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Hi everyone,

This is the 2nd ever DSO I have captured (the first being Pleaides). I have very limited experience processing images after stacking. I have attached some of my efforts to draw detail out of M51.

There is only around 30mins of data in the TIF file (30x60sec @ ISO800, Skywatcher 200DPS), 10 darks and 10 bias. This is all I could capture before the clouds rolled in. I have tried following some youtube tutorials but am struggling to get rid of the grey-ish tinge to the image and reduce the noise. There also seems to be a dark horizontal band across the image which I think might be a stacking artifact ? I am using Photoshop and have mainly been adjusting levels and curves but not quite sure where to go next.

If anyone could give some advice on processing M51, what processing steps they normally take etc.....or even have a quick go at processing it that would be amazing.

Thanks in advance

Autosave001.tif

whirlpool1.jpg

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On 18/04/2018 at 22:24, f33n3y said:

or even have a quick go at processing

Hi!

Well I have had a quick go at processing your image. I've used PixInsight and Photoshop. I cropped the outer edges a little before applying DynamicBackgroundExtraction twice - once in subtraction and once in division. I then created a mask so I could try to reduce the noise in the background using MultiLayerTransform process. I then cloned the image and performed a HistogramTransform stretch on one of them and an Arcsinhstretch on the other. I then saved them into Photoshop and used a layers to pull the colour from the arcsinh stretch into the histogram stretch image. I followed that up with some very careful use of the dodge and sponge tool and a final noise smoothing using Dfine.

A lot more data would help pull out the details in M51 and some flats would help reduce the background gradients. Have to say you've done better than I ever did with a dslr. To me the image looks very well focussed and I like the framing - personally I like to see these targets surrounded by the vastness of space and not totally filling the frame.

Hope this is of interest.

Autosave001_combine.thumb.jpg.1ae7ec09af595883d31d4e9db8f5a2c7.jpg

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9 hours ago, Adreneline said:

Hope this is of interest.

Autosave001_combine.thumb.jpg.1ae7ec09af595883d31d4e9db8f5a2c7.jpg

Wow, thank you so much Adreneline! This was my first ever galaxy shot and for that reason I think it will always be my favourite now!

I'll need to take a note of those steps and try recreate for practice. Glad that my focussing is okay as i'm still just focussing by zooming in on a star (Arcturus on that night). Hopefully get a bahtinov sorted soon.

 

 

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11 minutes ago, f33n3y said:

I'll need to take a note of those steps and try recreate for practice.

If you have not done so already you might find it helful/useful to buy a copy of 'Dark Art or Magic Bullet?' by Steve Richards @steppenwolf; the book provides valuable advice and guidance on using Photoshop to process astro-images.

20 minutes ago, f33n3y said:

i'm still just focussing by zooming in on a star

You don't say which camera you are using. I use a Canon 70D which I drive with BackYardEoS. BYEoS provides a focussing assistant which I find works really well although I know that others on this forum prefer to use the Live View feature on the camera; there is also a version of BYEoS for Nikon cameras. APT also provides focussing aids including a software implemented Bahtinov Mask. I am pretty sure both BYEoS and APT are available as fully functional trial software

Good luck!

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wwhirlpool1.jpg.498d964bcdf2af8280a03e14ff83c51a.thumb.jpg.6fbcc747345b04568882c358dd8dfe39.jpgI downloaded your posted image .jpeg not the tiff. Opened in GIMP paint program and duplicated your image then altered the top layers properties from "normal" to "multiply" (sometimes "overlay" or other layer types work)...I then merged visible layers and repeated the above steps. I don't do astro photography this is my amateur method:thumbright:

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On 18/04/2018 at 22:24, f33n3y said:

If anyone could give some advice on processing M51, what processing steps they normally take etc.....or even have a quick go at processing it that would be amazing.

Attached below is a quick process in PixInsight and Photoshop, I have pulled the galaxy as hard as possible, probably a little too far....

Steps taken in PixInsight were:

Dynamic Background Extraction, correction by division.

Background Neutralisation.

Colour Calibration.

TGVDenoise.

Deconvolution.

Apply Inverted Range Mask.

HDR Multiscale Transform.

ArcSinH Stretch.

Remove Range Mask.

