IC2574 is quite a faint object, so it was never a part of the New General Catalogue. It is a dwarf galaxy discovered by Edwin Foster Coddington in 1898 – hence its common name Coddington’s Nebula, though it is not a nebula at all. IC2574 galaxy is located in Ursa Major and is an outlying member of the M81 group of galaxies. The distance to this object was estimated at 12.8 million light-years.
The note sent by Coddington to the Astronomical Society of the Pacific was:
While examining some negatives which I obtained with the Crocker telescope on April 17 and 20, 1898, I discovered a large faint nebula not given in N.G.C., nor in the supplement to N.G.C., nor have I been able to find it in any of the more recent catalogues.
On the night of April 22nd, Professor Hussey and I observed it with 12-inch telescope, and found the position of its brightest condensation to be
RA = 10h 18m 7s
Dec = +69d 10.1m
referred to the mean equinox of 1860.0.
The telescope shows it to be large, irregular, very faint, and composed of a number of condensations.
On May 19th I obtained an additional photograph of this region with an exposure of four hours. This shows the different condensations to be connected by faint nebulous matter, and the whole to extend an area fully 4′ in width and 12′ in length.
I collected subframes to the image above during several nights in February 2025. The total amount of exposure time was 10 hours, so much more than Coddington did in 1898. His telescope was larger, but my camera is much more sensitive than negative film, so the final outcome is probably better. I wrote “probably”, because I have not found the images made by the IC2574 discoverer in 1898.
The IC2574 galaxy is irregular due to a lack of organization of structure. These galaxies are thought to resemble some of the earliest that formed in the Universe. They serve as useful “living fossils” for studying the cosmos’ evolution. Pink bubbles in the IC2574 come from the supernova explosions – the color of these shells is from the hydrogen gas irradiated by newborn stars.
Coddington’s Nebula is not the only interesting object in the picture. You may notice the gray IFN (Integrated Flux Nebula) patches in the background. This is interstellar dust illuminated by the distant stars, so its brightness is really low. Also, the concentration of this dust is low, so there are large and distant galaxy clusters visible in the background as groups of yellowish small objects – most of them are galaxies. Galaxy clusters Abell 968, 981, 998, 1005 are spread across the image, and the enlarged parts of these clusters are presented below.
There are many distant interested galaxies in the frame, I cropped some of them and pasted them below inverted – so their shape and features are better visible. The region around IC2574 was not cataloged by the SDSS survey, so there is no spectroscopic data available for faint objects here.
The limiting magnitude of this image is 22.4mag at SNR=7, which is quite impressive for data captured under the suburban sky with a modest 130mm aperture.
Image technical data: Date: February 2025 Location: Nieborowice, Poland Telescope: TS Photoline 130/910 Corrector: TS FF/FR 0.8x Camera: QHY268M Mount: EQ6 Guiding: ASI290MM + Evoguide ED50 Exposures: LRGB 650:120:80:100 minutes Conditions: Bortle 6, transparency and seeing good
