Bright enough to catalog, faint enough to disappear at a glance
Some galaxies hide in plain sight, their light so diffuse it seems to flicker in and out of existence at the eyepiece
NGC 6118 is a grand-design spiral of morphological type SA(s)cd, sitting near the very end of the spiral sequence, its arms wound loose and open around so slight a central bulge that it is nearly a pure disk of stars, gas, and vigorous star formation
It lies roughly 67 million light-years away in the constellation Serpens Caput, spanning about 5.1 arcminutes on the sky, which at that distance corresponds to a physical diameter near 100,000 light-years, close in size to our own Milky Way
The loosely wound arms are studded with brilliant blue-white knots where hot, massive young stars have recently ignited, interleaved with rose-colored emission from hydrogen clouds and darker lanes of obscuring dust that trace the spiral pattern inward toward the pale golden core
In 2004 a star in one of these arms reached the end of its life as supernova SN 2004dk, a type Ib explosion whose light briefly rivaled that of the surrounding star fields before fading over the following months
NGC 6118 carries the nickname the Blinking Galaxy among visual observers, a reflection of its low surface brightness, it slips from view under direct vision and returns with averted gaze, a reminder that some of the sky’s most structured objects often reveal themselves only to patience and dark skies
Imaged in LRGB on the ASA Astrosysteme AZ 1500, Camera Moravian C5A 150M, at Observatorio El Sauce, Chile
Image Acquisition and Processing: Mike Selby