a stunt. This makes a harmonious, convincing and natural whole. Sure, play around in search of the faintest stuff but don't feel obliged to torture your data.

Says the tutor of the headbanging curve. :icon_biggrin:

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Looking at the image on my computer, and not my mobile phone, I agree with Olly. There is some signal lurking in the background, especially weak Ha (maybe ERE?) to the left of the PN. But I think that in this case I would leave that to the imagination of the viewer, and not stretch the image further to squeeze out the last photon. There is a risk that noise will take over and that noise reduction will ruin the naturalistic effect of the image.

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Lovely shot - very natural looking, lovely colours, and agree that it doesn't look pushed by trying to drag the background stuff out - the subtle texturing works really well with the framing. 

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