Putting M51 to bed at last............for a nap

[Rodd]

I have been working on this image for years. I just could not take it beyond a certain point, and I have never been satisfied.  This is it....its close to what the data can support I think.  To be honest, it should have probably been binned 2x2 in software.  But Now its too late--when I bin the processed image definite loss of sharpness can be seen.  I would have to go back to the start and I just can't do it...Maybe in a few weeks.  At that time my goal will be to bin the data before processing, and to do a better job of adding the Ha--a few Ha spot are really strong and most are pretty week.  I think the Ha could be more evenly distributed and more pervasive.  I also think it might be too bright overall.  I have toned it down several times as I processed.  This the best balance I could achieve without losing all of the faint outer extensions, which are there, but noise levels in the background and faint signal levels of the extensions make it impossible to retain them while establishing a respectable background.   I am strongly considering adding some C11Edge data to the image in the next few weeks.  We'll see.  Not quite done after all, I guess.  But I want to enjoy this one for a while before I send it packing.  

TOA 130 native, ASI 1600, about 24.5 hours of data: 5 lum; 10 RGB; and 9.5 Ha.

 

 

[almcl]

The detail in the core is just fabulous, Rodd and the strong star forming regions, emphasised by the Ha, really pop.

Wonderful image as is.   

[Rodd]

26 minutes ago, almcl said:

The detail in the core is just fabulous, Rodd and the strong star forming regions, emphasised by the Ha, really pop.

Wonderful image as is.   

Thanks Almcl.  Much appreciated

[Rodd]

Here is a crop for easier viewing at a fitting scale

 

Edited January 23, 2022 by Rodd

[Adam1234]

I think that's incredible

[Rodd]

1 hour ago, Adam1234 said:

I think that's incredible

Thanks Adam

[Xiga]

Incredible amount of detail in the core you've captured there Rodd. Amazing what can be achieved with a 5" frac! 

[Kimboman]

Amazing and the background galaxies you must be well pleased thanks for sharing

[Rodd]

1 hour ago, Kimboman said:

Amazing and the background galaxies you must be well pleased thanks for sharing

Thanks kimboman. The background is the weak link

[Rodd]

2 hours ago, Xiga said:

Incredible amount of detail in the core you've captured there Rodd. Amazing what can be achieved with a 5" frac! 

Thanks Xiga.  When the sky is good it’s amazing 

[Catanonia]

Really nice and some didication to subs taken

What I like about this is that it is not over processed to death and you even got the faint wisp tail of the smaller galaxy

Nice framing too, getting a few smaller fuzzies in there.

[Rodd]

6 minutes ago, Catanonia said:

Really nice and some didication to subs taken

What I like about this is that it is not over processed to death and you even got the faint wisp tail of the smaller galaxy

Nice framing too, getting a few smaller fuzzies in there.

Thanks Catatonia.  that's my biggest pitfall....over processing.  It is so easy to go too far.  Someone I greatly admire once said to leave 10% of the image on the table (He might have said in the screen).  Now that I hink about it, I totally botched the quote, but the meaning remains clear.   Process  90% as much as you want to.  Leave a little for the imagination.  That way you wont go too far and will probably come to realize that you are closer to teh line than 90%.

[ollypenrice]

I wouldn't hesitate to crop it, Rodd, and bring it in closer as you did later. It holds up really well.

I do wonder if it's not a tiny bit black clipped? The sky is dark and smooth and the faint nebulosity looks slightly clipped on the upper side of the galaxy but this is only based on what we're seeing here.

The coloour is gorgeous, deep, rich and varied from blue to red.

Olly

[Rodd]

7 minutes ago, ollypenrice said:

I wouldn't hesitate to crop it, Rodd, and bring it in closer as you did later. It holds up really well.

I do wonder if it's not a tiny bit black clipped? The sky is dark and smooth and the faint nebulosity looks slightly clipped on the upper side of the galaxy but this is only based on what we're seeing here.

The coloour is gorgeous, deep, rich and varied from blue to red.

Olly

Thanks Olly--Playing around with the last crop.  I think the middle one is about the right size for this data.  I wouldn't be surprised if its clipped a bit.  I really don't have much choice with my sky (so I tell myself).  Background space with no nebulosity is always rather speckled and uneven for me, expecially at full scale.  I have complained about this since day one.  I have always thought it was LP.  It happens with all scopes and at all scales so I don't think its the instruments.  There is a Pixel Math formula for bringing the background to a consistant level.  But its very difficult to use without creating ungainly boundaries between the galaxy and background.   It tends to give a plasticy look somehow.  The faint extension were present to their fullest--like you see them on deep images.  But thy were very noisy.   I couldn't keep them and render a halfway decent background.   Its hard to shoot my way out of it (collect so much data that the background looks like yours).  I am at over 24 hours and there is a long way yet to go.  

[Hals]

Simply superb. The detail is excellent.

[Rodd]

8 minutes ago, Hals said:

Simply superb. The detail is excellent.

