Ghost Nebula (SH2-136)

[alan4908]

My first attempt at the Ghost Nebula.  This is an LRGB image taken with my Esprit 150 and represents about 17 hours integration time.

 

 

Alan

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For those interested, here's a summary of my acquisition and processing challenges:

I started gathering data with my standard 600s sub exposure duration.  However, having accumulated quite a few of these, I decided this wouldn't give me enough detail, so I increased this to 1200s subs in the Lum which made a substantial improvement to the image quality. I also discovered that the nebula contains some bright stars which are so intense that they pushed my camera into the non-linear region for the 600s and 1200s lum subs. So, to overcome this, I decided to take some 60s Lum subs and then created a high dynamic range Lum image within CCDstack by combining the 60s, 600s and 1200s stacks and rejecting all the pixels that where above my cameras non-linear threshold.  

On the processing front, I struggled with the background since it contains so much dust and numerous red/yellow stars.  I eventually decided to de-emphasize some of the dust and red stars since too me they proved distracting to the main subject, namely the Ghouls in the nebula. 

L: 60s x 41, 24 x 60s, 12 x 1200s, R: 18 x 600s, G: 13 x 600s, B: 21 x 600s. DARKS: 30, FLATS:40, BIAS: 100 all at -20C. 

[MarsG76]

A W E S O M E ! ! ! ! ! ! .. Such a pity I cant see it from my latitude.

[swag72]

Super!!! You've done really well on a tricky target..... Hats off to you   

[smr]

Amazing image.

[JimothyC]

Wow that's fantastic. Very ghostly. I've not seen an image of the Ghost Nebula before, it's quite a unique looking DSO. 

[celestron8g8]

Awesome captures ! Never seen them before , thanks for sharing ! 

[alan4908]

18 hours ago, MarsG76 said:

A W E S O M E ! ! ! ! ! ! .. Such a pity I cant see it from my latitude.

Glad you liked it !

18 hours ago, swag72 said:

Super!!! You've done really well on a tricky target..... Hats off to you   

Thanks Sara.   - I agree it is tricky, albeit a highly rewarding target. I particularly like the faint blue reflection nebulosity.

17 hours ago, celestron8g8 said:

Awesome captures ! Never seen them before , thanks for sharing ! 

Thanks very much 

[MarsG76]

38 minutes ago, alan4908 said:

Glad you liked it !

Whats not to like in this masterpiece?

[carastro]

A great image, I would have brightened it up a bit more as you can see another ghost at the top of the image.

Carole 

[Shibby]

??️‍♂️

Awesome! Fantastic image of a great nebula.

I hope you'll forgive a bit of nit-picking, but there's a few dark halos remaining around the stars in front of the nebula. The image is otherwise perfect!

[alan4908]

4 hours ago, carastro said:

A great image, I would have brightened it up a bit more as you can see another ghost at the top of the image.

Thanks for the comment Carole.

I did actually brighten up everything but decided that a "dark and moody" image worked better, particular since my main focus was on the Ghost's.

56 minutes ago, Shibby said:

Awesome! Fantastic image of a great nebula.

I hope you'll forgive a bit of nit-picking, but there's a few dark halos remaining around the stars in front of the nebula. The image is otherwise perfect!

Thanks Shibby - yes, please nit pick away - it is the only way I seem to improve.  I shall investigate the few dark halos.....

Alan

[alan4908]

5 hours ago, alan4908 said:

I shall investigate the few dark halos.....

Investigation over - they are caused as a result of blending a low DDP Luminescence stretch with a high DDP stretch, which I did in order to de-emphasis the stars. However, what I didn't take into account is that the background levels are slightly different, which gives a slight darkness around the stars within the brighter parts of the nebula.

Here's a quick PS fix to the problem achieved via the context aware healing brush combined with the Lighten blending mode.

Thanks again @Shibby for spotting this, I shall attempt not to make the same mistake again !

Alan

[Shibby]

Great job, that's better  I always have the same problem when using any sort of star layer, which is maybe why I noticed!

[wornish]

Fantastic image.  Not seen this one before.

[alan4908]

20 hours ago, Shibby said:

Great job, that's better  I always have the same problem when using any sort of star layer, which is maybe why I noticed!

Yes - I'm not very good at processing star fields at are embedded within nebulosity, although I am attempting to improve via practice 

20 hours ago, wornish said:

Fantastic image.  Not seen this one before.

Thanks Dave ! 

[ollypenrice]

With the dark halo fix you have an absolute winner, one of the best Ghosts I've ever seen. In fact I've just scrolled back up for a third look and - damn - that's good!

Hats off.

Olly

[alan4908]

7 hours ago, ollypenrice said:

With the dark halo fix you have an absolute winner, one of the best Ghosts I've ever seen. In fact I've just scrolled back up for a third look and - damn - that's good!

Hats off.

Olly

Thanks Olly 

I definitely need more practice with stars embedded with nebulosity.... I shall try going down the starlessless + starfield approach to see if that produces better results.

[ollypenrice]

25 minutes ago, alan4908 said:

Thanks Olly 

I definitely need more practice with stars embedded with nebulosity.... I shall try going down the starlessless + starfield approach to see if that produces better results.

Everybody needs more expertise at this! It's the holy grail. If you want a real killer to practice on try IC342. Oh boy...

Olly

[jimao22]

Great image! Best Ghost I sever seen. Congrats!

[gorann]

Yes, that Ghost is really something else! After you removed the rings it is flawless. I am particularly excited to see that this was accomplished with an Esprit 150 since I recently bought one. You have just shown that the sky is the limit with that scope.

[alan4908]

16 hours ago, jimao22 said:

Great image! Best Ghost I sever seen. Congrats!

Thanks ! 

 

7 hours ago, gorann said:

Yes, that Ghost is really something else! After you removed the rings it is flawless. I am particularly excited to see that this was accomplished with an Esprit 150 since I recently bought one. You have just shown that the sky is the limit with that scope.

Thanks Gorann.

Yes, I'm very happy with the performance of the Esprit 150, it is quite an outstanding telescope for the price.  Good luck with your own image captures ! 

Alan

[Allinthehead]

Lovely image Alan.

[gorann]

1 hour ago, alan4908 said:

Thanks ! 

 

Thanks Gorann.

Yes, I'm very happy with the performance of the Esprit 150, it is quite an outstanding telescope for the price.  Good luck with your own image captures ! 

Alan

Could it be that it is not just outstanding for its price, but actually as good as a 6" scope can be. Or would any other 6" telescope be any better? The responses here suggest that none of us have ever seen a better Ghost...

[alan4908]

9 hours ago, Allinthehead said:

Lovely image Alan.

Thanks for the comment Richard. 

9 hours ago, gorann said:

Could it be that it is not just outstanding for its price, but actually as good as a 6" scope can be. Or would any other 6" telescope be any better? The responses here suggest that none of us have ever seen a better Ghost...

Hmm - well I personally, would not make that claim mainly due to the fact that I have never tested other 6" refactors in comparison to the Esprit 150. However, if you look at the price of (say) a TOA 150 compared to the Esprit 150 then the price/quality point is interesting. 

Alan 

[gorann]

4 hours ago, alan4908 said:

Thanks for the comment Richard. 

Hmm - well I personally, would not make that claim mainly due to the fact that I have never tested other 6" refactors in comparison to the Esprit 150. However, if you look at the price of (say) a TOA 150 compared to the Esprit 150 then the price/quality point is interesting. 

Alan 

And on SGL I see repeated claims that this Japanese brand has problems with QC nowadays while FLO says that it almost never have any QC issues with the Esprit line when Es Reid do their pre-dispatch optical bench test.