Open Clusters in Canis Major and Puppis

6 March 2021, 19:30 – 21:30

Seeing: Average

Transparency: Poor / average

A bitingly cold, breezy evening with plenty of large low clouds scudding from northeast to southwest. Some fireworks were going off in the local park while I was setting up; I assume they were for someone’s birthday or anniversary, as I can’t think of anything else (on a national level) worth celebrating at the moment.

As I was uncertain how much observing time the clouds were going to allow me, I stuck to one eyepiece (the 13mm Ethos at 92x) for the entire session. The conditions weren’t great and my eyes weren’t properly “tuned in” for viewing faint objects (like any skill, averted vision can get rusty if you haven’t used it for a while), but it was a relief to do some actual deep sky observing again after what seemed like an eternity. On another plus note, I tightened up the azimuth bolt and the milk washer trick has worked – the scope turned like a dream, with no stiction. I’m not sure how long it will stay like that, but it’s a cheap and relatively easy fix.

After warming up with a look at the Orion Nebula (because it would feel like a crime not to, when you’ve got an Ethos in your scope), it was over to the other side of the sky to mop up some galaxies in Camelopardalis and Ursa Major.

NGC 2655, galaxy, Camelopardalis

Large round blur with a bright core surrounding a stellar nucleus. The PSA plots another galaxy (NGC 2715) nearby, but I wasn’t able to see it on this occasion.

More clouds obscured the view while I was looking for NGC 2366, so I was forced to relocate back to the far southern reaches of the sky, and an old favourite:

NGC 2362, Tau Canis Majoris cluster (Caldwell 64), Canis Major

Stunning as always; there’s no other cluster quite like it. Not much I can add to previous descriptions, but tonight the seeing steadied enough to show two faint companions east of Tau.

h3945, double star, Canis Major

Beautiful golden primary and duck-egg blue secondary. Another highlight I couldn't resist coming back to.

NGC 2367, open cluster, Canis Major

Small, triangular cluster with about a dozen stars visible.

NGC 2384, open cluster, Canis Major

Small, sparse cluster with meandering trail of stars to the northeast.

NGC 2421, open cluster, Puppis

Rich spray of faint stars. Averted vision suggests underlying haze on the brink of resolving into even more stars.

Another cloud pushed me south again, and while in the area I noticed an interesting asterism south of 3 Puppis which looked like a loose open cluster, but wasn’t marked as such in the atlas. Also, to the north, a beautiful bright double star (k Puppis) comprised of twin white stars. (If h3945 is the winter Albireo, this looked like the winter Gamma Arietis).

M93, open cluster, Puppis

Lovely, rich cluster which looked a bit like a butterfly tonight (brighter stars in the western wing). Two prominent red giant stars on the southern edge of the cluster.

NGC 2482, open cluster, Puppis

Sprinkling of medium-bright to faint stars; larger and looser than M93. Appeared to be an isolated knot of stars of the eastern side of the cluster. My initial impression was favourable, but this cluster seemed to get less impressive the longer I looked at it. (With hindsight, it’s possible there could have been a very thin layer of cloud passing slowly across it.)

NGC 2489, open cluster, Puppis

Small haze sprinkled with faint stars. Just north of three distinctive field stars. I didn’t spot it straightaway, but it is somewhat low in the sky.

With another cloud starting to creep across, I pushed north again and (thanks to the silky-smooth azimuth motion) I swung the scope back and forth between M46 and M47, comparing the two clusters. Photographs tend to bloat out the stars and perhaps make them seem more alike than they really are, but visually the difference between the very bright stars of M47 and the fainter but more homogenous stars of M46 was striking. Planetary nebula NGC 2438 on the northern edge of M46 was not quite as prominent tonight as previous viewings, but still obvious.

More clouds pushed me out of this part of the sky, so I resumed the galaxy hunt.

NGC 3198, galaxy, Ursa Major

Faint streak of light, brighter towards the centre with averted vision. Field star off the northwest edge.

Yet another cloud pushed me south to look for NGC 3432 in Leo Minor, but I couldn’t see anything on this occasion. At this point I realised I was fighting a losing battle (with the cold as well as the clouds), so I finished up with quick visits to NGC 2903, the Leo Triplet, and M81/M82 (including NGC 3077 and NGC 2976). None of them were looking anywhere near their best, so I called it a night.

Nature note:

The garden was quiet tonight; the frogs appear to have concluded their “business”, leaving one third of the pond full of frogspawn.