alan4908

M76, which is also known as the the Little Dumbbell, Cork or Butterfly Nebula is a planetary nebula about 4.5 light years across and approx 4000 light years distant. It was formed about 10,000 years ago when the central dying star lost a huge amount of matter.  The structure of the nebula has two inner lobes and two fainter outer ones.  High Ha emissions are present along with OIII emissions which create a the teal (blue/green) cast.

As for the title, the bright star reminded me of Sunrise on Earth, hence the name. 

(For the more literal among you, the bright star is HD10498 which has apparent magnitude of 6.6, so you'd probably be unable to see this with the naked eye.  It's about 27x the size of our Sun and is approx 900 light years distant). 

The LRGB image below represents over 15 hours integration time and was taken with my Esprit 150.

Alan

LIGHTS: L:36, R:20, G:16, B:20 x 600s, DARKS:30, FLATS:40, BIAS:100 all at -20C.

17 hours ago, gorann said:

Beautiful! I like it a lot for many reasons. I was aiming at the same target for the first light of my 14" Meade LX200R (ACF) about a week ago. Olly  @ollypenrice will like the comparison since he argues for the superiority of large refractors, and I can see that you have about the same level of resolution. So your Esprit 150 is obviously a great galaxy hunter (fortunately I am also an Esprit 150 owner). To the 14" SCT defence I could say that I only grabbed 5 hours and it seems to have picked up the faint stuff a bit better. But maybe you did not stretch the data as much as I did. The final 5-hour version of my image is at the end of this string:

 

Thanks for the comment gorann.

It is interesting to compare the image from my Esprit 150 with that of your 14" Meade LX200R.  Your image looks very nice by the way, particularly for only 5 hours integration time !

As you say, they do seem to give a similar level of detail - perhaps at one level that is not surprising since I'm at  0.7 arc seconds per pixel and you appear to be at 0.85.  From my particular site, I've previously concluded that there's likely to be little benefit from a higher resolution DSO imaging set up.

On the faint stuff - a possible explanation for less nebulosity in my image is that this  consists of two blended images: galaxies and a star field. I deliberately stretched the star field much less than the galaxies to obtain better star colours and much less star bloat.  Hopefully you cannot spot the join. 

Alan

1 hour ago, dave_galera said:

Beautiful image well captured

Thanks Dave. 

14 minutes ago, ollypenrice said:

Very nicely done indeed. Just a thought but for that very bright innermost little core have you considered using your RGB-only in the way that you'd use a set of short luminance subs just to stop that bit saturating?

Olly

Thanks Olly. No I hadn't considered that but it is a good idea to try, so thanks for the tip.

It is a very interesting object to process due to the high dynamic range of both the galaxy and the surrounding stars, some of which are quite bright. 

Alan

16 hours ago, StuartJPP said:

A cracking image, love these galaxy shots.

Thanks Stuart  

Alan

13 hours ago, kirkster501 said:

Very nice.  I'm liking it very much.  A new one on me this object.

Thanks for the comment. 

12 hours ago, tomato said:

Great result, the Deer Lick cluster is nicely framed also.

I’m trying to be patient while construction of my permanent observatory continues, but having the 150 stuck in it’s case now the dark nights are back is frustrating to say the least.

Thanks.

It must be very frustrating for you, still you should have a nice observatory to look forward to soon.

Alan

That is impressive. 

Alan

5 hours ago, Davey-T said:

Very nice Alan, been taking subs of it on and off on recent clear nights, hope mine comes out anywhere as good as your version.

Dave

Thanks Dave - it took me rather a long time to acquire this, which wasn't particularly helped by the UK weather...... Good luck on your own rendition !

1 hour ago, peter shah said:

A great shot with lovely colour and scale to it

Thanks Peter. 

The galaxy NGC7331 is located in Pegasus and is approximately 46 million light years distant. It's estimated to be be substantially larger than our own Milky Way with a transverse diameter of 140 000 light years.   Some background galaxies can also be seen in the image (below), which are estimated to be c300 million light years distant  Due to its high inclination of 77 degrees, part of the disc is blocked by dust lanes, although I was quite pleased with the amount of detail captured. 

The LRGB image represents 11.5 hours integration time and was taken with my Esprit 150.

Alan

LIGHTS: L: 16, R:17, G:17, B:19 x 600s. DARKS:30, FLATS:40, BIAS:100 all at -20C.

Very impressive Olly and nicely framed.

Alan

On 05/08/2019 at 08:58, maw lod qan said:

A amazing image. 

