NGC 6864 (M75)

In the far eastern reaches of Sagittarius, near the borders of Capricornus and Aquila, lies Messier 75—a globular cluster that often gets overlooked in favor of its flashy summer neighbors. Discovered by Pierre Méchain in 1780, M75 (NGC 6864) sits at a daunting distance of roughly 67,500 light-years from Earth and well beyond the Galactic Center. Through a pair of 10x50 binoculars on a clear, dark night, you’ll spot it as a tiny, fuzzy knot of light, easily mistaken for a magnitude-8.5 out-of-focus star. It sits anchored just a couple of degrees southwest of the 5th-magnitude star 62 Sagittarii, serving as a quiet reminder of just how vast our Milky Way’s halo truly is.

Switching to a small telescope, such as a 4-inch refractor, begins to reveal the cluster’s unusual personality. M75 is classed as a Shapley-Sawyer Class I globular—the most highly concentrated category on the scale—meaning its core is exceptionally dense. At 100x magnification, the eyepiece presents a brilliant, almost stellar core surrounded by a soft, misty veil of light. While open clusters tend to give up their individual stars to modest glass, M75 keeps its secrets guarded; even at higher powers, the bright center refuses to resolve into granules, looking more like an unblinking cosmic eye staring back through the dark.

To truly crack open this dense vault of ancient suns, you’ll need a 10- or 12-inch telescope paired with high magnification on a night of steady seeing. At 200x and above, the tight nucleus glints with intensity, and the outer halo finally begins to reveal faint, sparkling resolution along its borders. Subtle extensions and tiny sprays of pinpoint stars flicker in and out of view with averted vision, contrasting beautifully against the faint field stars of the autumn sky. It takes patience to appreciate M75, but for the observer willing to star-hop out to the fringes of Sagittarius, this compact power-house offers a delightful reward.

NGC 6857

When scanning the star-rich fields of northern Cygnus—just a jump away from the familiar outlines of the Swan’s wing—we encounter a compact, captivating gem that often slips under the radar of casual stargazers. Discovered by William Herschel in September 1784, NGC 6857 is an active emission nebula and star-forming region nestled roughly 22,000 light-years away in the Perseus Arm of our galaxy. Herschel’s son John later cataloged it as a tiny cluster of faint stars "so small as almost to look nebulous," a mistake understandable given its tight, round appearance through small apertures. Though it easily impersonates a planetary nebula in an eyepiece, modern astrophysics reveals it as a lively HII region harboring ultra-compact pockets of newly forming stars. 

Center NGC 6857 in a 4- to 6-inch refractor at moderate magnification, and you will spot a tiny, soft knot of grey light anchored by an 11th-magnitude stellar point. At magnitude 11.4 and spanning less than one arcminute, it demands patience and steady seeing to reveal its character. Pushing the magnification up past 150× in an 8- or 10-inch reflector transforms this modest smudge into a subtly fan-shaped glow. A bright condensation hugs the southern side near the primary ionizing star, while the glowing gas gently tapers off toward the north, teasing the dark-adapted eye with hints of internal structure. 

Filter performance on NGC 6857 offers an instructive lesson in visual contrast. Slipping a narrowband UHC or OIII filter into your eyepiece yields a dramatic transformation, brightening the nebulosity and sharply defining its curved perimeter against the dense background stars of the Milky Way. However, take time to return to unfiltered views; without the filter, you can appreciate the delicate interplay between the bright central knot and its embedded stellar engine. It is a delightfully challenging object, reminding us that some of the night sky's most rewardingly intricate treasures come wrapped in small packages.