Hemisphere:  Northern  ·  Constellation: Canis Minor (CMi)  ·  Contains:  PK214+07.1
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Abell 20 with PixInsight Photoshop WorkFlow, 


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Abell 20 with PixInsight Photoshop WorkFlow

Imaging telescopes or lenses: Stellarvue SVT 130T

Imaging cameras: SBIG STT 8300M

Mounts: Astro-Physics Mach1AP GTO CP4

Guiding telescopes or lenses: Stellarvue SVT 130T

Guiding cameras: SBIG STT 8300M

Software: Software Bisque TheSky X Professional  ·  photoshop  ·  Starnet ++  ·  CCDWare FocusMax V.4  ·  PixInsight  ·  Straton Destar 2.0  ·  Topaz Denoise AI  ·  3D LUT Creator  ·  Maxim DL  ·  EQMOD  ·  DC-3 Dreams ACP Observatory Control Software  ·  Astro-Physics Command Center (APCC) Software  ·  Annie's Astro Actions Version 7.0

Filters: Astrodon H-alpha 5nm  ·  Astrodon O-III 5nm

Accessory: Moonlite Nitecrawler 3.5  ·  Tolga Astro Alnitak Flat-Man Electroluminescent Flat Fielding Device

Dates:Feb. 4, 2021

Astrodon 3nm OIII 31mm: 6x1800"
Astrodon Blue Tru-Balance E-Series Gen 2: 8x240"
Astrodon Green Tru-Balance E-Series Gen 2: 8x240"
Astrodon Red Tru-Balance E-Series Generation 2: 8x240"

Integration: 4.6 hours

Avg. Moon age: 21.88 days

Avg. Moon phase: 52.83%

Astrometry.net job: 4200389

RA center: 7h 22' 57"

DEC center: +1° 45' 36"

Pixel scale: 1.222 arcsec/pixel

Orientation: -1.448 degrees

Field radius: 0.130 degrees

Resolution: 554x526

Locations: Stanford Faculty Observatory (Bortle 6 SQM 18.6), Stanford, California, United States

Data source: Own remote observatory

Remote source: Non-commercial independent facility


There is not much information on this one but there is a nice discussion of the O-III versus H-alpha filtering here:

Color and Filter Information

I decided to put up my entire workflow on this object since it was very clear what was going on (see the "A" image.

The A image has the original RGB images on top and you can see the light Blue, which is what i do to get the basic color right, i.e. this is not red but blue primarily.

The second row down is the O-III using Rob's technique I normalize (dnsLinearFit) the O-III then add in the appropriate percentages of the O-III to the G&B to get new G &B images that reflect the actual color of the O-III.

At the bottom these are added together to form the RGB image, which is photometrically color corrected in PI. The images on the right and Topaz AI denoised in PS and then GAME masked in PI to isolate the PN. The last images has the bright star enhanced/fixed with Star Spikes Pro 4.

Note how few images are needed here when Topaz AI is used to denoise. I do a light denoising in PI when the images is still linear (fuzz removal).


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.

It turns out to my surprise most of these are visible with my Stellarvue 130mm (5-inch) SVX.

Bottom line there are 79 imagable Abell Nebula of which I have imaged 38.

This is my 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.

These are some useful Abell relevant sites:

Color and Filter Information

Images by Season and More Filter information in German