Goodbye Nova Herculis 2021

13-14 June 2021, 23:40 – 00:50 (BST)

Seeing: Average

Transparency: Poor

Conditions: A mild night with a light breeze. Very slight layer of condensation on the telescope tube after an hour.

All of tonight’s observations were carried out at 92x with the 13mm Ethos.

Nova Herculis 2021 (aka V1674 Her)

I was eager to see if the nova had got any brighter in the last 24 hours, but instead I found it had faded considerably by a good two magnitudes. (It was at a similar brightness to the nearby 8.5m field star HD 175919.) I didn’t notice any colour to the nova last night, but tonight it had a slight orange hue. I’ll be interested to read the explanation for this rapidly evolving nova’s behaviour once the analysis is completed, but in the meantime see:

https://skyandtelescope.org/astronomy-news/bright-nova-hercules/

Obviously, I’m glad I made the effort to see this nova last night rather than leave it for a day. It’s quite something to see a star change its appearance so dramatically in such a short span of time.

As well as V1674 Her, I also revisited a few other targets from last night. As expected, 61 Cygni looked lovely in the Ethos: a pair of pale orange headlights suspended in a sea of stars.

Open clusters NGC 6755 and NGC 6756 just about fit in the same fov at 92x, but I need a darker sky to really do them justice at this magnification.

But NGC 6709 did look better tonight. The Ethos gave the cluster more room to “breathe” and the v-shape formed by the brightest stars was more prominent.

NGC 6738, open cluster, Aquila

Plotted in SA 2000. Large, sparse cluster with a meandering line of stars running through the centre. Not impressive; I can see why it was left out of the PSA. Some sources don’t even recognise it as a real cluster.

NGC 6940, open cluster, Vulpecula

A long overdue return visit to this underrated cluster (its status isn’t helped by its proximity to the Veil Nebula.) Large, rich cluster of uniformly bright stars – fits nicely in the Ethos fov. A prominent red star (VG (or FG?) Vulpeculae) near the centre and a bright, close double on the western side of the cluster.

NGC 6826, “Blinking Planetary”, Cygnus

In same field as 16 Cygni in the Ethos; it’s hard to stop your eye constantly flicking from one to the other. Pale blue-green disc with a bright central star.

I rounded off the session with a look at the famous black hole Cygnus X-1, or to be more precise, its visible-light companion HDE 226868. It’s not that hard to find if you’ve got a decent map (I used chart 119 from my old copy of Uranometria). It’s the southernmost of a pair of 9th magnitude stars in a rich star-field near Eta Cygni. Like Nova Herculis 2021, this is a view to savour while you contemplate its astrophysical significance. I may not be able to see the black hole, but more I stared at that little patch of sky, the more I felt like it was staring into me.

Also, I wasn’t aware of this at the time, but Cygnus X-1 is right next to the much-photographed Tulip Nebula (Sh2-101).

Hello Nova Herculis 2021

12-13 June 2021, 23:50 – 01:50 (BST)

Seeing: Poor

Transparency: Average / poor

Conditions: A breezy night with the occasional small patchy cloud passing by. Noticeably chillier than Thursday night. Also, some light condensation.

Nova Herculis 2021 (aka V1674 Her)

You wait ages for a nova to come along … and now another one appears, perfectly placed for summer viewing on the Hercules / Aquila border. I had the MSA (Millennium Star Atlas) bookmarked ready for this one (Volume III, chart 1222), but it turned out I didn’t need a detailed chart; the nova jumped straight out in the finder, blazing away at somewhere between magnitude 6.0 and 6.5. Through the eyepiece at 133x it appeared as an intense little point of light, dominating the surrounding star-field. Although there wasn’t much more to see, I spent a long time in the nova’s company. It’s fascinating (and a rare treat) to look at such an object and imagine the thermonuclear processes involved as a white dwarf leaches material from a companion star, culminating in an explosive eruption.

