Nebulae in Sagittarius

22 – 23 July 2020, 23:00 – 1:00

Conditions: Breezy, partial cloud cover to begin with – clearing over the course of the session and then returning towards the end.

Seeing: Poor / average
Transparency: Average / poor

I know I’ve spent a lot of time exploring Sagittarius lately, but at the rate the neighbour’s trees are growing and the likelihood of local light pollution returning to its pre-lockdown levels, this might be the last best chance I get to study this object-rich part of the sky. With the nights growing longer again, the wonders of Cygnus and Cepheus will still be well-placed for the next two or three months; the same can’t be said for the southern Milky Way.

NGC 6440, globular cluster, Sagittarius
133x. Faint condensed blur in same field as NGC 6445, brightens with averted vision.

NGC 6445, planetary nebula, Sagittarius
133x (no filter) and 171x (OIII). Quite faint without the filter (one of the consequences of averted vision is that this nebula was easier to see when I was looking straight at 6440). With the filter in place, 6440 disappeared and 6445 became much more obvious. The higher magnification made the misshapen ring structure more apparent (it looked more like a buckled wheel than a box). Most prominent feature was a bright condensation on the northern rim.

M8, Lagoon Nebula, Sagittarius
171x + OIII filter. Obviously M8 loses a lot of its impact at this magnification, but the brightest part of the nebula is easier to study. Hourglass shape apparent, of which the southern component brighter. Smattering of embedded stars visible with averted vision.

M20, Trifid Nebula, Sagittarius
171x + OIII filter. M20 also loses some impact at higher magnification, but the central star system was easier to resolve (when the seeing allowed) as a line of three very close stars. Nebula and dark lanes best seen with averted vision.

M16, Eagle Nebula, Serpens
171x + OIII. Averted vision showed a dark patch at the centre of the nebula, but the contrast was still too low to make out any kind of shape or structure. Lower magnifications are better for this object.

M17, Swan Nebula, Sagittarius
171x + OIII. Nebula still very bright at 171x. This magnification doesn’t really add anything to this object although the dark lanes were 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.

NGC 6629, planetary nebula, Sagittarius
171x + OIII. Very small, bright little disc, north of M28. I may have seen the central star with averted vision, but it was tough to separate from the nebula.

I also looked for other Sagittarius planetaries 6537, 6567 and 6644 with this eyepiece/filter combination, but they eluded me on this occasion. Or to put it another way, nothing jumped out at me in the manner that 6445 and 6629 did.

M28, globular cluster, Sagittarius
133x. As per previous observations. Bright, condensed; grainy with averted vision.

M22, globular cluster, Sagittarius
133x. If this is my last look at Sagittarius for the year I had to finish with arguably its most spectacular object. Several dozen stars seen in direct vision. The low altitude can make this cluster look somewhat washed-out at first glance, but it's well worth investing the time to let the magnificent view build up on your retina like a developing photo.

As usual I closed the session with a look at Jupiter and Saturn. Jupiter was the stand-out tonight with the GRS on show and all four Galilean moons positioned on one side of the planet. However the seeing was too mushy to bother with an imaging run.

From the Lagoon to the Eagle (in OIII)

21 – 22 July 2020, 23:00 – 1:00

Conditions: Started mild, ended chilly (much like the previous night). Light breeze. Some light pollution spilling over from next door (I’m glad I didn’t leave those last three Messiers until tonight).

Seeing: Poor
Transparency: Average

I’d been hoping to revisit the various Sagittarius nebulae with the Astronomik OIII and tonight seemed like the perfect opportunity to use a filter. Observations at 92x unless otherwise stated.

NGC 6445, planetary nebula, Sagittarius
Conspicuous-sized ghostly disc on the western side of the constellation. Quite bright in OIII. Averted vision transformed the disc into a ring, with brighter segments to the north and south.

M8, Lagoon Nebula, Sagittarius
The nebulosity becomes even more expansive in the OIII filter, filling most of the fov of the Ethos (at the expense of the starlight, which is greatly subdued). The large rift dividing the cluster from the brightest part of the nebula now looks like a dark crescent surrounded by nebulosity. On previous occasions I’ve found it difficult to reconcile the telescopic view of M8 with the familiar one seen in images, but tonight it really did start to resemble a photo (minus the colour of course).

