Messier 84: Elliptical Galaxy in Virgo

M84 is one of the easiest ways into the Virgo Cluster. It sits right beside M86, and the two together mark the western end of Markarian's Chain, a curving line of galaxies that runs across the heart of the cluster.

What it is

M84 is a large elliptical galaxy, a smooth ball of mostly old stars with very little gas or dust left to make new ones. It lies about 60 million light-years away, and the part you can see through a telescope spans very roughly 90,000 light-years. It belongs to the dense core of the Virgo Cluster, the nearest big cluster of galaxies, which also holds M86, M87, M89 and M90.

M84 is a strong radio source, with two jets streaming out of its center. In 1997 the Hubble Space Telescope measured gas whirling around the core fast enough to require a supermassive black hole there. Two supernovae have been seen in it, in 1957 and 1991.

When to see it

M84 is a spring object. From about 40°N it is highest around midnight in early April and around 10 p.m. standard time (11 p.m. daylight time) in early May, when it climbs to roughly 63° above the southern horizon. It sits just north of the celestial equator, so it is also well placed from most of the Southern Hemisphere, where it appears in the northern sky in autumn evenings.

How to find it

Find Denebola, the 2nd-magnitude star at the tail of Leo, and Vindemiatrix (Epsilon Virginis), the 3rd-magnitude star about 18° to the east-southeast. M84 and M86 lie almost exactly at the midpoint of the line between them, about 9° from each star. With no bright star nearby, sweep slowly at low power. Once you have M84, M86 is about 17′ to the east, in the same field of view.

What you will see

In 10×50 binoculars under a dark sky, M84 and M86 show as two tiny, faint spots of haze; from the suburbs they are hard to pick out. A 70–100 mm telescope shows M84 as a small round glow with a brighter center, with M86 alongside. A 200 mm telescope or larger turns the field into a galaxy party: the pair, plus fainter galaxies to the east such as NGC 4435 and NGC 4438, called "the Eyes." Filters do not help with galaxies.

History

Charles Messier found M84 on March 18, 1781, the same night he logged several other Virgo galaxies. He saw it as a round nebula without stars. Hubble's 1997 measurements of its core later added it to the list of galaxies known to hold a giant black hole.