Thanks for looking Hal’s

[ollypenrice]

11 hours ago, Rodd said:

Thanks Olly--Playing around with the last crop.  I think the middle one is about the right size for this data.  I wouldn't be surprised if its clipped a bit.  I really don't have much choice with my sky (so I tell myself).  Background space with no nebulosity is always rather speckled and uneven for me, expecially at full scale.  I have complained about this since day one.  I have always thought it was LP.  It happens with all scopes and at all scales so I don't think its the instruments.  There is a Pixel Math formula for bringing the background to a consistant level.  But its very difficult to use without creating ungainly boundaries between the galaxy and background.   It tends to give a plasticy look somehow.  The faint extension were present to their fullest--like you see them on deep images.  But thy were very noisy.   I couldn't keep them and render a halfway decent background.   Its hard to shoot my way out of it (collect so much data that the background looks like yours).  I am at over 24 hours and there is a long way yet to go.  

Yes, you describe the problem very precisely here. Whether or not the technique could help in your case I don't know, but one way I like to reduce noise in the background sky is to do so using Curves. The idea is to lift the darkest background pixels to values very similar (but not identical to) those of the brightest background pixels. So I just pin the curve at and above the brightest pixels and lift it below that point. This compresses the range of background brightnesses, reducing noise but, critically, doing so without any of the pixel to pixel communication which causes the oily, noise-reduced look.  I'd be inclined to try this shortly before the final, hard stretch so this stretch could be done with a less varied background sky.

Once I have the background sky at the level I want and with the look I want, I now do the reverse of what I did in Curves earlier: pin at and below the background level and stretch only above it. This is great for dragging up the faintest nebulosity from out of the background.

Olly

[gorann]

An outstanding image Rodd! Love the details.

[Rodd]

2 hours ago, gorann said:

An outstanding image Rodd! Love the details.

Thanks Goran (ahhh....I just figured out the origin of me spellimng your name wrong.  I looked at you signature just now and said "You spelled your own name wrong!"  Then it dawned on me that the second n is the first letter of your last name. 

[Rodd]

5 hours ago, ollypenrice said:

Yes, you describe the problem very precisely here. Whether or not the technique could help in your case I don't know, but one way I like to reduce noise in the background sky is to do so using Curves. The idea is to lift the darkest background pixels to values very similar (but not identical to) those of the brightest background pixels. So I just pin the curve at and above the brightest pixels and lift it below that point. This compresses the range of background brightnesses, reducing noise but, critically, doing so without any of the pixel to pixel communication which causes the oily, noise-reduced look.  I'd be inclined to try this shortly before the final, hard stretch so this stretch could be done with a less varied background sky.

Once I have the background sky at the level I want and with the look I want, I now do the reverse of what I did in Curves earlier: pin at and below the background level and stretch only above it. This is great for dragging up the faintest nebulosity from out of the background.

Olly

Thanks, Olly.  I think that is pretty much what the Pixel Math formula does in a rough sort of way.  Equalizes the pixels so they can be adjusted together.  I am sure that manually one has much more control.  Your use of the phrase "pinned the curve" has always given me a buit of trouble.  Have you ever used PIs "curves"?  I wonder if the PS and PI curve tools are similar.   Your description is perfect--its precisely what I am inclined to do.......if I new how to get the tool to do it!

[ollypenrice]

6 hours ago, Rodd said:

Thanks, Olly.  I think that is pretty much what the Pixel Math formula does in a rough sort of way.  Equalizes the pixels so they can be adjusted together.  I am sure that manually one has much more control.  Your use of the phrase "pinned the curve" has always given me a buit of trouble.  Have you ever used PIs "curves"?  I wonder if the PS and PI curve tools are similar.   Your description is perfect--its precisely what I am inclined to do.......if I new how to get the tool to do it!

I've never used Curves in PI, Rodd. In Ps you can just place the cursor on a part of the image, Alt Click and that brightness point appears on the curve and will pin it if not touched. (Or you can raise or lower it, as you wish.)

Olly

[Rodd]

8 hours ago, ollypenrice said:

I've never used Curves in PI, Rodd. In Ps you can just place the cursor on a part of the image, Alt Click and that brightness point appears on the curve and will pin it if not touched. (Or you can raise or lower it, as you wish.)

Olly

Ahh….something similar in pi, but the points that appear on the curves toll are not permanent.  The dissappear when you unclick.  

[gorann]

19 hours ago, Rodd said:

Thanks Goran (ahhh....I just figured out the origin of me spellimng your name wrong.  I looked at you signature just now and said "You spelled your own name wrong!"  Then it dawned on me that the second n is the first letter of your last name. 

You are not alone but you finally got it Rodd! It is the  username I use for everything and it was once given to me about 26 years ago by the university I still work for. I assume they had other Gorans employed so the added the first letter of my last name. Sticking to it helps me to at least remember my username on different systems and platforms. Unfortunately, I also have to remember a plethora of passwords....

Edited January 27, 2022 by gorann

[gorann]

13 hours ago, ollypenrice said:

I've never used Curves in PI, Rodd. In Ps you can just place the cursor on a part of the image, Alt Click and that brightness point appears on the curve and will pin it if not touched. (Or you can raise or lower it, as you wish.)

Olly

I do the same as Olly when I stretch in PS. In fact almost every stretch I do has one or more pinned points on the curve so I can get the curve shape I need and seletively stretch the part of the histogram that needs stretching. No idea how one could live without them, but then I have never stretched an image in PI.

[Rodd]

4 hours ago, gorann said:

I also have to remember a plethora of passwords....

I know the security officianados would call me crazy, but I use the same password as much as possible.  I HATE passwords. It seems you need one for everything these days.