Another bright ISS pass (nearly overhead) at 23:20 – 23:25.

M20, Trifid Nebula, Sagittarius
The Trifid seemed distinctly larger and – while not particularly bright – stood out from the background sky much better in the OIII filter. The dark lanes showed well in averted vision. It took a little more effort than M8, but again, it did start to resemble a black-and-white photo (but without the reflection nebula component).

M17, Swan Nebula, Sagittarius
Very bright 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 but a swan. It almost appeared to be frozen in the act of gliding through space. The area immediately to the north (directly beneath the “body”) was 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 was mottled, including a dark band cutting across the neck, although I think these dark features are easier to see at 133x. Also noticed a little detached portion of nebulosity directly above the head.

M16, Eagle Nebula, Serpens
Not especially bright, even in OIII, but the bird-like shape was more apparent. The filter transformed the nebula into a broad, diffuse band of light which appeared to curl (like wings) around the cluster. averted vision showed a wedge of darkness cutting into the nebula from the eastern side, but it was ill-defined, certainly not as dramatic as the photographic appearance.

Subsequent observations at 171x (no filter).

NGC 6717 (Palomar 9), globular cluster, Sagittarius
Small, grainy glow just south of 5th magnitude Nu² Sgr – not hard to spot despite the glare from the star. Condensed with averted vision, which also revealed a second bright spot north-east of the core. An interesting object (the globular equivalent of NGC 404 in Andromeda).

Rounded off the session with a look at Jupiter and Saturn, followed by some imaging of the same. Variable seeing limited the quality of the results.

Completing the Messier Catalogue

20 – 21 July 2020, 23:30 – 2:00

Conditions: Mild to begin with, but got chillier. Very gentle breeze; light condensation towards the end of the session. Proper astronomical dark was back at last (for an hour at least).

Seeing: Average
Transparency: Good

Comet C/2020 F3 NEOWISE continues its progress over the north-western horizon. Becoming harder to see with the naked eye, but still a good sight in binoculars. Definitely fainter now, but the tail is longer.

All observations (apart from the planets) at 92x with the 13mm Ethos. The XT10 was propped on the improvised “Observing table + bricks” platform again – hopefully for the final time. For the last couple of sessions I’ve been using a magnetic 3 lb counterweight to help balance the scope when attaching the camera or heavy eyepieces like the Ethos to the focuser. I’m not sure it’s worth the price Orion charge for it, but it does the job (without marking the scope), so I can’t argue with that.

M8, Lagoon Nebula, Sagittarius
A quick look (sans filter). The Ethos is the best eyepiece for framing this object, showing the nebula, the cluster (NGC 6530) and 7 Sagittarii all in the same field of view.

NGC 6522, globular cluster, Sagittarius
Quite obvious in the Ethos, if faint. Small and condensed; averted vision revealed some faint stars on the outskirts of the cluster – possibly foreground stars.

NGC 6544, globular cluster, Sagittarius
Small, faint globular, south-east of M8; very condensed core with averted vision – almost star-like. Faint star west; three more east.

NGC 6553, globular cluster, Sagittarius
Large, extended globular, south-east of 6544 and M8; brighter towards centre, but not particularly condensed. Faint star just north-west of core.

NGC 6624, globular cluster, Sagittarius
As per previous observation: bright, condensed. A bit more prominent tonight.

M69, globular cluster, Sagittarius
More obvious tonight, but still faint. Quite condensed core with averted vision. Bright star NNW.

M70, globular cluster, Sagittarius
Faint, low surface brightness globular, but clearly visible tonight – though not as obvious as M69. Some sources list M70 as being smaller than M69, but to my eyes it seemed a little larger, perhaps because M69 is more concentrated. Bright field star to west. The cluster appeared condensed with averted vision, which also revealed a faint star north of the core, plus a suggestion of fainter stars east of the core.

At 00:15 there was a very bright ISS pass, almost directly overhead.

