NGC 6070 in Serpens Caput
June 2025 - Galaxy of the Month
Our galaxy for this month is the near face on spiral galaxy NGC 6070 in Serpens Caput.
Discovered by William Herschel in 1786 it has the SA(s)cd classification and along with the fainter galaxies PGC 57350 and PGC 1175364 it forms a trio. NGC 6070 is also part of the galaxy group LGG 404 along with UGC 10288 and 10294. If LGG 404 is a true group then the galaxies are spread quite a way apart on the sky. The situation gets confusing but the three galaxies with NGC 6070 are also known as Holm 729.
NGC 6070 is thought to be about 92 million light-years away and if at that distance would have a diameter of about 105,000 light-years. It was one of the first light images for the SDSS. NGC 6070 itself is at magnitude 11.8 but the two companions are around 14.4 or so and will be a challenge for larger telescopes.
The three galaxies are not a physical system with the two PGC galaxies probably being about 580 million light-years away and part of another cluster. If they are this far out then they are probably quite large as well. PGC 57350 is also a double galaxy system, probably undergoing a merger.
The images in the UV from the GALEX satellite show that there is a lot of star formation going on in NGC 6070 and a couple of the brighter giant HII regions in the NE of the galaxy maybe visible and are in fact covered in Alvin Huey’s latest guide on Observing Extragalactic Objects Within Host Galaxies. It is worth noting that the two small companions are sometimes called NGC 6070B and C, although sources frequently change which galaxy is which.
For those that follow the Deep Sky Forum, NGC 6070 was included in both 2019 and 2022. NGC 6070 is also included in the Astronomical League's Herschel II list.
As the galaxy is close to face on it is likely that in most telescopes only the bright core may be seen. The spiral arms maybe seen with larger telescopes from dark sites. The group is very tight and will fit in the field of a high-power eyepiece and this may be the best way to see them, in particular to pick out the faint companions.
The group is also covered in Alvin Huey’s Galaxy Trios guide. The The Night Sky Observer's Guide Vol. 2 suggests that a 30—35cm scope will show the core and 40—45cm will show the core surrounded by a haze. Steve Gottlieb in his complete collection of NGC observations at Adventures in Deep Space suggests that a 24” telescope maybe required to see the companions, certainly to split the double pair whilst using a 48” will show them well.
It is likely that the 7th magnitude star nearby will impact on observations of the group. The star is a red star catalogued as Espin-Birmingham 449.
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.