Thanks for posting it along with the information. It's like back to school here on the forum. Except I enjoy this learning.

Thanks. Yes, it's interesting what you can learn from this hobby. 

Alan

6 hours ago, Rodd said:

Nice colors--well done

Rodd

Thanks Rodd ! 

2 hours ago, ollypenrice said:

A tempting and famous five, nicely done. 👋 We're working on this at the moment, not too far from where Edouard Stephan discovered the objects from Marseille. (You wouldn't discover too much from there these days!) The distance to NGC7320, according to redshift, is about the same as to the nearby NGC7331 but Halton Arp didn't accept this and used it as an example to challenge the redshift as a reliable distance measurement. An intriguing controversy. Both your data and ours shows an arc of tidal extension from NGC7320 which is parallel with a similar arc from NGC7319. You have to say that Arp has a valid question if he he asks why there should be two parallel tidal extensions from galaxies at radically different distances from NGC7331, if that is the attractor.

Olly

Thanks for the comment Olly. 

Yes, you can definitely see what appears to be a tidal tail emanating from NGC7320. However, I found this article on the subject from c10 years ago (http://chandra.harvard.edu/blog/node/150) which suggests it is an optical illusion. It states: Radio observations prove that the tail is unrelated to NGC7320 and is actually connected to the X-ray mission and the two spiral galaxies on the right (NGC7318a/b). The radio lets us see cold neutral hydrogen gas in the tails and trace the southern tail even where it passes behind NGC7320; there is no sign of disturbance in the gas or a connection to NGC7320, and the hydrogen is at the redshift of the other galaxies.

Alan

Stephan's Quintet is located in the constellation of Pegasus and was discovered in 1876 by Edouard Stephan using a 80cm reflector. Originally, he perceived the close pair (NGC 7318 A/B) as a single galaxy, so originally it was perceived as a quartet.  One of the galaxies (NGC 7320) is actually much closer to Earth (45m light years) than the rest which are much further away (287m to 310m light years). 

I thought a good challenge to have a go at the object since a search revealed that their are relatively few amateur images, probably because it is so tiny. The resultant LRGB image represents just over 12hours integration and was taken with my Esprit 150. 

I've also captured a few other galaxies in the image below which Pixinsight has annotated.  The one near the top right wasn't picked up,  however, a quick search on the free program Aladin informs me it is 2MFGC 17021.

Alan

LIGHTS: L:30, R:13, G:11, B:19 x 600s; DARKS:30, FLATS:40: BIAS: 100

Annotated version

3 hours ago, ollypenrice said:

I've heard this described as the 'vaseline on the lens' look which creates a fairly large scale mottle while removing all grain. Compare that with the grey-ish outer shell of your nebula. While I dare say you've applied some NR to this it still has a fine surface grain which I feel keeps it natural looking. 

Hi Olly

Just to let you know that I've found the root cause - a little too strong application of Pixinsight's TGV Denoise. As I previously mentioned,  I can see the effect when I zoom in but in posted image I cannot, which is why I missed this whilst processing. 

Many thanks again for your critique, hopefully this will allow me to improve. 

Alan

1 hour ago, MarsG76 said:

Thats close.. very smooth.. perhaps the NR is a bit heavy but the detail is still there.

Thanks 

Alan

Olly

Many thanks for the explanation. I must admit that I cannot see an issue in the areas you've marked on the posted image. However, when I zoomed in on the TIFF I can definitely see what I would describe as a soft focus effect in parts of the image.  So if I zoom in on the fours corners and centre of the image I get this:

If you look at the stars, the top left is most soft focus with the centre being the most sharp.  Now that I can see this,  I shall now explore where this came from.  

Alan

1 hour ago, alan potts said:

A lovely image indeed, must have try for this one , and if half as good I will be happy.

Thanks Alan 

23 minutes ago, ollypenrice said:

I don't think the algorithm chosen is very important, it's how far it's applied and where. For me Photoshop is perfect for the job because you can use layers rather than masks and then easily and quickly select the parts to be noise reduced with the opacity slider there to decide on the extent. I would make a copy layer and apply very slightly excessive NR globally to the bottom layer. Then, on the top layer, I'd use the colour select tool to choose the noisiest parts and run a partially opaque eraser over the selection. I might then expand the selection, reduce the opacity of the eraser and apply it again. This way you can see what you're doing as you do it.

Olly

Many thanks for the tip Olly - I don't use the technique you describe but I shall give it a go.

