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Go Back   IceInSpace > Images > Deep Space

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  #1  
Old 13-06-2018, 07:47 PM
furgle (Adam)
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Barred Spiral NGC 5921

I'm not too sure if I'm happy with the colour balance on this one, but I've been playing with it for way too long


Higher resolution here



Image:

  • 63x 450s Red
  • 16x 450s Red
  • 16x 450s Green
  • 18x 450s Blue
Total integration 14 hours 8 minutes.
Hardware:

  • Celestron 11" Edge HD
  • Skywatcher EQ8 Pro mount
  • QSI 683-ws8 Camera @ -15°C
  • Astronomik Typ2c Luminance, Deep Sky RGB filters
  • Starlight Xpress Active Optics
  • Starlight Xpress Lodestar X2 Autoguider
  • Innovations Foresight On Axis Guider
  • Starlight Instruments Focus Boss II
Location:

  • Orange zone in Brisbane, Australia. (Bortle 7)
  • Imaged over 6 nights, new moon.
Software:

  • Planning & camera alignment with Aladin 9
  • Captured with AstroArt 6
  • Guiding with PHD2 + PHD_Dither
  • FocusLock live focusing
  • CCDInspector: Image analysis & rejection
  • CCDStack 2+: Calibrate, align, stack.
  • PixInsight: Dynamic background extraction, noise reduction, deconvolution, combine LRGB, color calibration, background neutralization, HDR multiscale transform, curves, local historgram equalization, non-linear stretch
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  #2  
Old 13-06-2018, 08:44 PM
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Geoff45 (Geoff)
PI rules

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There’s good detail in that pic Adam, but as you mentioned the colour doesn’t seem quite right. Did you try the PhotometricColorCalibration in PI?
Geoff
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  #3  
Old 13-06-2018, 08:55 PM
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strongmanmike (Michael)
Woohoo it's clear

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Apart from the colour, which looks a little purpley...wow, what a galaxy love it!...look at those arms, amazing top shot Adam

Mike
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  #4  
Old 13-06-2018, 09:30 PM
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gregbradley
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A nicely detailed image. I wonder if the Milky Way looks like this.

Greg.
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  #5  
Old 13-06-2018, 09:36 PM
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Atmos (Colin)
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Very nice galaxy shot, considering its size you've captured a lot of detail in the spiral arms. Bit purple in the galaxy (but not the stars) but the data looks great
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  #6  
Old 14-06-2018, 07:30 AM
furgle (Adam)
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Quote:
Originally Posted by Geoff45 View Post
There’s good detail in that pic Adam, but as you mentioned the colour doesn’t seem quite right. Did you try the PhotometricColorCalibration in PI?
Geoff

Thanks, no matter what settings I tried, PCC could not find a star in the image. I've never had an issue with it before. Astrometry.net solved it, TheSkyX solved it, even PixInsight's ImageSolver script solved it. I have no idea why.


Quote:
Very nice galaxy shot, considering its size you've captured a lot of detail in the spiral arms. Bit purple in the galaxy (but not the stars) but the data looks great
Originally I had manually tried to shift the arms towards blue, then I saw Adam Block's rendition. There's definitely some red in the arms, but I guess I didn't have the aperture to separate the blue & red properly.
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  #7  
Old 14-06-2018, 08:03 AM
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RickS (Rick)
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I'm not a fan of the purple but it looks nice otherwise.

Quote:
Originally Posted by furgle View Post
Thanks, no matter what settings I tried, PCC could not find a star in the image. I've never had an issue with it before. Astrometry.net solved it, TheSkyX solved it, even PixInsight's ImageSolver script solved it. I have no idea why.
You can load the plate solve from an image solved with ImageSolver into PCC. Just use the button that says something like "Acquire from image".

Cheers,
Rick.
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  #8  
Old 14-06-2018, 09:32 AM
furgle (Adam)
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Quote:
Originally Posted by RickS View Post
I'm not a fan of the purple but it looks nice otherwise.



You can load the plate solve from an image solved with ImageSolver into PCC. Just use the button that says something like "Acquire from image".

Cheers,
Rick.

Thanks Rick, that worked.

Now to find some more time to re-edit.

One very interesting thing I just discovered that may be affecting my colour; every tutorial I've seen says to use linear fit on your R,G,B subs, but then when I use PCC, everything is red biased. If I don't linear fit, PCC gives me better colour.
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  #9  
Old 14-06-2018, 09:59 AM
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RickS (Rick)
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Quote:
Originally Posted by furgle View Post
One very interesting thing I just discovered that may be affecting my colour; every tutorial I've seen says to use linear fit on your R,G,B subs, but then when I use PCC, everything is red biased. If I don't linear fit, PCC gives me better colour.
Adam,

You don't need to match the colours with LinearFit if you're going to do some sort of colour calibration. It does help to do background neutralization before running PCC, either with DBE or the BackgroundNeutralization process.

Cheers,
Rick.
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  #10  
Old 14-06-2018, 10:13 AM
furgle (Adam)
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Quote:
Originally Posted by RickS View Post
Adam,

You don't need to match the colours with LinearFit if you're going to do some sort of colour calibration. It does help to do background neutralization before running PCC, either with DBE or the BackgroundNeutralization process.

Cheers,
Rick.

Thanks,


Much appreciated, as always.
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  #11  
Old 14-06-2018, 10:47 AM
Stevec35 (Steve)
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Apart from the purple colour that's a really good image of a spectacular galaxy that I haven't seen before.

Cheers

Steve
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  #12  
Old 14-06-2018, 07:57 PM
topheart
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Great target!!
Cheers,
Tim
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  #13  
Old 15-06-2018, 05:50 PM
kosborn (Kevin)
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Quote:
Originally Posted by furgle View Post
One very interesting thing I just discovered that may be affecting my colour; every tutorial I've seen says to use linear fit on your R,G,B subs, but then when I use PCC, everything is red biased. If I don't linear fit, PCC gives me better colour.

Is linear fit necessary? I've read that an unlinked screen transfer function works just as well. I'd be interested to know what the PI gurus think.


Kevin
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  #14  
Old 15-06-2018, 07:10 PM
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Slawomir (Suavi)
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Very nice detail Adam
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  #15  
Old 16-06-2018, 07:45 AM
Placidus (Mike and Trish)
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The shape and form and depth in the spiral arms is delightful.
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