While in the area I also noticed an interesting grouping of four stars to the west: two 8th magnitude stars flanked by two fainter stars, all in a roughly east-west straight line.

NGC 6709, open cluster, Aquila

133x. Pretty cluster of moderately bright stars arranged in a rough zig-zag pattern. Fairly large and loose; as noted last year, the centre appeared somewhat empty of stars. Visible in the finder as a misty patch of light.

At around 1:10 I noticed a really bright flare from a satellite passing overhead (travelling south to north).

NGC 6755, open cluster, Aquila

133x and 171x. Faint spray of stars in a rough crescent shape, with a stream of fainter stars tailing off to the east. Brightest member on the western end of the cluster.

NGC 6756, open cluster, Aquila

Located about half a degree NNE of 6755 (plotted in the PSA but not SA 2000). 133x: An even fainter fuzzy patch, and also somewhat smaller than its neighbouring cluster. Faint stars popping out with averted vision. At 171x I could see a tight, elongated core of faint stars, surrounded by a broken almond-shape of brighter stars, like an eye. I imagine this cluster would look quite good under a properly dark sky.

Beta Lyrae, Lyra

133x. Bright white star with three companions forming a triangle around the primary.

Delta Cygni, double star, Cygnus

171x. Brilliant icy blue-white primary with a very close companion 2.4” to the south. (I’m glad I used the DeLite for this one.) Beautiful split between the two stars when the seeing allowed.

61 Cygni, double star, Cygnus

171x. Lovely pair of bright yellow-orange stars in a rich star-field (must revisit this one with the Ethos). The separation appears similar to Albireo, and (like Albireo) the split was just about visible in the 9x50 finder. Like Barnard’s Star, this pair is a relatively close neighbour to the sun at 11.4 light years.

As I’d started the session with a nova, it seemed appropriate to finish with one: a return visit to Nova Cassiopeia 2021, which appears to be holding steady at somewhere between 7th and 8th magnitude.

Hunting Barnard’s Star

10-11 June 2021, 23:50 – 01:40 (BST)

Seeing: Good

Transparency: Average (but only during the “dark” window from 00:30 to 01:30)

Conditions: Similar to the previous night, but with two significant differences: the condensation was back, and so were the mosquitoes...

A succession of late nights (not helped by some ambiguous clear-sky forecasts) were starting to catch up with me, so I spent much of the session just ambling along the Milky Way with the 13mm Ethos (at 92x). Without wishing to sound like a spokesman for Tele Vue, all my TV eyepieces are exceptional, but the Ethos is something else – and not just because of the extra-wide field. There’s a crispness to its image which – coupled with the immersive fov and the slightly longer eye relief (compared to the Naglers) – makes for a really special viewing experience.

The only downside is that I was so wrapped up in the view, I was a bit lax about taking notes (how do you even begin to describe a 100-degree afov of the Milky Way through Cygnus and Vulpecula?), but I did record the following observations:

NGC 6910, open cluster, Cygnus

Pretty y-shaped cluster with two bright stars at either end of the “y” (one of which has an orange hue). Fainter stars showing with averted vision.

M80, globular cluster, Scorpius

As per previous observations, but now I was catching glimpses of another, fainter star roughly due west of the cluster (at 90 degrees to the bright 8.5m field star).

Barnard’s Star, Ophiuchus

Found it at last – after some previous half-hearted attempts. At a distance of six light-years, this is the Sun’s fourth-closest neighbour (after the Alpha Centauri system) and the closest one visible from the northern hemisphere. You need a good finder chart to track it down and fortunately chart A1 in SA 2000 is up to the job. Visually of course there isn’t much to see other than a magnitude 9.5 star in a fairly rich field, but it’s certainly thought-provoking and worthy of contemplation. I expected its redness would make it stand out, but what little colour I could see was subtle: a very slight orange tinge.

