The more immediately impressive of the two galaxies is Bode’s (M81). It was discovered by the German astronomer Johann Elert Bode in 1774. In terms of size and structure, we think Bode’s Galaxy is fairly similar to our own Milky Way Galaxy.

It has a bright, compact core, which is good news for urban astrophotographers because that means it can cut through light pollution relatively well. It’s the opposite for the spiral arms though, which are quite faint. Careful processing is needed to ensure they stand out and don’t become overpowered by the darker background.

Hidden within the core is a supermassive black hole with a mass around 70 million times greater than that of our Sun. This can’t be seen in my image, though. What is visible though are areas of hydrogen, shown as red areas in the spiral arms. These are regions of star formation. I’m impressed with how my Optolong L-Quad Enhance filter has allowed their signal to come through so strongly.

The frenzy of the red hydrogen contrasts well with the bright but smooth rest of the galaxy, making it a good target to image from a city. A long focal length telescope definitely helps.

Look just above M81 and you’ll notice a faint, smudged patch that doesn’t quite look like a normal galaxy. This is Holmberg IX, a small and relatively young dwarf galaxy orbiting M81. It was first identified in the 1950s by the astronomer Erik Holmberg.

Holmberg IX has an unusual origin. It is thought to be a tidal dwarf galaxy, formed from material torn out of M81 during a close encounter with M82. That same interaction is believed to have triggered M82’s intense burst of star formation. Over time, some of the stripped gas and stars condensed to form Holmberg IX.

The galaxy has extremely low surface brightness, which makes it difficult to detect from light polluted locations. Even so, it’s possible to capture not just the diffuse glow of Holmberg IX, but also a scattering of young blue O and B type stars that belong to the dwarf galaxy itself. I’m happy to have captured these in my photo.

If you’re imaging M81 and hoping to record Holmberg IX, take care with noise reduction. Apply too much and the dwarf galaxy can easily be smoothed away into the background.