Messier 81 and Messier 82 are a pair of interacting galaxies in Ursa Major, roughly 12 million light-years away. They have been influencing each other gravitationally for over a billion years, and that interaction is what turned M82 into a starburst galaxy, driving the outflows we see today.
The project
M81 and M82 were the Deep Sky Collective’s very first project, so going back to them was a chance to measure how far our techniques have come, with a bit of an emotional connection too. M82’s bipolar H-alpha outflow was again the main point of interest, but this time we also captured OIII, as data from our NHZ widefield project suggested extensive OIII emission in the outflow. We also widened the framing to include NGC 3077 and its active core, and part of the UMa Arc.
Imaging ran for about four months from March 2026, followed by a couple of months of pre- and post-processing. Thirteen people worked on the project, reaching a total of 1157 hours and 43 minutes of integration, a new record for the DSC. About 500 hours are H-alpha, around 185 hours OIII, and the rest LRGB.
What the data revealed
The depth of the data shows the stream connecting M82’s northern H-alpha cap to the main outflow in much greater detail, which we describe as an intermediate H-alpha cap. The OIII emission appears to lead the H-alpha in the outflow, and to our knowledge this is the first image of M82 showing the OIII stream component. We also present evidence for a possible southern counterpart to the H-alpha cap, although at this distance it could also be foreground cirrus, and spectral analysis would be needed to confirm it. All narrowband data is continuum subtracted.
Credits
Tim Schaeffer: coordination and photography
Adrien Keijzer: stacking
Steeve Body and Nicolas Puig: editing
Patrick Ogle: scientific advisor
Additional photographers: Justin P., Jasper Capel, Stephen Guberski, Carl Björk, Brian Valente, Akash Jain, Max Kuster, Jeff Schilling and Andrej Kovak.
Explore the full-resolution image in the Deep Sky Collective gallery and on AstroBin.
