A tiny nebula and the Milky Way's twin

On July 25 I took the opportunity to take advantage of some relatively clear skies (for a change) and point my scope to NGC 7331. The reason I picked this galaxy at this time is because a supernova was recently discovered very close to the nucleus of the galaxy (and because I wanted to compare my recent image of NGC 7331 with one I took back in 2017).

NGC 7331

Here is my latest image of NGC 7331.

NGC 7331 - July 25, 2025
EdgeHD11/ASI2600mm - LRGB - 3h 36m integration time

NGC 7331, often dubbed the “Milky Way’s twin,” is a striking unbarred spiral galaxy located about 40 million light-years away in the constellation Pegasus. With its elegant, moderately wound spiral arms and bright central bulge, this galaxy spans roughly 120,000 light-years, making it slightly larger than our own Milky Way. Viewed at a steep angle of 77 degrees, NGC 7331 presents a dramatic, elongated profile that reveals intricate dust lanes and a subtle asymmetry in its disk. Its core rotates in the opposite direction to the surrounding disk—a rare and intriguing feature. It is the brightest member of the Deer Lick Group.

The Deer Lick Group is an apparent galaxy grouping centered on NGC 7331. Surrounding it are several smaller galaxies—NGC 7335, NGC 7336, NGC 7337, and NGC 7340—that appear nearby in the sky but are actually much farther away, lying between 294 and 365 million light-years distant. This visual proximity is a result of line-of-sight alignment rather than gravitational association, rendering the “Deer Lick Group” a false group. Despite lacking physical interaction, the composition offers valuable insight into galactic structure, morphology, and scale.

Although a bit difficult to see the supernova, SN 2025rbs, is just to the right of the galaxy's central core. The image below, enhanced with high dynamic range (HDR) processing and cropped to show just the central core, shows the bright blue supernova glowing about as bright as the whole nucleus of the galaxy. 

SN 2025rbs was discovered on 14 July 2025 and it is a type Ia supernova. A supernova is a massive explosion that occurs when a star reaches the end of its life and can no longer hold itself together. In just a few moments, it releases an enormous amount of energy, briefly shining brighter than entire galaxies.

NGC 6210 - Turtle Nebula

NGC 6210, also known as the Turtle Nebula, is a striking planetary nebula located about 6,600 light-years away in the constellation Hercules. This cosmic sculpture marks the final breath of a sun-like star, which shed its outer layers to form a glowing shell of gas and dust. The nebula’s inner region resembles a delicate bluish “nautilus shell,” pierced by symmetrical jets of material streaming outward, while its fainter outer structure evokes the shape of a tortoise shell.

I'm not sure I see all the resemblance to a turtle but so be it.

NGC 6210 - The Turtle Nebula - July 4, 2025
EdgeHD11/ASI2600mm
LRGB - 1h 50m integration time

Although there is probably some significant Ha and Oiii signal in the object I chose not to capture that NB data since the broadband signal was so strong and I didn't want to spend the imaging time on this object.