One final thing, would you mind indicating which parts of the nebula you believe have excessive noise reduction. I compared my image with a Adam Block reference ( http://www.caelumobservatory.com/gallery/ic5146.shtml)  and I cannot see the issue. 

Alan

19 hours ago, ollypenrice said:

I like the nebula very much.  The little blue nebula is very reclusive but you have it!

I'm less keen on the noise reduction around the main nebula. Some was doubtless necessary but I always feel that, when you can see it, it's too much.

Thanks for the comment Olly. 

I'll  go back to my processing to see if I've overdone something on the noise reduction front. I have to say that I find noise reduction very challenging to get good results. Currently, I'm hoping between Pixinsight, PS and NeatImage.......

Alan

On 26/07/2019 at 12:29, glowingturnip said:

i like that a lot, the squirly bits at the front, in front of the bright starlight 

Thanks Stuart ! .....personally, I was a bit surprised to see the features of a Christmas Reindeer appear in the red nebulosity to the left of the very bright blue star in the center of the image 

Alan

For me, overall I  prefer the right image. However, I also prefer the Ha regions, the redness and the core detail in the left hand image. So, if you blend the two images together on a simple 50 50 basis you get this:

Alan

19 hours ago, glowingturnip said:

wow

Thanks Stuart 

Alan

Bryan

Before you add more data and since you have good data, you may want to try a different mapping of narrowband to RGB colours. 

Specifically, try Ha mapped to Red and OIII mapped to Blue. You then need to create a synthetic green, I suggest using Noels actions if you use PS. 

Alan

If you like your sleep and accurate focusing then I would suggest you consider a move to automated focusing.  Seeing is a particularly important consideration when attempting focus. 

I currently:

1. Use filter offsets between my range of RGB and narrowband filters. These are pre-calculated by ACP and are used whenever I change filter. All of these are made with respect to the lum filter.

2. Use the free version of FocusMax for my automated focusing with the exception is that I let ACP choose the focus star.  I've programmed ACP to select the focus star such that it is between 6 and 9 and it's near the zenith.  FocusMax then works out the exposure by taking several exposures, working out the incoming flux and ensuring that the focus star is non-saturated, sufficiently bright and is on the linear portion of my camera. The reason I choose a focus star near the zenith is to minimize the effects of seeing, which will lead to a greater uncertainty in your focus. 

3. Automatically refocus about every 2 hours to allow for changes to seeing/temperature etc. 

The interesting thing about FocusMax is that it attempts to work out best focus from data gathered at near focus, this is again to minimize the effects of seeing.

Alan

That is a very impressive Bubble Peter.  Excellent stars and good detail.

One thought....on the Ha 30min subs used for the detail you mentioned above that you decided to use the best 15 out of 128. I was curious to know if you'd tried using an alternative approach: use a much higher percentage of subs,  which would give you a slightly less detailed result but much improved signal to noise ratio.  This would enable you to apply a much stronger deconvolution which would assist in recovering the lost detail. 

Alan

49 minutes ago, kirkster501 said:

Think: If you are imaging a nebula, say, and subsequently discover that you have star trails, the nebula will be trailing as well.......  No amount of tinkering in deconvolution or sharpening is going to change that fact.  Past a certain point, the sub is useless and you are defeating your purpose of creating a nice picture by trying force dodgy subs into your final composite.

Well, I agree with two parts of your statement: 

1.  "If you are imaging a nebula, say, and subsequently discover that you have star trails, the nebula will be trailing as well".....which translates into my comment above that this will introduce a slight blur. 

2.   "Past a certain point, the sub is useless" - absolutely - subs which have very large star trails or very poor signal to noise I'd definitely exclude.

However......

What Vlaiv is suggesting is performing a convolution on the suspect subs to try to minimize this blur. In theory this should work, in Pixinsight (for example) you can set use a deconvolution option which allows you to set the angle of the blur and (hopefully) improve the result.  I personally tried this but found it quite difficult to get good results.

What I am suggesting is that it depends on what you want to achieve and on the type of subs in which the blur is occurring. Also remember that if you are constructing a LRGB image, it is quite common post processing practice to blur the RGB data before combining the data with the Lum to reduce colour noise. This is because most of the detail comes the Lum rather than RGB layer.  So, here, you are deliberately introducing a blur in order to produce a better looking image. So, if you have the data, all I am saying is that it only takes a few minutes of experimentation before you make the decision to throw away all the trialed subs. 

Alan