M81 and M82 form one of the most iconic and visually striking galaxy pairs in the northern sky, located in the constellation Ursa Major at a distance of approximately 11.8–12 million light-years from Earth. Known respectively as “Bode’s Galaxy” and the “Cigar Galaxy,” they occupy the same field of view and are a favorite target for both visual observers and astrophotographers. This image, captured using the LRGB technique with an additional H-alpha channel and a long total integration time under dark skies in southern Spain, reveals not only the intricate details of both galaxies but also the faint, dusty structures in the background sky known as the Integrated Flux Nebula (IFN). These subtle filaments, illuminated by the diffuse light of the Milky Way, add a ghostly beauty to the scene and hint at the complexity of the interstellar medium surrounding us.
M81 is a grand design spiral galaxy of morphological type SA(s)ab, featuring well-defined spiral arms and a bright central bulge. Its companion, M82, presents a stark contrast: a disturbed, irregular galaxy shaped by gravitational interactions with M81 during their last close encounter some 300 million years ago. This past interaction triggered intense starburst activity in M82, making it one of the prototypical “starburst galaxies” in the local universe. Thanks to the use of an H-alpha filter and the application of continuum subtraction in PixInsight, I was able to isolate and enhance the hydrogen emission from M82, revealing its iconic red plumes — powerful galactic superwinds blowing hot gas and dust far out of the galaxy’s plane. These energetic outflows are driven by stellar winds and supernovae associated with the high rate of star formation at M82’s core. The addition of H-alpha data significantly enriched the red channel of the final image and brought the galaxy’s dynamic nature to life.
AstroBin: https://app.astrobin.com/i/vkbrcq
In the background of this cosmic duet lies the ethereal glow of IFN — faint clouds of interstellar dust and gas that reside well above the plane of our Milky Way. Though not physically associated with M81 or M82, these structures reflect the combined starlight of our galaxy, making them a rare and challenging target for astrophotography. Their presence in this image bridges vast cosmic scales: from local galactic cirrus just a few hundred light-years away, to massive spiral galaxies over 12 million light-years distant. From an astrophysical perspective, this image highlights the interplay between local and extragalactic structures — a visual and scientific reminder that the night sky, even in its darkest corners, is filled with hidden complexity. Capturing both the energetic outbursts of distant galaxies and the faint whisper of interstellar dust in our own backyard is what makes deep-sky imaging such a rewarding pursuit.
Technical information:
- LRGB – 4 x 75 x 300s & Ha – 50 x 600s (total exposure time a little bit more than 33 hours)
- TS APO 140/910 with field flattener and camera QHY268M and with Astronomik filters (Ha 6nm)
- iOptron mount CEM70EC with William Optics GuideStar 61/320 & ASI178MM