Binocular Universe: Into the Realm April 2016   Phil Harrington

Bridging the constellations Coma Berenices and Virgo stands the Wild West for binocular astronomers, where only the brave trod.  You may know it as the Coma-Virgo Realm of Galaxies.  The Coma-Virgo galaxy cluster is the core of the Coma-Virgo supercluster, which embraces members far and wide.  All of the galaxies within autumn’s Sculptor galaxy cluster, as well as our Milky Way as well as the rest of the Local Group of galaxies, are counted among the multitude.

Nowhere else in the sky are galaxies so tightly packed together over such an expansive stretch of sky as the Realm of Galaxies.  There are 16 Messier objects within the Realm, as well as scores of other galaxies that are listed in the New General Catalog (NGC).  All told, an estimated upwards of 2,000 separate galactic systems call this home.

Above: Spring star map from Star Watch by Phil Harrington. Click the chart to open a printable PDF version in a new window.

Above: Finder chart for this month's Binocular Universe. Chart adapted from from Star Watch by Phil Harrington. Click the chart to open a printable PDF version in a new window.

Most amateurs consider this to be telescope territory. But we know better! It is indeed possible to see all of the Messier galaxies in the Realm through 50-mm binoculars.

But to be successful, your binoculars should really be mounted on some sort of tripod or other support.  This advice includes image-stabilized binoculars.  True, their technology will help calm jitters, but it is much easier to be able to go back and forth between mounted binoculars and the chart here chart without having to re-aim every time.

Another key to making your way through is a slow, measured approach.  Take your time going from one object to the next.  I have always found it easier to attack them en masse, staging my assault in two waves: one entering the Realm from the west, the other from the east.

Okay, let’s drive in. For the western attack, begin at the star Denebola (Beta Leonis) in the hind triangle of Leo the Lion.  From there, move one field (about 7 degrees) due east to a kite-shaped asterism of faint stars. We can use the kite to find our first four Messier galaxies.  Hopefully.

Stop #1 is at M98, just west of the kite. Giant binoculars running at 15x and more may reveal its cigar-shaped profile surrounding circular core.

Next, try for M99, just south of the kite's tail. It’s not significantly easier to see, glowing dimly at 10th magnitude. Can you spot it, as well?

If you can, then try your luck with an even more challenging target. M100 is rated a half magnitude brighter than M99, but that is misleading. Due to M100’s larger apparent diameter, its surface brightness is quite low. Both targets may require 70-mm or larger binoculars to confirm.

If those proved too tough, take heart. The fourth galaxy here, M85, should prove a little less demanding. Though only faintly visible through my 10x50 glasses on dark nights, it's relatively easy to catch in my 16x70 binoculars even from light-polluted suburban skies. Look for a brighter stellar nucleus surrounded by a fainter halo.

The eastern campaign begins from the star Vindemiatrix (Epsilon Virginis), and is a bit more involved with several twists and turns.  From Vindemiatrix, follow a path about one binocular field due west, where you will be greeted by a pair of suns, including 5th-magnitude Rho Virginis and a fainter 7th- magnitude star.

From Rho, follow a curve of stars to the south and west, to arrive at M49.  The brightest member of the Realm, M49 is seen as a nearly circular ball of fuzz, accented with a brighter core.  As mentioned below, M49 is one of the largest galaxies in the Realm, spanning an estimated 150,000 light years.

Next, looking through your binoculars, draw an imaginary line southwestward from Rho, past several stars and head southwest to a triangle of three suns.  About halfway along the triangle's western side, you'll find M61.  M61suffers from a low surface brightness, which causes many new observers to pass right by.  A slow, concentrated scan is your best chance at seeing its subtle glow.

Go back to Rho and then look just north to find M59 and M60.  M59, the western member of the team, is fairly obvious in all but the smallest backyard telescopes.  M60 is both larger and brighter than M59, and in fact, is one of the brightest galaxies in the Realm.  Look for a round sphere of distant starlight marked by an obvious stellar core. 

Next, M58 takes a good eye and lots of patience. Look for its soft glow west of M59 and M60. But don’t confuse it with M89 to its northwest. Both are faint, but should be individually discernible with patience.  M89 looks almost perfectly circular, but at only 10th magnitude, it’s a challenge through 50-mm binoculars.

M89 lies next to M90.  In photographs, M90 reminds me of a miniaturized Andromeda Galaxy.  Its spiral-arm halo is tilted almost due north-south, poised nearly edge-on to our line of sight.

Continue to arc toward the north-northeast to arrive at M91, a barred spiral. Careful examination with giant binoculars may show that the central core is actually oval, tilted northeast-southwest, lining up in the same the direction as the galaxy's bar.

Hop a little less than a degree to the east-southeast from M91 to arrive at M88.  M88, set just southeast of a 9th-magnitude field star, displays a bright nucleus that appears offset within its spiral-arm halo.   M88 is an Sbc spiral galaxy characterized by fairly loose arms.  Binoculars reveal a moderately bright core engulfed by the spiral arms' faint, oval glow.

Now, retrace your steps along the arc back to M89, then continue toward the west to M87.  Keep an eye out for M87's central core, which will look like a faint fuzzy "star" surrounded by a circular mist. In reality, this is a monstrous elliptical system perhaps 10 times more massive than our Milky Way. A luminous jet of material seen bursting from its core in photographs is powered by a supermassive black hole buried deep within. Both M49 and M87 are considered "super galaxies," two of the largest galaxies ever found.

We wrap up the Realm by heading east-northeast just a bit to M84 and M86, which lie right at the heart of the Realm.  Only a third of a degree separates them in our sky.  Each of these elliptical galaxies shows a round or slightly oval disk in binoculars. Tiny stellar cores are also detectable with 12x or more. At a casual glance, both of these 9th-magnitude galaxies look identical. But a closer look shows M84 to be a little smaller and a little brighter than its neighbor.

So, how many of these galaxies -- and more -- can you find through your binoculars?  Be sure to post your results in this article's discussion forum. 

And if you have suggestions for future targets, by all means post them there, as well. Till next month, remember that two eyes are better than one!