The next target,
Gamma (γ)
Virginis, called Porrima, is one of the most famous double stars in the sky. This binary has been the subject of much research, and astronomers have even written poems about it. Nineteenth-century Royal Navy Admiral William Henry Smyth in his Cycle of Celestial Objects devotes eight pages to this double star. Both components shine at magnitude 3.5 and the separation between them is 2.9".
Make a note to revisit Gamma Vir every year or two. The pair is widening and by 2030, the separation will increase to 3.9".
Next up, NGC 4731, is not a bright galaxy (magnitude 11.5) but it has several features I think you’ll find worth your observing time. It appears as a highly distorted S shape because it doesn’t travel through space alone. You’ll easily spot its brighter companion: Look only 0.8° to the northwest for magnitude 9.2 NGC 4697, an elliptical galaxy I describe on page 61. Gravitational interaction between these two has nearly destroyed NGC 4731’s spiral arms.
Through a 10-inch telescope, observe NGC 4731’s long, relatively bright central bar. If your observing site is dark, crank up the power past 200x and look at the wide, irregular spiral arms that originate from each side of the bar.
The western arm appears somewhat brighter. Tiny bright patches within both arms signal hotspots of star formation. Through a 20-inch or larger telescope, use a nebula filter to increase the contrast of those regions and the galaxy’s older stars.
If you want to show someone an edge-on galaxy, the next object on our list will do nicely. Barred spiral NGC 4762 glows at magnitude 10.3. More than four times as long as it is wide (9.1' by 2.2'), NGC 4762 appears as a white line through medium-sized telescopes.
You won’t see a central bulge through any size scope. All you will notice is that the core appears ever-so-slightly brighter than the arms.
Next up is NGC 4856, a magnitude 10.4 spiral that lies near Virgo’s western border with Corvus. Through an 8-inch telescope at 200x, you’ll see a disk with a small, bright central region. The galaxy stretches more than three times as long as it is wide (4.3' by 1.2') in a northeast-to-southwest orientation. For those of you using 14-inch or larger scopes, crank the power past 350x and look for a magnitude 13.1 foreground star just barely east of the core.
At magnitude 13.9, you might be inclined to skip the next target, planetary nebula IC 972, for less difficult fare. That’s fine if you’re viewing through a 4-inch scope, but if you have a 10-inch or larger instrument, have a look at the faint outer layers of this once Sun-like star. Because of its small size (43"), IC 972 has a reasonable surface brightness. Better known as Abell 37, this object appears uniformly illuminated with a sharp edge.