Spring is prime galaxy hunting season, so your telescope’s tripod is rarely better placed than on these May nights.
Constellation Virgo, the furrow of Demeter, culminates 9 p.m. May 25 upon the imaginary north/south meridian. Looking due south with the naked eye, east of Constellation Leo, you may find yourself somewhat underwhelmed at first. Do not be fooled: vast Virgo is unimpeded by the Milky Way and frames unimaginable deep space. Moreover, this is home to the Virgo Supercluster composed of up to 2,000 galaxies, itself is a mere lobe of Laniakea, a web-like structure of more than 100,000 galaxies.
Most of these galaxies, notorious to resolve in the best of times due to distance, faintness and fuzziness, are beyond the reach of backyard telescopes. Still, many are accessible using even a 3-inch (60mm) telescope, especially if you know where to look and use averted vision. Faintest magnitude for these small scopes is around mag. 13. Be mindful of light pollution, because the sky’s background contrast is all-important. The objects’ altitude is a factor to consider because the light-scattering tendency of layered air masses increases closer to the horizon.
Imagine, as the ancient Greeks did, Demeter as a recumbent goddess of agriculture, head toward the west and feet to the east. Look due south, gaze up about 38 degrees, and then scan right to find magnitude 1.0 blue giant star Spica, the ear of wheat. Then, find Constellation Leo’s beta tail star Denebola to the southwest 55 degrees above the horizon. These stars serve as celestial navigation reference points for finding galaxies in this neighborhood.
Draw an imaginary line from Denebola to Spica. From Denebola, travel about one-quarter line’s length. Break off the line a few degrees toward zenith to find a concentration of galaxies ranging in brightness from magnitude 8 to as faint as your instrument can manage. Find M49, a magnitude 8.4 giant elliptical galaxy (shaped like a blob) which was the first member of Virgo to be discovered; NGC 4535, a beautiful mag. 9.73 barred spiral Lost Galaxy of Copeland; and NGC 4526, a mag. 10.16 lenticular galaxy (like a spiral but without the arms) with embedded dust lanes.
Off the west coast of Denebola is the semi-circled Bowl of Virgo, aptly named because it holds many deep-sky objects including M58, M59, M90 and several galactic elements of Markarian’s Chain including The Eyes. Concentrate your efforts here: in a tight field of view, you’ll find radio galaxy Messier 84; conspicuous M86; the Virgo Galaxy (M87), the largest galaxy in the Virgo Cluster; and the 10 trillion sun halo M60.
Although some individual galaxies are incredibly beautiful in their own right, e.g. M61, the Swelling Spiral Galaxy, it’s worth spending a few nights digging in here to find the oddballs and the overlooked. Focus directly on the Celestial Equator in the heart of Virgo to find dozens of sights unique in their own way.
The Virgo Supercluster is not confined to Virgo. Lobe and filamentous structures weave outside its borders, insinuating tens of thousands of galaxies into other constellations including nearby Constellation Canes Venatici, the hunting dogs (two different ones). Find alpha Cor Caroli about 80 degrees above the southern horizon; beta Asterion/Chara is a few degrees above and to the west.
The Whirlpool Galaxy (M51) appears as a fuzzy ball in small telescopes, but larger optics reveal more detail. Both magnitude 9.0 spiral galaxies, M63 is about 3 degrees northeast of star Cor Caroli, while M106 is on the northwest line from Chara to Phecda, the Big Dipper’s lower left star and the bear’s thigh.
Mythological, historical and astronomical dramedy unfold across the celestial stage around 11 p.m. directly overhead at zenith. An ill-starred Ursa Major, the greater sow bear recognizable by the Big Dipper, is hotly pursued by the easy-to-miss two stars of Canes Venatici, the little hunting dogs of Boötes, the bear-driving herdsman.
This lopsided portrayal of miniature Cor Caroli (mag. 2.85) and Asterion/Chara (mag. 4.2) yipping after the huge but terrified Great Bear has not always been the story. Canes Venatici, which culminates 9 p.m. May 20 upon the north/south meridian, is a relatively modern constellation. Thousands of years ago in the star catalog “Almagest,” compiled by Alexandria’s Greco-Egyptian polymath Ptolemy, these two stars were included within the greater bear’s constellation but were not part of her representative asterism.
Through a series of mistranslations from Greek to Arabic to Latin along with mistakes and inaccurate guesses compounding over centuries, the unimpressive stars’ representation morphed. They floated around the catalogs as a club, a staff with a hook and as “spearshaft-having dogs” until 1687 when Polish-Lithuanian astronomer Johannes Helvetius carved them out creating their own dubious constellation. He named the northern star Asterion and the southern star Chara.
Even now, the confusion continues. The southern star is named Cor Caroli (Charles’s heart) in the very much still-in-use Bayer’s catalog, while the northern star is now called both Asterion and Chara. Miraculously, Canes Venatici survived the International Astronomical Union’s 1930 convention that officially cementing 88 scientifically accepted constellations while lopping off dozens of perhaps far more deserving ones.
The thrill of galaxy hunting increases greatly proportionate to the size of telescope mirror’s circumference, because the more diffuse light that’s captured, the better. There are plenty of cheap, subpar optics on the market that ruin the experience entirely, so research potential equipment thoroughly. That said, Charles Messier, the astronomer whose 18th century M-catalog is still in use, recorded numerous observations, including many in Virgo, using a 100mm (~4”) telescope from the rooftop of the Hôtel de Cluny in downtown Paris, France.
Before closing up for the evening, be sure to check out the famed Sombrero Galaxy (M104) about 10 degrees due west of Spica, which is not a member of the cluster.
The moon is full 7:53 a.m. May 23 and is called the Full Flower Moon.
