NGC 6826
Awarded Picture of the Day by the Gruppo Astrofili Galileo Galilei (GrAG) apod.grag.org/2020/08/24/ngc-6826-the-blinking-planetary/
Published in the April 2021 and August 2021 issues of Astronomy Now Magazine
Published in the March 2022 issue of Astronomy Magazine
NGC 6826 is a planetary nebula in the constellation Cygnus.  It is commonly known as The Blinking Planetary. This stems from the faintness of the outer shell which is only visible when using averted vision. It is also known as Caldwell 15. With this image I wanted to tease out the structure of the shell, by combining both Ha and OIII data. The OIII signal is the stronger of the two, hence the resulting teal colour.
TARGET
Nomenclature: NGC 6826, Caldwell 15, The Blinking Planetary Nebula
Right Ascension: 19:44:48.2
Declination:  +50:31:30.3
Size: 27x24 arc secs (core) 2.2 arc minutes (halo)
Discovery: halo discovered by John Duncan in 1937
EQUIPMENT USED
Twin APM TMB LZOS 152 refractors
10Micron GM2000 HPS mount
Twin QSI6120 CCD cameras
Astrodon filters
IMAGE CAPTURE
5nm H-Alpha: 25 x1800 bin 1x1
3nm OIII: 120x30, 178x120, 12x600, 20x1800 bin 1x1
Red: 20x300 bin 1x1
Green: 16x300 bin 1x1
Blue: 15x300 bin 1x1
Total integration: 37.3 hours
Pixel scale: 0.533 arcsec/pixel
Field radius: 0.346 degrees
Capture dates: 1 June - 25 July 2020
Capture location:  Fregenal de la Sierra, Spain
IMAGE PROCESSING
Pre-processing: CCDStack2
Post-processing: Photoshop CS2