M22, globular cluster, Sagittarius
A refreshing change after all those faint globulars: large, rich and expansive – brimming with stars; really fills out with averted vision. I imagine seeing this from the UK must be a bit like seeing Omega Centauri from the southern US states.

M11, open cluster, Scutum
Amazing as always. The lucida is on the eastern corner of cluster. Finely resolved in the Ethos – gives a really crisp view.

M26, open cluster, Scutum
Small kite-shaped cluster with a curving chain of stars to the north and a fainter spray of stars to the east. Central asterism curiously empty.

🍾 M55, globular cluster, Sagittarius 🍾
Very large, low surface brightness globular – like a ghost of M22. No wonder I struggled to see it at the higher magnification last time out, but tonight there was no mistaking it with the Ethos. With time and averted vision, a faint sprinkling of stars began to appear, the brightest one located south-east of the core (not sure if this was a true member or a foreground star). It’s taken a while, but I’ve now seen every single Messier object – all of them from my garden, and all but one of them with the XT10. A modest achievement perhaps, but one I didn’t think was possible until a few months ago (when I saw M83).

I rounded off the session by upping the magnification to 171x and taking a look at a couple of planets, beginning with Saturn at opposition. The view was a little hazy because of the increasing condensation, but the enhanced brightness of the rings immediately stood out (they were so bright they made the closer moons a little harder to see than usual). The Cassini Division was showing well and there was even some brightness variation across the rings (which I’ve only previously seen in photos). The colour contrast between the dusky, slightly tan planet and the very pale blue-tinged rings was also noticeable. The effect was subtle and came and went with the seeing, but at times it really did look like the Saturn I’ve seen in photos.

Mars is gradually increasing in size and phase. Some vague dark markings were visible and the polar cap was bright, but the seeing in this part of the sky is still quite poor. Hoping a dust storm doesn’t obscure the surface at opposition like it did in 2018.

Nature note:
A noisy wader (possibly an oystercatcher) flying around for much of the night provided an atmospheric soundtrack to the session. Also, a frog jumped on my foot (I heard it approaching, so I wasn’t taken completely by surprise).

Exploring Sagittarius

17 - 18 July 2020, 23:30 – 1:45

Conditions: Muggy, mild, breezy. Patchy cloud. Light condensation increasing over the duration of the session.

Seeing: Poor
Transparency: Average / poor

Comet C/2020 F3 NEOWISE has moved further into the evening sky, appearing a little faded since the previous weekend but still a relatively easy naked-eye object. Binocular view still good: the tail seemed longer, perhaps because I was seeing it against a darker sky.

Eyepieces used tonight were the 9mm Nagler (133x) and the 7mm DeLite (171x). The XT10 was balanced on the improvised “Observing table + bricks” platform again.

NGC 6522, globular cluster, Sagittarius
133x. Small, condensed fuzz with star-like core. Near Gamma Sgr. The low altitude and poor seeing made it hard to be certain but the core seemed to double with averted vision, possibly due to a foreground star nearby. Couldn’t confirm neighbouring globular NGC 6528.

M69, globular cluster, Sagittarius
133x. Definitely saw it tonight – visible as a soft round blur just south of an 8th magnitude star (which helps a lot when tracking it down). A little condensed with averted vision. In the brief window of time I had to look at it I was able to make out 2 or 3 speckles of individual starlight – possibly foreground stars, but overall this globular remained very faint.

M70 is harder to locate because there is no comparative star nearby. Again, I’m not confident I saw it this time – confirmation will have to wait for a better night. Likewise, M55 was right on the threshold of visibility; I think I glimpsed it with averted vision along with a few speckles of starlight, but I want to see it again to be sure.

I moved the XT10 to a less precarious spot and looked at Jupiter and Saturn at 171x. Both planets were visibly “rippling” with the seeing, so I abandoned my plan to do some imaging and returned to a couple of deep-sky objects.

M75, globular cluster, Sagittarius
Currently not far away from Saturn in the sky and quite obvious at 171x (though I suppose most DSOs would seem obvious after struggling with the previous three). Small, bright, condensed – swells in size with averted vision. Hint of graininess, but no stars popping out. Suggestion of dark area on the eastern side.

