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Old 18-06-2013, 01:50 PM
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Shiraz (Ray)
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M83

Hi

Two LRGB versions - the first one is native scale and with muted colour - tried to match "science" images on the web. The other is higher contrast and with more saturation, but it had to be reduced to 80% scale to keep chroma noise and artefacts from being too annoying. The hotter version shows the star formation regions quite well - maybe will try to add some Ha to the full scale version in future to enhance the new star regions.

Mount tracking noise messed up the brightest stars and I did not take any care over them - concentrated only on the galaxy. None of the available software could handle the heavily polluted colour data (particularly the red), so needed to manually set gain and offset in each channel after stacking to get any sensible results. Roll on clearer skies .

thanks for looking. Appreciate any feedback - been messing around with this data so much I can't see the woods for the trees anymore. Regards Ray

200f4 Newtonian with RCC1
SX H694
EQ6 with 50mm guidescope
LRGB 47:60:42:52
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Last edited by Shiraz; 18-06-2013 at 02:51 PM.
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  #2  
Old 18-06-2013, 03:02 PM
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marco (Marco Lorenzi)
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Beautiful Ray! I like them both, honestly the first version less saturated is as good as it can be on this target, so I would keep that one
Clear skies
Marco
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  #3  
Old 18-06-2013, 03:07 PM
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Lovely image, Ray. The first one appeals to me more. Great work!
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Old 18-06-2013, 03:32 PM
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Most excellent images and processing. I can see advantages in both types of processing.
Allan
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  #5  
Old 18-06-2013, 04:14 PM
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Both great but my preference is #1 too, Ray!
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  #6  
Old 18-06-2013, 04:19 PM
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I like the 2nd one. Its sensational.

Greg.
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  #7  
Old 18-06-2013, 04:35 PM
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Excellent Ray! For me the second one has more grab, looks great mate!

Hmmm? I will be putting the H694 on the AG12 soon

Mike
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  #8  
Old 18-06-2013, 04:50 PM
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tilbrook@rbe.ne (Justin Tilbrook)
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Like the detail and colour saturation in your first image Ray.

Your stars look like mine, I use a bintel 200mm f/4 reflector. I have tried various fixes, new coma corrector, fixing flexure and always check collimation.
But the always come out the same.
You mention mount tracking noise, what is this?
Would appreciate if you could fill me in on this.

Cheers,

Justin.
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  #9  
Old 18-06-2013, 04:55 PM
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asimov (John)
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Great work Ray. I love the second one best
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Old 18-06-2013, 05:28 PM
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Great work Ray,
That is very sharp & clear.
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  #11  
Old 18-06-2013, 06:37 PM
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Quote:
Originally Posted by marco View Post
Beautiful Ray! I like them both, honestly the first version less saturated is as good as it can be on this target, so I would keep that one
Clear skies
Marco
thanks very much for the helpful feedback Marco.

Quote:
Originally Posted by Larryp View Post
Lovely image, Ray. The first one appeals to me more. Great work!
Hi Laurie - thanks

Quote:
Originally Posted by allan gould View Post
Most excellent images and processing. I can see advantages in both types of processing.
Allan
Thanks Allan. I also am a bit unsure which approach is best - thanks for your comments

Quote:
Originally Posted by RickS View Post
Both great but my preference is #1 too, Ray!
thanks for the feedback Rick

Quote:
Originally Posted by gregbradley View Post
I like the 2nd one. Its sensational.

Greg.
hi Greg. very kind comment.

Quote:
Originally Posted by strongmanmike View Post
Excellent Ray! For me the second one has more grab, looks great mate!

Hmmm? I will be putting the H694 on the AG12 soon

Mike
Hi Mike. thanks for the comments. Looking forward to you getting the 694 going in your new wind free environment - spare a thought for us plebs with an EQ6 swaying in the breeze .

Quote:
Originally Posted by tilbrook@rbe.ne View Post
Like the detail and colour saturation in your first image Ray.

Your stars look like mine, I use a bintel 200mm f/4 reflector. I have tried various fixes, new coma corrector, fixing flexure and always check collimation.
But the always come out the same.
You mention mount tracking noise, what is this?
Would appreciate if you could fill me in on this.

Cheers,

Justin.
Hi Justin. I am not sure I am an expert on this, since I have been battling with this scope for years. However, I think that the current distortion is due to the mount producing very rapid tracking excursions that produce fleeting illumination outside of the main stellar spots. For dim stars, the excursions are too dim to see. For very bright stars, the excursions are smaller than the blobby stars so they do not cause distortion. for Intermediate brightness, the excursions are just bright enough to be visible, which leads to stars that vary in appearance with brightness. That's the theory anyway and my next job is to do some tests to see if it makes sense. test 1 will be to image some bright stars at very short exposures to see if the effect goes away.

I also found that diffraction patterns from bits and pieces of the OTA could be strange if the entering light column was not properly centered. You can use the reverse LED projector to test this.

