The large emission nebula complex in Cygnus catalogued as IC 1318, and known as the Butterfly Nebula. The main dark lane at left is LDN 889. The brigh
The large emission nebula complex in Cygnus catalogued as IC 1318, and known as the Butterfly Nebula. The main dark lane at left is LDN 889. The bright star at centre is Gamma Cygni, aka Sadr. Above it is the star cluster NGC 6910. The view is rendered in monochrome as it was shot on a moonlit night through a deep red filter in the light of H-alpha emission, prominent in such nebulas. This is a stack of 13 x 16-minute exposures with the SharpStar 94mm apo refractor at (with its reducer/flattener), and with the Canon Ra at ISO 1600 and equipped with an Astronomik clip-in 12nm Hydrogen-Alpha filter which lets through only very deep red light. The last few exposures were taken with a waning quarter Moon lighting the sky. Guided with the MGEN autoguider applying a dithering shift between each exposure to eliminate thermal noise when stacking the images. (Each sub-frame had a lot of thermal speckling, as when shooting in H-a with a colour camera only 1/4 of the pixels, the red ones, are recording any signal.) No darks or LENR employed. All stacking and alignment was with Photoshop. Faint nebulosity was brought out with luminosity-masked curves created with Lumenzia. ON1 NoNoise AI applied to the base stack. A mild application of Russell Croman's StarXTerminator plug-in backed off the stars within the regions of nebulosity to further enhance the nebula structures. StarXTerminator was applied selectively via the use of non-destructive layers, blend modes and masks. A mild colour grade was applied as a finishing touch to add the blue tint to the darks.
Size: 5400px × 3584px
Photo credit: © Alan Dyer / VWPics / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: -, -alpha., 02, 12nm, 6, 130, 1318, 6910, 94mm, ai, astronomik, astrophotography, b343, basic, butterfly, canon, clip-, colors, colour, croman, cygni, cygnus, dithering, edph, emission, filter, gamma, grade, grey, hydrogen, ic, ldn889, lumenzia, mgen, monochrome, ngc, nonoise, photography, photoshop, plug-, ra, ro, sadr, science, sharpstar, sky, starshrink, starxterminator, thermal, universe, vdb