NGC 6818, “Little Gem Nebula”, planetary nebula, Sagittarius
171x. Small, fairly bright green-grey disc, slightly oval. Shows well at this magnification. Suggestion of darker centre. Oddly, with averted vision it seemed more blue-grey than green-grey.

From the Lagoon to the Eagle

24 – 25 June 2020, 23:30 – 3:00

Conditions: Warm and breezy.

Seeing: Terrible
Transparency: Poor

Once again I set up two telescopes in the garden, but this time, instead of the TV-60 on the Super Polaris mount, I brought my old Vixen 4-inch refractor (below) out of retirement to see if the extra aperture would help me catch those last remaining Messier globulars. As it turned out, the sky transparency was too poor to spot them (if only I’d had this idea before the previous session). The XT10 was, once again, coupled with the 13mm Ethos.

I warmed up with a look at M13 and M11 in both scopes. I didn’t take notes as the conditions were too poor to make a fair comparison. Neither cluster was at its best tonight. That was followed by a dive back into the wonders of Sagittarius.

M23, open cluster, Sagittarius
92x. As noted before: a rich cluster of uniformly bright stars, but better-framed at this lower magnification. The stars seemed to form the outline of a flattened starfish or a magic lantern (although the fluctuating seeing may have been a factor in my interpretation). Bright star north of the cluster.

M8, Lagoon Nebula, Sagittarius
92x. M8 is so large that even the Ethos barely contains it, but it’s a wonderfully complex region at this magnification. Despite the less than ideal conditions, even the unfiltered view clearly showed the key components: the bright star cluster NGC 6530, the nebulosity to the west, and the wide dark lane (the “laguna”) dividing the two. A little further west, the bright star 7 Sgr completes the line up, giving M8 the extended shape which is so distinctive in finders and binoculars. The nebulosity filled out considerably with the addition of the Ultrablock filter, revealing another patch to the south extending along the other side of the laguna into NGC 6530, and a large fainter band of nebulosity to the north, all separated by dark lanes. The brightest segment (the one clearly visible without a filter) was transformed into a dense mottled patch of nebulosity. It’s a shame with it being so low in the sky that I don’t get more time to savour M8, but any view is better than no view at all.

M20, Trifid 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.

M6 and M7, open clusters, Scorpius
42x (SP-102 + 24mm Panoptic, giving a 1.5-degree field)
Both clusters were well-framed in the Vixen and showed a respectable number of stars, although they suffered from the haze and poor seeing. The butterfly shape of M6 was more apparent tonight, and the ring of stars surrounding the core region of M7 gave it a stretched-out appearance, like a spider’s web slowly being pulled apart.

Back to the XT10, and back to the nebulae:

M17, Omega/Swan Nebula, Sagittarius
92x + Ultrablock filter. As noted before: very bright, distinctive swan-shaped nebula. Mottled with averted vision but a lot of the fine detail I’ve seen previously was lost to the deteriorating seeing.

M16, Eagle Nebula, Serpens
92x + Ultrablock filter. Loose, sinuous cluster (NGC 6611) embedded in a faint haze, the size of which increased dramatically with averted vision. The most prominent section was 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 tapered off smoothly into the background sky and it was hard to make out any dark features or other structure.

M24, star-cloud, Sagittarius
92x. As noted last time out, a staggeringly rich star-field, “squared-off” by surrounding dark nebulae. A little smeared-out by the poor seeing, but still a sight to behold.

M25, open cluster, Sagittarius
92x. As pre previous observation: rich, large cluster, well-framed in the Ethos. D-shaped asterism at centre.

I also revisited M22 but, unsurprisingly, the poor sky conditions had turned it into a shadow of the magnificent cluster I saw last time out. Jupiter and Saturn were also afflicted by the mushy seeing.

As noted earlier, I failed to spot M69 and M70 with the Vixen, but M54 was just about visible at 42x.

Nature note:
I had to be careful where I was treading tonight because there were lots of froglets (plus several adult frogs) on the move, as well as all the usual snails and slugs.