Quote:
Originally Posted by asimov View Post
Great work Ray. I love the second one best
Hi Asi! thanks for the feedback

Quote:
Originally Posted by alpal View Post
Great work Ray,
That is very sharp & clear.
Thanks Allan. I was trying to optimise the resolution, so appreciate your comment.

regards ray

Last edited by Shiraz; 18-06-2013 at 07:18 PM.
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  #12  
Old 18-06-2013, 06:54 PM
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Fantastic scale Ray, nicely resolved. love the colours.
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  #13  
Old 18-06-2013, 08:41 PM
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marc4darkskies (Marcus)
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Apart from your minor guiding problems, that's a very good image Ray! Although I do tend to like more saturated colours I reckon the first one is best. Some great detail in there!! You could always blend the two. In Photoshop you'd blur the saturated version slightly and overlay it as a colour layer on top of the first and set opacity to taste to get the best of both worlds!

Cheers, Marcus
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Old 18-06-2013, 09:12 PM
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Really nice image there Nice resolution! I like the first one.
Erik
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Old 19-06-2013, 07:48 AM
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Hi Ray,

Love your images, but I do prefer #1 with a more muted colour approach. Your data sure looks "smooth!" Would you mind sharing how long your subs were and total times in LRGB? I'm working on this target too, but seem to be getting nowhere "fast" with lousy weather and getting used to new gear (ONAG + barlow on my TEC). I'm having the most trouble with RGB. Usually I try not to bin 2x2 because I don't like what it does to my smooth background in luminance (1x1). Probably I just need a lot more time in RGB to get a better result.

Anyway, I digress. I think your image is what I'm aspiring for! Congrats!
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Old 19-06-2013, 09:52 AM
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Quote:
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Would you mind sharing how long your subs were and total times in LRGB?
Its above the image Peter, LRGB 47:60:42:52

Thats a cracker of an image Ray.

Josh
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  #17  
Old 19-06-2013, 01:49 PM
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Nice work Ray. Just to be difficult, I prefer the colour of the galaxy in the first pic but the background of the second pic! (It's less hazy, but I realise that that may in fact be how it is.)

Chris
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  #18  
Old 19-06-2013, 03:33 PM
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Quote:
Originally Posted by Astroman View Post
Fantastic scale Ray, nicely resolved. love the colours.
Hi Andrew - Thanks

Quote:
Originally Posted by marc4darkskies View Post
Apart from your minor guiding problems, that's a very good image Ray! Although I do tend to like more saturated colours I reckon the first one is best. Some great detail in there!! You could always blend the two. In Photoshop you'd blur the saturated version slightly and overlay it as a colour layer on top of the first and set opacity to taste to get the best of both worlds!

Cheers, Marcus
Thanks for the kind comment and helpful advice Marcus - will give it a try, although I do not currently have PS

Quote:
Originally Posted by E_ri_k View Post
Really nice image there Nice resolution! I like the first one.
Erik
thanks Erik

Quote:
Originally Posted by PRejto View Post
Hi Ray,

Love your images, but I do prefer #1 with a more muted colour approach. Your data sure looks "smooth!" Would you mind sharing how long your subs were and total times in LRGB? I'm working on this target too, but seem to be getting nowhere "fast" with lousy weather and getting used to new gear (ONAG + barlow on my TEC). I'm having the most trouble with RGB. Usually I try not to bin 2x2 because I don't like what it does to my smooth background in luminance (1x1). Probably I just need a lot more time in RGB to get a better result.

Anyway, I digress. I think your image is what I'm aspiring for! Congrats!
Thanks for the comments Peter. Subs were 1 minute for L and 2 minutes for the colours - total times were LRGB 47:60:42:52. I also had huge trouble with the RGB and ended up manually adjusting levels and gains so that the data was within the ranges that the auto adjust algorithms in neb and pixinsight expected - biggest problem was upper level haze and thin cloud that picked up every bit of stray light from nearby street lights and even from Adelaide at about 50k distant.
I thought that I might get away with 2x binning for the colour, but the features in M83 are small coloured features and the colour res had to be as good as the lum - hence needed a lot more time on colour than on lum. If you are using a 2x Barlow, expect to sit there for 4x as long as you would without it - looks like there is no substitute for time.

Quote:
Originally Posted by Joshua Bunn View Post
Its above the image Peter, LRGB 47:60:42:52

Thats a cracker of an image Ray.

Josh
Thanks Joshua

Quote:
Originally Posted by ChrisM View Post
Nice work Ray. Just to be difficult, I prefer the colour of the galaxy in the first pic but the background of the second pic! (It's less hazy, but I realise that that may in fact be how it is.)

Chris
The galaxy does not have an abrupt boundary, but slowly fades - the only way I could show that was by bumping up the background, since it seems to be difficult to see very dark transitions on the average lappy display. Thus the haziness of the background of the first image. Is this better?

Regards Ray
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  #19  
Old 19-06-2013, 04:17 PM
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Thanks Ray. They say that beauty is in the eye of the beholder, and I suspect that this is most appropriate for astro pics. Looks great!

Chris
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  #20  
Old 19-06-2013, 07:13 PM
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RobF (Rob)
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2nd one all the way! What an image - that really says something for your rig and the RCC, which not everyone seems to love. Top stuff.
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