M96 is the brightest member of the Leo I group of galaxies, which is also called the M96 group, and includes M95, M105 and a number of fainter galaxies.

It is believed that the bright inner disk is composed of a smooth yellow stellar population of old stars, which ends slightly beyond a ring of blue knots. These knots are probably clusters of young, hot stars. The galaxy also contains a significant amount of dust, which is apparently more concentrated on one side. In fact it is common that dust appears with greater contrast on the near side of a galaxy than on the far side, so this is a good indictaion as to which side is presented.

In the lower image M95 is on the left and M96 on the right.

The Owl Nebula, M97, is one of the fainter objects in Messier's catalog and is one of just four planetary nebulae within his catalog.

M97 is one of the more complex planetary nebulae with its appearance interpreted as a cylindrical torus shell with the projected matter-poor ends of the cylinder corresponding to an owl's eyes. This shell is enveloped by a fainter nebula of lower ionization. The mass of the nebula has been estimated to amount 0.15 solar masses, while the 16 magnitude central star is believed to be of about 0.7 solar masses. The nebula is estimated to have been formed approximately 6,000 years ago.

As often for planetary nebulae, the Owl is significantly brighter visually (9.7) than photographically (about 12.0), as most light is emitted in one green spectral line.

M98 is one of the fainter objects in Messier's catalog and one of the more difficult to observe. This is a beautiful spiral galaxy seen edge-on and, although situated in the southern part of the constellation of Coma Berenices, is a member of the Virgo Cluster of Galaxies.

Together with nearby situated M99 and M100, M98 was discovered on March 15th 1781 by Pierre Méchain and measured and catalogued by Charles Messier on April 13th 1781, immediately before finishing the third, final published edition of his catalog.

Displays nearly edge-on, M98 is a chaotic and diffuse disk, containing some blue regions of newly formed stars, and a huge quantity of occulting dust, which reddens considerably the light of the central small but bright nucleus.

M99 is another member of the large Virgo Cluster of Galaxies. A bright spiral galaxy, M99 rotates clockwise (the opposite direction from nearby M100). This galaxy is unusually asymmetric with three branches and the nucleus shifted to one end. One specualtion is that this asymmetry could be due to an encounter with another member of the Virgo Cluster.

It would not be surprising to find evidence to suggest that M99 has encountered a collision, because with a radial velocity of 2,354 km/sec, M99 has one of the largest red shifts of any member of the Virgo Cluster (the largest for any Messier object). This would give it a proper velocity of at least 1200 km/sec in a direction away from us. An inter-galactic boy racer if ever there was one.

However, M99 is not alone. The nearby M98 has a radial velocity of 195 km/sec (a blue shift) and therefore has roughly the same proper velocity as M99, but this one is moving towards us. So it is also possible to consider that these two might have crossed swords themselves, and therefore to imagine, somewhat romantically, that M99’s third spiral arm is the cosmic equivalent of a shattering lance belonging to one of two giant inter-galactic jousting knights.

A spiral Galaxy in Coma Berenices with a small nucleus and looslely wound arms (type Sc). Unlike M99, M100 rotates in a counter-clockwise direction. Deep photographs of M100 reveal that it is much larger than it appears in conventional photographs, with a significant part of its mass lying in the faint outer regions, too faint to be detected by conventional images.

The Hubble Space Telescope has imaged M100 extensively, and has discovered many Cepheid variable stars. Cephids (named after the proto-type star Delta Cephei) are yellow supergiants in a fairly advanced stage of evolution, so that they have used up their hydrogen and helium and have become unstable, swelling and shrinking over a period of about 3 to 50 days. There is a known correlation between their period and their real luminosity, and by comparing their real luminosity to their apparent luminosity we can accurately estimate their distance. Take, for example, Delta Cephei itself: if we first obtain its period, which happens to be 5.366 days, and refer to the known relationship between period and luminosity, we know that its actual brightness is -2.9. We then take the median apparent magnitude of 4.65 to obtain a difference of 7.55 magnitudes. This in turn can be used to look up on a table the corresponding difference in light intensity, in this case 1,000 times. That is to say the star is about 1,000 times fainter than it would be if it was at the standard distance of 10 parsecs, or 32.6 light years away. The distance is therefore 32.6 multiplied by the square root of 1,000, which gives us a distance of 1,031 light years. In this way, the distance of M100 has been calculated to be 56 (+/- 6) million light years away.