M11 (NGC 6705), Wild Duck Cluster, open cluster, Scutum
50x, 92x and 133x: A wonderfully rich open cluster, one of the very best in the sky. Extremely rich, compact fan-shaped cluster at 50x. Finely resolved in the Ethos at 92x, giving a really crisp view; too many stars to count. Increasing to 133x shows the stars arranged in roughly half a dozen clumps separated by dark lanes – giving it the appearance of a “fractured” globular cluster. Bright 8th magnitude lucida on eastern apex, surrounded by a somewhat squared-off dense mass of stars. After all these years it still boggles me that I don’t have to travel any further than my back garden to see something as breathtakingly beautiful as this cluster.
M12 (NGC 6218), globular cluster, Ophiuchus
133x: Unusual, spidery cluster with a pear-shaped core and two long straight “arms” of stars forming a flattened “X” shape. Also a seemingly detached clump of stars to the west and a bright (foreground?) star southeast of the core, reminiscent of the one in M5. A straggly cluster, quite well resolved, with lots of intriguing detail. Easily visible in binoculars and finder.
M13 (NGC 6205), Great Hercules Cluster, globular cluster, Hercules
The only globular I could reasonably “resolve” with the 4-inch scope, but even that took some effort (partly because of the smaller exit pupil at 111x and above). The XT10 at 133x resolves pinpoint stars (in direct and averted vision) right across the face of the cluster, giving an impressive sense of scale and distance. A large, sprawling cluster compared to the likes of M5 and M92; not as condensed, with chains of stars curving out from the centre like wings. Dark Y-shaped propeller feature adjacent to the core, but you have to “get your eye in” to see it. No overall colour to the cluster that I can see.
The Ethos (at 92x) gives an aesthetically more pleasing view of M13, but it’s not quite as easy to resolve at 92x as it is at 133x. The Ethos fov is also large enough to fit in the two 7th magnitude stars either side of the cluster. When you see it in such a wide field that the field stop effectively disappears from view, it’s like being out there in space with it.
The Ethos also showed a feature I hadn’t noticed at other magnifications: two lines of stars running through M13 (parallel to the two 7th magnitude stars flanking the cluster). One running straight through the centre, and the other slightly offset to the southeast, adjacent to one of the arms of the propeller feature (adding to the contrast effect).
At 171x, M13 looks like a sprawling sea monster compared to M5, with good resolution across the face of the cluster.
I’ve also viewed M13 at 428x (7mm DeLite + 2.5x Powermate). At this magnification it looks less like a sea monster and more like a hanging basket brimming over with unruly bright flowers; the entire field of view clotted with ancient starlight.
See also:
NGC 6207 is visible nearby as a small, lens-shaped galaxy with a foreground star masquerading as a stellar nucleus. Not immediately conspicuous, but fairly obvious once you know where to look for it.
M14 (NGC 6402), globular cluster, Ophiuchus
133x: Large, reasonably bright globular – grainy and condensed. A few stars on the outskirts resolved with averted vision – most prominent of these are two on the WSW side of the cluster (part of a possible chain of four or more stars leading away from the core). I understand this cluster’s appearance is somewhat compromised by interstellar absorption from dust in the Milky Way.
M15 (NGC 7078), globular cluster, Pegasus
133x: Bright globular. Well resolved most of the way to the core, which is very condensed – more so than other globular clusters I’ve looked at. Nearby field stars really help frame this object, giving it a 3D appearance. Looks impressive at 240x too with pleasing contrast and lots of faint stars resolved. Member stars brighter than those of M2 (more stars visible in direct vision). Long, loose “tail” of stars to north. Bright, dense core.
M16 (NGC 6611), Eagle Nebula, emission nebula with cluster, Serpens
92x + Ultrablock filter: Loose, sinuous cluster (NGC 6611) embedded in a faint haze, the size of which increases dramatically with averted vision. The most prominent section is a large band of nebulosity south of the cluster extending SW to NE, filling a large part of the field of view. The edges of the nebula taper off smoothly into the background sky; hard to make out any dark features or other structure.
Even in the OIII filter the nebula is not especially bright (particularly compared to nearby M17), but the bird-like shape is more apparent. The filter transforms the nebula into a broad, diffuse band of light which appears to curl (like wings) around the cluster. Averted vision shows a wedge of darkness cutting into the nebula from the eastern side, but it’s ill-defined, certainly not as dramatic as the photographic appearance.
171x + OIII filter: Averted vision shows a dark patch at the centre of the nebula, but the contrast is still too low to make out any kind of shape or structure. Lower magnifications are better for this object.
M17 (NGC 6618), Omega/Swan Nebula, emission nebula, Sagittarius
133x: Very bright both with and without the Ultrablock filter (although the filter really helps improve the contrast in this light-polluted part of the sky). An extended bar of nebulosity with the brightest part forming the characteristic “2” or swan shape around a conspicuous dark patch. The main bar takes on an impressively mottled structure with the filter in place.
92x + OIII: The nebula becomes even brighter in the OIII filter; the elongated swan shape is so distinctive that once you’ve seen it a few times it’s hard to see anything else. It almost appears to be frozen in the act of gliding through space. The area immediately to the north (directly beneath the “body”) is very dark by contrast, as if the swan is riding on black ice or on the surface of an impenetrably dark lake. The nebula itself is mottled, including a dark band cutting across the neck, although I think these dark features are easier to see at 133x. A little detached portion of nebulosity is also visible directly above the head (south of the main nebula).
The nebula remains bright at 171x (plus OIII filter). This magnification doesn’t really add anything to this object although the dark lanes are a little easier to see, giving it a segmented appearance. The body section does appear remarkably straight, like it’s been “dragged” across the sky with a paintbrush.
M18 (NGC 6613), open cluster, Sagittarius
92x: Bright little cluster south of M17; not particularly rich, but the brightest stars seem to form the shape of a pointy toadstool, or a partially opened umbrella.
M19 (NGC 6273), globular cluster, Ophiuchus
92x and 133x: Large, grainy globular, somewhat condensed. Speckled appearance with averted vision. One star resolved north of the core, another one east of the core. Pretty good considering its low altitude (about the same declination as Antares).
See also, two other globular clusters nearby:
NGC 6284, 92x: Small, condensed blur, a little north of M19. Swells in size with averted vision. Faint star east of core.
NGC 6293, 92x: Another small, condensed blur. No resolution, but the core seems particularly bright. East of M19.
M20 (NGC 6514), Trifid Nebula, emission and reflection nebula, Sagittarius
92x + Ultrablock filter: Considerably smaller and fainter than M8, but shows well with averted vision. Nebulosity split by three dark lanes converging on a tight double star. The OIII filter makes the Trifid seem larger and – while never particularly bright – it does stand out from the background sky much better. The dark lanes show well in averted vision. It takes a little more effort than M8, but eventually it starts to resemble a black-and-white photo (minus the reflection nebula component to the north).
171x + OIII filter: M20 loses some impact at this higher magnification, but the central star system (HN 40) is easier to resolve (when the seeing allows) as a line of three very close stars. Nebula and dark lanes best seen with averted vision.
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