NGC 5223 in Canes Venatici
April 2025 - Galaxy of the Month
April skies give us the last chance to see fainter galaxies before the end of astronomical dark in early May. Mark Stuart suggested to me that the trio of galaxies in Canes Venatici around NGC 5223 might make an interesting GOM. All three of the galaxies, NGC 5223, NGC 5228 and NGC 5233 were discovered by William Herschel in 1785.
It is suggested that NGC 5223 may contain an AGN due to the fact that it contains a bright X-Ray source at its centre. It is classified as an elliptical galaxy, possibly E2. NGC 5228 is suggested to be a lenticular galaxy of type S0 and also a radio source. NGC 5233 is a spiral. There is an ESO image which suggests this is a blue dwarf galaxy with a large star cluster, but I am not sure if they have the right designation associated with this observation. There certainly does not appear to be any confusion in the NGC as to its identification. NGC 5233 is also suggested to have an AGN of the LINER type.
It is unclear whether this is a physical group as the distances to them are either not defined or widely different, although the redshift based distances are similar so they could be a physical group. The whole field is also littered with other much fainter galaxies. The group has not been catalogued in either the LGG or WBL catalogues which suggests either it was too faint for them or it is not a true group.
Unfortunately, there is not much other information on the galaxies available so I apologise for the somewhat shorter GOM this month. All the galaxies appear to be somewhat smaller than our Milky Way galaxy.
The galaxies are fairly faint so the group is going to be challenging to see. The group is quite tight and all three galaxies will fit in the same field of view with a modern hyperwide (100 degree) high power eyepiece. The group does not make it into either Miles Paul’s Atlas of Galaxy Trios (available for free from our website) or Alvin Huey’s Galaxy Trios and Triple Systems guide (available for free from Alvin's website).
William Herschel discovered the group with his 18.7” speculum metal mirror reflector, although he described all three of the galaxies as very faint, it probably needs at least a 40-45cm telescope to see the main components. It would be interesting to see what size telescope is needed to see the other galaxies in the group. Perhaps as expected there are no observations of the group in any of the standard references. Steve Gottlieb described them all as faint with his 17.5” Dobsonian. It would be interesting to know what size telescope is needed to see the small edge-on UGC 8547 as I note that Steve Gottlieb did not include it in his UGC notes.
Owen Brazell - Galaxy Section Director
If you'd like to try out the Clear Skies Observing Guides (CSOG), you can download observing guide for the current Galaxy of the Month without the need to register. CSOG are not associated with the Webb Deep-Sky Society but the work of Victor van Wulfen.
