M106This is a tight crop, but I love the various galactic gems in this area - NGC 4217 in particular. While included in the Messier catalogue, M106 was discovered by a different "M" - Pierre Méchain. It is a Seyfert galaxy, and its water-maser has helped calibrate the cosmic distance ladder.
I first imaged M106 back in 2022 on a very hazy night, but decided to give it another go this year, having been inspired by several excellent images by my peers (
pcyvr,
Tom Gray,
wsg,
Nick Large) . With dwindling dark as summer approached, I devoted 6 nights to capturing 12+ hours. A recent software update for my ASIAIR reset the dithering distance to 1px which I didn't notice until night 4, but increasing the distance helped clean up some of the walking noise.
Processing this image was a challenge, as something in the stacked FITS disagreed with GHS and all I was able to get out of it was a grey and nearly featureless image. I was able to use this to my advantage to stretch the surrounding space & stars separately, while using masked stretch to bring out the galaxies. I am delighted at the detail and colour in M106, and excited to finally share it!
WIDE FIELD WITH ANNOTATED CANDIDATE COMPANION GALAXIESWith so many faint (and not so faint) fuzzies in this data, I was curious as to which were companion galaxies for M106, and which were unrelated background galaxies mugging for the camera. I found that this information wasn't entirely well-documented for this particular galaxy, with some potential misinformation floating around the internet as well.
It seems that
NGC 4217 is widely considered to be a companion galaxy. Despite the fact that this is
noted in SIMBAD, I cannot find a single academic source to back this claim, and given the considerable distance between M106 and NGC 4217 (M106 is ~23 Mly away - NGC 4217 is ~60 Mly) I would be very surprised if this were the case. If you're reading this and you have more information on NGC 4217, and its possible long-distance relationship with M106, please comment!
I found two papers with information on companion or satellite galaxies for M106 (neither of them mention NGC 4217). As an amateur astronomer, my understanding of the content of both was limited to a degree (or several degrees!) but they clearly present the selection criteria and process for companion galaxy candidates, and it was from
A wide-field survey of satellite galaxies around the spiral galaxy M106 (E. Kim et al., 2011) that I drew a shortlist of 16 candidates, 9 of which I was able to resolve with my data.
I have included full-colour and monochrome-inverted annotated images showing the galaxies, with unresolved galaxies indicated (and in dimmer text). This is certainly not professional/academic grade data, and for several of the galaxies (I'm looking at you, KK 134) it's a bit of a stretch, but it was fun to play astronomer and put together these images. Perhaps with more integration time next galaxy season, I'll be able to show a bit more detail. Thanks for your interest!
Note. List of candidates are from E. Kim et al. (2011). Beneath each image is the field of view in arcseconds.REFERENCESE. Kim, M. Kim, N. Hwang, M. G. Lee, M.-Y. Chun, H. B. Ann. (2011). A wide-field survey of satellite galaxies around the spiral galaxy M106.
Monthly Notices of the Royal Astronomical Society, Volume 412, Issue 3, April 2011, Pages 1881–1894,
https://doi.org/10.1111/j.1365-2966.2010.18022.xScott G. Carlsten, Johnny P. Greco, Rachael L. Beaton, Jenny E. Greene. (2020). Wide-field Survey of Dwarf Satellite Systems around 10 Hosts in the Local Volume. The American Astronomical Society,
The Astrophysical Journal, Volume 891, Number 2,
https://iopscience.iop.org/article/10.3847/1538-4357/ab7758 
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