NASA Astronomical Picture Of the Day
This is one of the world's most detailed image of NGC 6979, which is the part of the Veil Nebula supernova remnant in the constellation Cygnus known as Pickering's Triangle. This was my first astrophoto of the autumn season of 2015.
It took me over a year to complete this imaging project. NASA featured it as its Astronomy Picture of the Day (APOD) on 2015.09.17 at https://apod.nasa.gov/apod/ap150917.html.
The colors show the ionized elements hydrogen, sulfur and oxygen. S-II = Red; H-alpha = Green; and O-III = Blue. This color palette shows light from ionized hydrogen and sulfur as golden yellowish hues. The light from ionized oxygen is shown by bluish hues.
To me this photograph of complex gas filaments is marvelously beautiful in spite of the fact that it really is full of extremely violent cosmic energy. This is a gloriously beautiful beast.
An explanation written by a professional NASA APOD astronomer
"Chaotic in appearance, these filaments of shocked, glowing gas break across planet Earth's sky toward the constellation of Cygnus, as part of the Veil Nebula. The Veil Nebula itself is a large supernova remnant, an expanding cloud born of the death explosion of a massive star. Light from the original supernova explosion likely reached Earth over 5,000 years ago. Blasted out in the cataclysmic event, the interstellar shock waves plow through space sweeping up and exciting interstellar material. The glowing filaments are really more like long ripples in a sheet seen almost edge on, remarkably well separated into the glow of ionized hydrogen and sulfur atoms shown in red and green, and oxygen in blue hues. Also known as the Cygnus Loop, the Veil Nebula now spans nearly 3 degrees or about 6 times the diameter of the full Moon. While that translates to over 70 light-years at its estimated distance of 1,500 light-years, this field of view spans less than one third that distance. Identified as Pickering's Triangle for a director of Harvard College Observatory and cataloged as NGC 6979, the complex of filaments might be more appropriately known as Williamina Fleming's Triangular Wisp."