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Unexpected Coma Session: Orion/Helmerichs 300: 18/19th May 2022


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In a run of grey, windy or excessively Moonlit weather recently an unexpected gap in forecast appeared, suggesting Wednesday night (18th May) might be clear. It was! Dark enough to start collimating by about 10:20 pm, Moonrise wasn’t due until 1am. I find the time of Full Moon counter-intuitive. You imagine that being a full Moon, you won’t get dark nights for ages yet. A full Moon means that as soon as the Sun sets, the Moon rises, being diametrically on the opposite side of Earth from where you’re standing. So what that means is that the next night, the Moon won’t rise until approximately an hour after sunset, and each day a further nearly-hour. So, at just 2-3 days after full Moon, I found myself with nearly 3 hours of full darkness to play with. That suddenness of dark nights after full Moon always surprises me.

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Anyway, it was still a bit breezy from the South West so I set up on my more sheltered North-facing patio. Scope of choice tonight was my 300mm Orion-Helmerichs newt on AZ-EQ6 controlled by Nexus DSC. A quick collimation and alignment on Polaris and Arcturus. My novelty feature this night was First Light for my freshly centre-spotted 300mm mirror (Orion), which had been originally about 1mm off-centre, juuuust too much for my OCD to tolerate. I made up a triangular centre-spot and set it up so the apexes point directly to the collimation knobs. It allows me to predict which direction the Barlowed-return-shadow will travel.

Not having had much notice of the clear spell, and my perma-list of target objects being once again well out of date (I really need to create lists in advance), I cobbled together a short list, all in more or less the same area: the environs of Coma Berenices, mainly a mixture of galaxies and globulars. I did have one double on the list, WZ Cas (gleaned from, I think, @Nik271). Seeing was not bad except for some above-building regions, but transparency was not perfect: there was a sheen of high thin cloud, and a few instances where a thicker band moved in and luckily out again. Sky darkness started off at SQM-L 15.0 at 10:20 pm, where I could just barely discern Polaris, reached 21.65 just before 1 am, and when I packed up just after 1:30 am it was back down to 20.95 and sinking fast with the 89% Moon starting to rise. And, once again amazingly, no dew!

Mostly I used my Ethos 13, giving me 141x and a 0.7 degree field. I’d occasionally move up to the Delos 10 for 183x and did a bit of star-testing with the Delos 3.5 at a crazy 522x.

Anyway, the observing. I initially checked conditions on Epsilon Lyrae, the Double-Double, which was superb as it should be in a 300mm.

First on my list was a Coma galaxy, NGC 4872. At 11.7 mag, it’s one of the brighter members, or shall we say less-dim, of the Coma Supercluster. Certainly there was a galaxy fuzz-patch, and another slightly brighter one further East of it (below-left through the eyepiece), which would have been NGC 4889 (mag 11.4). There are dozens and dozens of others packed into that region, but I’ll need a bigger scope to see them in due course. It’ll be a treat when I do, Sky-Safari makes the field look like a globular of galaxies!

Next on my list was another Coma galaxy, NGC 4725. This was mag 10.0, much brighter, and so it was through the eyepiece. It’s more or less face on, with a bright core and a definite spiral structure, nicely symmetrical and clearly so with averted vision through the eyepiece. Lovely. Wikipedia’s photo of it is worth a visit, and I definitely “got” that shape.

Now I went to M64, assuming from memory it was a bright featureless elliptical, so I found it, took it in, moved on quickly. But on investigation it’s called the Black Eye Galaxy, and has interesting features that I might possibly have been able to discern had I spent more time on it. Dammit, next time.

My first globular of the evening was not in Coma but not far away, M13 in Hercules. Oh my God. I’d had a recent superb view through my 200mm newt, but this was a view apart. So big and so bright. I’ve observed M13 many many times obviously, and have seen the Propeller before but fleetingly. Tonight the Propeller was obvious and prominent. I spent a reasonable length of time at M13, returning to it a couple of times too. Never tiring.

Another glob, this time in Coma, M53. A third of the size of M13 and less bright, but still well resolved. I tried upping the magnification from 141x to 183x, but it became less satisfying, a little too dim. There’s another glob nearby, NGC 5053, which for some reason I couldn’t find. Perhaps it’s too loose, more like an OC, so I gave up. Certainly I think I should have been able to see it in this scope, but another time.

I chose M3 next, another large bright globular, not dissimilar to M13. I tried to study it and make out some features but by now patches of cloud were intruding, and from time to time it would disappear entirely!

I abandoned the Coma area and turned completely around to look at WZ Cas, a widely-spaced double in Cassiopeia, a random entrant to my list, but my goodness what beautiful colours! Deep red and bright blue, entrancing. No doubting where they were in the star field once you’re there! I finished off with Albireo and that was that. Cloud was now almost everywhere.

An entirely unexpected dark few hours and a few new objects. I used Charles Bracken’s “Astrophotography Sky Atlas” to select my list. It has just the right layout and scale for me to pick a page and choose targets. It doesn’t have any doubles, but for PNs, Galaxies and Clusters (and nebulae obviously) it’s very good. Thanks to @PeterW for introducing me to that.

Cheers, Magnus

Edited by Captain Scarlet
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G' Day Magnus, I'm glad you got a few hours of observing! The weather situation down here is similar to yours, days of clouds and rain. Very nice reading your report and wishing you clear skies!

Joe

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Just looked at more information about NGC 5053, a glob near M53. Now I understand why I couldn't find it; it's dimmer (mag 9.6) and spread across a larger area than NGC 2419 aka The Galactic Wanderer at mag 9.06. I have observed NGC 2419 through this scope, but it was extremely faint. With the non-perfect transparency of the other night no wonder I couldn't see NGC 5053. A challenge for the future.

Magnus

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32 minutes ago, PeterW said:

Are those streetlights in the background of your picture… i thought you lived in a very dark area?!

Peter

Yes they are streetlights, but about 6km away as the crow flies. They’re quite useful actually as the rightmost one is precisely due North from the house. There are streetlights in nearby Baltimore too, about 2km away, but I still get 22.0 sqm values at zenith around Easter. The odd lights here and there seem to make little difference, it’s whole city-fulls that seem to do the damage

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