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).