Masked Stretch.

Apply Inverted Star Mask.

Colour Saturation, stars.

Remove Inverted Star Mask.

Apply Inverted Range Mask.

Colour Saturation, galaxy.

Remove Inverted Range Mask.

Histogram Transformation.

Save as Jpg.

Move to Photoshop for final steps:

Crop.

Reduce colour saturation in red channel.

Reduce Exposure and Gamma across all channels.

Save as Jpg.

____________................._________________

There are not too many comments to add. Flats will help with your post processing, leaving you less to try and correct for afterwards, especially since you are using Photoshop where correcting for vignetting is quite time consuming.

For the number of exposures you took there is a surprising amount of useable data captured but there is only so far you can go before the inherent noise in the data becomes apparent, for this target with your equipment three hours of data would be a good starting point and that would allow you to stretch the data much harder while leaving the noise behind.

When you comment that you are struggling to get rid of the greyish tinge to the image, for the background that is a good position to be in, the trick is to stretch the galaxy while trying to keep the background neutral. In Photoshop you use layers for that and selective reveal, in PixInsight we use masks.

I like the way that you have kept the background noise under control in your image and this has allowed you to pull the galaxy above background and just give a hint at the colour in the galaxy. Focus is good for the galaxy, there is some coma around the image edges. If you are not using a coma corrector this is normal, if you are using a coma corrector check that the spacing to the camera sensor is correct and that there is no tilt in the optical path.

The image has some horizontal banding, typical of some Canon Cameras. If you intend to stay with Photoshop and are using the full photoshop program then have a look at adding a set of action plug-ins specifically developed for astrophotography such as Noel Carboni's Astronomy Tools Action Set, or Annies Astro Actions. Noels Tools contains a nice horizontal and vertical de-banding action and several other useful tools such as light pollution gradient removal, star colour boost and background noise reduction amongst others.

http://www.prodigitalsoftware.com/Astronomy_Tools_For_Full_Version.html

http://www.eprisephoto.com/astro-actions

Action set plug-ins don't offer anything you can't do yourself, it just speeds up the process, and they won't run on many of the versions of Photoshop essentials, you have to have a full version of Photoshop to install and run actions so if you intend to buy them make sure your version of Photoshop is compatible. Once you understand how actions work you can easily make your own though I have to confess I still find still Photoshop a bit of a dark art, despite using it for many years. As an engineer I prefer PixInsight because I am more comfortable with numbers and maths, horses-for-courses......

You can find Steve's book that @Adreneline referred to here:

https://www.firstlightoptics.com/books/dark-art-or-magic-bullet-steve-richards.html

 

M51_PI_Crop.thumb.jpg.889e24b20b37c8f4c160fe4ac958bed2.jpg

 

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4 hours ago, Oddsocks said:

The image has some horizontal banding, typical of some Canon Cameras. If you intend to stay with Photoshop and are using the full photoshop program then have a look at adding a set of action plug-ins specifically developed for astrophotography such as Noel Carboni's Astronomy Tools Action Set, or Annies Astro Actions. Noels Tools contains a nice horizontal and vertical de-banding action and several other useful tools such as light pollution gradient removal, star colour boost and background noise reduction amongst others.

http://www.prodigitalsoftware.com/Astronomy_Tools_For_Full_Version.html

http://www.eprisephoto.com/astro-actions

You can find Steve's book that @Adreneline referred to here:

https://www.firstlightoptics.com/books/dark-art-or-magic-bullet-steve-richards.html

 

M51_PI_Crop.thumb.jpg.889e24b20b37c8f4c160fe4ac958bed2.jpg

 

Thanks for the processing and detailed steps, much appreciated!

That is interesting about the horizontal banding! I am indeed using a Canon(EOS1200d). I will certainly take a look at those plugins and books too!

Have only viewed all the above processing attempts on my phone so far, can't wait to flick through them om the laptop and compare. Really is a stunning galaxy!

Thanks everyone

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f33n3y_m51.thumb.jpg.854eac7a61d8e11a7dfba549cbb2f263.jpg

Cropped and stretched in PixInsight. Mainly noise reduction, stretching and colour saturation. No fancy sharpening, etc. The image needs a lot more data for that.

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