IC 1318 – In the NW Wing of the Butterfly Nebula

OTA:……………….CDK17
Camera:………….FLI Proline 16803, 9 micron pixels, 0.64 arcsec/pxl
Observatory:…. Rodeo, NM (Bernard Miller)

EXPOSURES:                
…R: 14 x 900 sec.            
…B: 14 x 900        
…G: 11 x 900    
…L: 24 x 1200    
…O: 18 x 1800        
…H: 12 x 1800        
…S: 17 x 1800        
Total exposure: 40.5 hours

Image Width: 41 arc-minutes
Processed by Alex Woronow (2021) using PixInsight, Topaz, Luminar, SWT

This minimally ionized nebula is one wing of a nebula, sometimes called the "Butterfly Nebula." Actually, the fov does not include the whole "wing." Nebula must be named from visual observations or low-resolution images! To paraphrase a geologist I once knew, “if it’s a butterfly, where are the scales?” At the time, he was inquiring about the structure of the Rocky Mt. A speaker had likened the tectonic blocks of the Rockies to a stack of slippery fish, and the questioner wanted to know what part was the scales. Oh well, in every audience, there’s at least one!

This image contains the line emissions (freed from their accompanying background content) for the SHO narrowband filters mapped into and combined with their appropriate RGB counterparts. This allows the image to be color-calibrated using PixInsights star-color method.

A new AI star-removal tool is available as a PS plugin for those who can tolerate PS's pay structure. But it is also available for Affinity Photo, which is much cheaper than PS, and it has an extensive array of Astro-image-specific tools. (Affinity accepts PS plugins as if they were it's own.) Although the developer of StarXTerminator says the plugin is not compatible with Affinity, it works. The how-to-install can be found in the discussions here: https://www.cloudynights.com/topic/789257-new-ps-plug-in-for-removing-stars-starxterminator/ (it’s easy.) It works better on small/medium stars than StarNet, but it still leaves scars when removing more prominent stars. However, the developer of StarXTerminator appears committed to product improvement, unlike StarNet-stagnation. (BTW, Affinity has a reasonably effective in-painting tool.)

Anyway, the image now reveals the textures and structures in this part of the cloud. It appears to me that there's a correlation between the cloud color (degree of ionization) and the type and intensity of structures. The less ionized regions appear more ragged and striated. The red, ionized regions appear more blotchy than striated. There’s probably physics going on here!