Abell 78 is a planetary nebula located in the constellation of Cygnus. It has a fainter halo consisting mostly hydrogen, and an inner elliptical ring that is mostly made of helium.The central star of the planetary nebula has a [url=mw-redirect=https://en.wikipedia.org/wiki/Spectral_type]spectral type[/url] of [WC5], similar to that of a carbon-rich Wolf–Rayet star.

Above from Wikipedia... there are several very nice examples on Astrobin with lengthy write-ups...

Very difficult processing.  NB Assistant favored the blue too much for my taste, but that is what does come through in RGB. 

I went for standard HOO processing but then use GHS to carefully aligh the RGB peaks and then stretch.  This brought out a lot of detail.  GHS Forum Discussion

I did not get much milage from Topaz AI techniques.  There was already a lot of detail.  Colors saturation contrasted and increased with 3D LUT. 

Previous version same scope but CCD camera and no AI processing


Abell 78

GENERAL NOTE ON ABELL (and other) PLANETARY NEBULA>>>>>>>>>>>>>

From Wikipedia:

The Abell Catalog of Planetary Nebulae was created in 1966 by George O. Abell and was composed of 86 entries thought to be planetary nebulae that were collected from discoveries, about half by Albert George Wilson and the rest by Abell, Robert George Harrington, and Rudolph Minkowski. All were discovered before August 1955 as part of the National Geographic Society – Palomar Observatory Sky Survey on photographic plates created with the 48-inch (1.2 m) Samuel Oschin telescope at Mount Palomar. Four were later rejected as not being planetaries: Abell 11 (reflection nebula), Abell 32 (red plate flaw), Abell 76 (ring galaxy PGC 85185), and Abell 85 (supernova remnant CTB 1 and noted as possibly such in Abell's 1966 paper). Another three were also not included in the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (SEC): Abell 9, Abell 17 (red plate flaw), and Abell 64. Planetaries on the list are best viewed with a large aperture telescope (e.g. 18-inch (0.46 m)) and an OIII filter.

There is an Abell Group on Astrobin. 

This is my personal collection:

Planetary Nebula (Abell)

These are sorted by number and behind the Abell's are other miscellaneous PNs that I have imaged... I have a list of the 100 brightest.

This is Gary Imm great poster on the Abell's:

Gary's Poster

This is Jerry Macon's outstanding Abell Collection:

Jerry Macon's Abell Collection

These are some useful Abell relevant sites:

Color and IMHO Best Filter Information

Images by Season and More Filter information in German