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Galaxies galore in Leo
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In springtime, the delights of the myriad of galaxies to be found in Coma and Virgo are very tempting, but wait a little, and be sure to take in the many galaxies to be found in Leo first.

The most popular galaxy target in Leo is no doubt the 'Leo Triplet'--M65, M66 and NGC 3628. All fairly easy with even a small scope of 15cm or 20cm aperture, and will be nicely framed in a one degree field eyepiece, or slightly smaller. To get a better view of the galaxies do try and use more magnification, though, to tease out the details. These three galaxies are an actual physical group, lying about 35 million light years away, and may be part of our next target, the M96 group of galaxies, sometimes referred to as the Leo 1 Group.

M65 is a fairly standard spiral galaxy. M66 is a somewhat more interesting spiral, with deformed arms, and NGC 3628 is an edge-on spiral a little fainter than the Messiers.


M96 and M95 are companions separated by about 40 minutes of arc, with M105 some 50 minutes north of M96. M96 is a nice face-on spiral, while M95 is a notable barred spiral. M105 is a giant elliptical galaxy, the brightest of the M96 Group, and a fairly typical representative of its class.

Near to M105 is a further nice pair of elliptical galaxies, NGC 3384 and NGC 3389--both just a little fainter than M105 (mag 9.2) at around mag10 and mag 11--though NGC 3389 is thought to be a background galaxy and not a group member. Moving 1[degrees]20' North, we come to another bright group member, the elliptical galaxy NGC 3377 (mag 10.2).


All told there are probably more than 20 members of the group (including the Leo Triplet), and it would be interesting to try to see how many can be observed. Some are rather faint for visual observers, but should be within easy reach of imagers.

Not to be confused with the Leo 1 Group is the Leo Cluster, a more compact group of galaxies to be found at the west end of Leo, and also known as Abell 1367. This is unconnected with the M96 group, being around 300 million light years distant. These are all fairly faint galaxies and a bigger telescope will be needed to pick them up, but many should still be within easy reach of astro-imagers. The brightest of these are NGCs 3842 (mag 12.8), 3816 (13.5), 3861 (13.5), 3884 (13.5) and 3883 (13.4). There is a fairly bright star, HIP 57335 of magnitude 7.5, which makes a good locator for the cluster.


A further object for confusion is Leo I--a dwarf spheroidal galaxy. It is about magnitude 9.8, and lies close to Regulus, only 12 arcminutes away from Leo's brightest star. This makes it rather difficult to observe visually, and you will need to arrange your view to try to keep Regulus out of the field. It is also fairly spread out and diffuse, so a low power may help.


Leo I is part of our local group of galaxies, and is about 820,000 light years distant. It is well worth seeking out, as it is one of the furthest satellite galaxies of our own Milky Way.

Callum Potter, Director, Deep Sky Section

Source Citation   (MLA 8th Edition)
Potter, Callum. "Galaxies galore in Leo." Journal of the British Astronomical Association, vol. 123, no. 2, 2013, p. 114+. Academic OneFile, Accessed 21 Nov. 2018.

Gale Document Number: GALE|A357148015