There has not been a lick of clear skies for me since Thanksgiving week, and I have become mighty bored. One of my favorite images seemed like a good candidate to rework since I have new tools and new knowledge.
I originally took 25 hours of data on Messier 51 back in May of 2021, but I went very heavy-handed on the original take. This time, I wanted to improve the detail using the new RC Astro tools, make it a little more natural looking, and really bring out the halo of lost stars from this galactic merger. I’m very pleased with this image,
Commonly called Messier 51, the “object” consists of two galaxies that are in the process of merging. Messier 51a, the prominent face-on spiral galaxy, and NGC 5195, the dwarf elliptical galaxy, are 31 million and 25 million light years away, respectively. It is thought that NGC 5195 has passed through the disk of M51a twice, resulting in the prominent spiral arms. I paid specific attention to reveal the crown-like tidal tails that consist of stars being thrown from the galaxies, with the upper prong being a bit bluer than the bottom, suggesting those stars are from M51a. The full resolution image reveals some incredible detail in the structure of M51a.
Here is an annotation of the image with the Messier, IC, and PGC catalogues,
The galaxy pair in the upper left really draws the eyes, so I investigated them,
IC 4263 shows very prominent detail and structure in my image. It is 2.17 arcminutes long and has a redshift of z = 0.00905. This makes it about 138 million light years away and 87,000 light years in diameter. PGC 2289565 is 0.70 arcminutes long and has a redshift of z = 0.07500, making it about 1.09 billion light years away and 221,000 light years in diameter, a real big boy!
Previously shown off, the farthest object I have imaged and verified is a quasar below the target. It is a quasar that took 11.8 billion years of light travel time and was receding away from us at almost three times the speed of light. It’s magnitude was 20.3, which is decently dim for an amateur setup. Using the SDSS R9 catalog, the image contains 8409 objects between 17 and 22 magnitude. That means that many of the point-like objects in this image are actually extremely distant, “primordial” galaxies. From a visual inspection, it seems that the magnitude limit of this image is around 22.2. As a frame of reference, the brightest star in the sky is Sirius at a magnitude of -1.33, which is 2.6 billion times brighter than the dimmest object I was able to resolve. It’s always immensely wonderful what I am able to see in this grand universe from my backyard.
