NGC: NGC 7293, The Helix Nebula by a New Approach

OTA: CDK24 f/6.5, Chile
Camera: Moravian 61000 Pro Mono
Observatory: Telescope Live
Date of Capture: Aug, '23
Date of Processing: Nov, '23

Exposures:
R: 16 x 300 sec
G: 13 x 300
B: 16 x 300
O: 40 x 300
Total Exposure time:11.5 hours
Image Width: 30 arc-minutes

Processing Tools:
1.    Commercial: PixInsight, Topaz (Studio2, Photo AI2), Photo Director 365, Aurora HDR, Luminar Neo, 3DLUT Creator, Aurora HDR
2.    Pixinsight Addons: NoiseXTerminator, BlurXTerminator, StarXTerminator, Normalize Scale Gradient
3.    My Scripts: NB_Assistant, AC_Restar, Subframe Weighting Tool (Excel w/ J. Hunt), ColorTweaker, LTweaker, AlphaComposite

Target Description:
The Helix Nebula is a Planetary Nebula formed when an intermediate to low-mass star sheds its outer layers and collapses eventually to become a white dwarf. That star is the blue one in the center of the nebula. I have discussed the reason for the inner blue and outer red regions; see my Astrobin posting on Abell 66. And like Abell 66, the Helix Nebula shows different structures in the Ha and OIII emissions. No surprise! The OIII is a much more energetic emission than the Ha. I decided the OIII provided a more interesting image detail base in this nebula.

Because the structure is all OIII, some of the Ha-dominated areas do not receive much brightness and appear foggy or as faint clouds. Oh, the things we do for detail!

Processing Description:
In addition to the subframes listed above, the purchased data set contained H, L, and SII subframes. Including those subs eliminated for quality reasons, the total number of subs exceeded 300. For this image, I used about 40% of the available subs.

This image utilizes several novel processing tools to best reveal the detail in the image…color was secondary to the principal objective. Processing in Topaz Studio, which provides sharpening, was done on the isolated OIII emission line, with the continuum radiation removed. This was a grayscale image. That image had the RGB color image projected onto it. This differs from the regular operation of using the detailed grayscale image as the luminance channel in an RGB image. Think of the projection process as viewing the OIII image through a gauze curtain containing the RGB image. This is a first attempt at that approach, and there remains much to try and to learn.

This approach better suppresses the effect of bright color in an image, which sometimes can suffocate our perception of structural detail, which grayscale renderings (or inverted grayscale renderings) best display. Although color detail is also a thing, I decided to emphasize the structural detail in this presentation. (And it is fun to experiment with alternative processing approaches.)

Statistics:
Distance: 650 ly
Apparent Magnitude: 7.6
Average Surface Magnitude: 22
Pixel Span at Target: 1B km

Alex Woronow