The M101 (Messier 101), also known as the Pinwheel Galaxy, is a face-on spiral galaxy located in the constellation Ursa Major. It lies approximately 21 million light-years away and has a diameter of about 170,000 light-years, making it significantly larger than the Milky Way. M101 is noted for its well-defined spiral arms and large population of H II regions, indicating active star formation. Its asymmetrical shape is thought to be the result of gravitational interactions with nearby galaxies. The Pinwheel Galaxy is a favorite among astrophotographers due to its expansive, detailed structure and vivid star-forming regions.

The M81 (Messier 81), also known as Bode's Galaxy, is a grand-design spiral galaxy located in the constellation Ursa Major. It is situated approximately 12 million light-years away and has a diameter of about 90,000 light-years, making it slightly smaller than the Milky Way. M81 features a bright central bulge and tightly wound spiral arms, which host numerous star-forming regions and dust lanes. As one of the brightest galaxies in the night sky, it is easily visible through small telescopes and is often studied for its structure and proximity. M81 forms a well-known galaxy pair with the nearby irregular galaxy M82.