Celestial hemisphere:  Southern  ·  Constellation: Pavo (Pav)  ·  Contains:  NGC 6744
Getting plate-solving status, please wait...
NGC 6744 - HaLRGB, Niall MacNeill
Powered byPixInsight

NGC 6744 - HaLRGB

Getting plate-solving status, please wait...
NGC 6744 - HaLRGB, Niall MacNeill
Powered byPixInsight

NGC 6744 - HaLRGB

Equipment

Loading...

Acquisition details

Loading...

Description

This is a complete reprocess of my dataset for NGC 6744. I did a much better job this time, I hope you agree.

As the first deep sky object I captured with good equipment, I am very fond of this object. I have spent so long int I have become lost in the intricacies of its beautiful structure.

The previous versions was a repost and as a completely separate image from my first RGB version, since the incorporation of the Luminance and Ha channels makes for a very different image.

Data acquisition: 20-07-23 to 20-09-11

Red 60 x 3mins

Green 68 x 3mins

Blue 67 x 3mins

Lum 96 x 3mins

Ha 33 x 20mins

That alone was a big learning curve for me and my thanks to Barry Wilson and Rodney Watters for their help and guidance. I still have some way to go to fine tune my DSO imaging, but it was pleasing to have finally produced an image of a galaxy with the Ha component included.

I made a super Luminance from the Luminance and RGB data and that effectively has 20 hours of data capture, which made for a very good SNR. I used the NBRGBCombination script in PI to good effect in order to incorporate the Ha data, although I had to do a lot of work to lose the gradients in it. I then incorporated the Luminance data, which I had previously deconvolved. The HDRMT process produced a large increase in contrast, but I found it too much so blended it back with the original at a ratio of 67:33 Original to HDRMT. I still have a lot to learn to get the best out of these processes but they are very powerful and can really enhance the image.

The colour of the central bar shows the yellow of the older stars but it was not as intense as I had expected. (Now fixed)

NGC 6744 was the first galaxy I started imaging with my SBIG 16803 last years, so I am delighted to have at last completed imaging this southern beauty.

I was also pleased to see some structure coming through in the satellite galaxy NGC 6744A. I saw a recent image of this galaxy, where the author stated that the satellite galaxy is attached to one of the galaxy's spiral arms. I don't think this is the case and it is more likely a trick of perspective. I assume it is sitting somewhat out of the plane of the main galaxy and just lines up with the spiral arm by coincidence. Does anyone have any different perspectives on that?

Comments

Revisions

  • NGC 6744 - HaLRGB, Niall MacNeill
    Original
  • NGC 6744 - HaLRGB, Niall MacNeill
    B
  • Final
    NGC 6744 - HaLRGB, Niall MacNeill
    C

B

Description: This is a complete reprocess of this image.
I struggled to get the colour right as the Narrow Band RGB Combination tool, whilst bringing through the Hydrogen Alpha, messes with the colour of the galaxy. I was able to create a mask and bring in just the Ha from the combination image into the LRGB image. Lo and behold, as I wound up the saturation, the beautiful blue of the hot young stars in the spiral arms came though as did the yellow/ orange of the core, where older stars reside. I also wound back the Ha to give the enhancement of these areas without it being too garish. As I did this I found I needed to mask the stars to prevent them being too intense in colour. I have more subtly processed the image to enhance the fine structure in the spiral arms.
I have tried some new tools to subdue the stars which can be a problem at these long focal lengths. Thanks John Hayes.

Uploaded: ...

C

Description: Per Geof's feedback, saturation backed off.

Uploaded: ...

Sky plot

Sky plot

Histogram

NGC 6744 - HaLRGB, Niall MacNeill