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The Dumbbell nebula


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I saw a few great examples of the Dumbbell nebula already this season so I took some time to process several times the data I have on it. I have almost decent narrowband data taken with the 130PDS, but with bad tracking and horrible RGB data taken the 150PDS and DSLR, but with good tracking. I could reduce a bit the effects of the bad tracking by applying deconvolution to the NB channels and I only took the highlights of the RGB image and applied it to the NB stars. The 150PDS had it's secondary mirror replaced with a larger one and it's not yet fully tweaked. The stars through it look rectangular, not even square. That was a real pity, I took it under a really dark sky. At ISO800 and 600s exposure, the red channel didn't even leave a space to the left of the histogram.

In the end, I combined 8h of OIII, 7h of Ha (300s exposures, ASI1600, 130PDS, AZ-EQ5) and around 2h of RGB (180s exposures @ISO400, DSLR, 150PDS on EQ6-R).

I'm not really sure how the background looks, my screen is an IPS and decently calibrated, but I need to see the image on a worse screen where all the background issues pop out.

This area seemed to benefit a lot from using masked stretch, the stars colours look very vivid to me.

Unfortunately, I don't have much more time to shoot this target as it hides behind the house and, if I don't get at least 3 more hours with the properly tweaked 150PDS, I find no reason in starting over the stacking and processing.

Other thoughts about improving the image?







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Thank you, Steve, Neil! I'm glad you like it!

The extended blue halo is the oxygen emission, indeed. It's also surrounded by hydrogen, you can see it more visible to the right, but also a bit to the nebula's top-left corner. My data is not allowing me to stretch it much further, it's already super stretched. As usual, more data would help.

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