I followed that with some enjoyable views of M11, M71 and M27 before relocating to Cepheus. I failed to spot galaxy NGC 6951, but reflection nebula NGC 7023 and the cluster/galaxy pairing of NGC 6939 and NGC 6946 were just about visible through the midsummer murk.

I tried to compensate for the deteriorating transparency by adding the OIII filter, squeezing in views of NGC 7000, NGC 6888 and the Veil Nebula before the end of the session.

From Cygnus to Aquila (via Lyra)

9-10 June 2021, 23:50 – 01:50 (BST)

Seeing: Good

Transparency: Average within 20-30 degrees of the zenith, poor everywhere else

Conditions: Yet another still night with the temperature steadily falling from a mild start. Smell of honeysuckle on the breeze. Earlier in the evening (at around 22:30) the signs looked promising for a noctilucent cloud display low in the north, but it fizzled out before it ever really got going.

I began with a return visit to Nova Cassiopeia 2021 / V1405 Cas (at 133x) which is still binocular-bright at somewhere around 7th magnitude. After fading from its dramatic May peak, it appears to be creeping back up in brightness again. 

That was followed by a look at summer favourite Albireo before plunging into the Milky Way again.

NGC 6834, OC, Cygnus

133x. A rich cluster arranged in clumps, with an overall shape resembling a wide upturned tree or a Jewish menorah. The latter description is perhaps more apt because the cluster’s brightest stars are aligned in a row where the candle-flames would be. Lots more faint stars pop out with averted vision, breaking up the shape a little. This is one I overlooked from the previous session, but now I’ve seen it I’m glad I made the effort to track it down.

SA 2000 lists a planetary nebula (NGC 6842) near here, but I couldn’t see it, so onto the next object.

M1-92 (Minkowski 92, aka the Footprint Nebula), PPN, Cygnus

My first protoplanetary nebula (not that I have many to choose from). Interestingly, both the PSA and SA 2000 use the regular square nebula symbol for this object. I had to increase the magnification to 240x (5mm Nagler) to find it and even then it was tiny, appearing as an elongated fuzz east of a field star. The nebula itself was fairly bright and did actually resemble a footprint (albeit a very, very small one), with the western component appearing larger and brighter than the other. I might revisit this one at 333x or 428x when it’s nearer the zenith (assuming I can find it again).

While in the area I also looked for Campbell’s Hydrogen Star (PK 64+5.1). I’m pretty sure I had it in the fov, but there was no obvious sign of anything red and/or nebulous. Again, I think this is one for 333x or higher.

I had planned to explore the Milky Way with the 13mm Ethos, but with the seeing actually reasonably stable for a change, I opted to stay at high power and revisit a few well-known (and a few not-so-well known) objects.

All four components of Epsilon Lyrae (the Double-Double) showed a good split at 240x. I could also see three fainter stars and one brighter star (east) between the two pairs. 

M57 (the Ring Nebula) also looked good at 240x, near its maximum elevation. Nothing new I can write about the nebula itself on this occasion, but I was able to see (with averted vision) a couple of very faint stars on the northern side of the ring (opposite the 13m and 14.1m stars noted previously). One of these is the combined light from a multiple star, but the other is listed as magnitude 14.7, the faintest (confirmed) star I’ve yet seen with the XT10.

M56, globular cluster, Lyra

240x. Loses its shape a little at this power, but lots of stars resolved across the face of the cluster, particularly with averted vision. Bright star leading.

NGC 6826, “the Blinking Planetary”, Cygnus

Impressive view at 240x; holds brightness well. Pale blue-green disc with a bright central star. No detail within the disc that I could see, though (as I later found out) I was looking for darker areas when perhaps I should have been looking for brighter ones.

NGC 6804, planetary nebula, Aquila

240x. Faint amorphous disc, with a star on the northern edge and a fainter one near the centre. No obvious sign of nearby NGC 6803 (it must be really small), but I didn’t spend a lot of time looking for it.

NGC 6760, globular cluster, Aquila

240x. Faint (for a globular) round glow which brightens towards the centre. Averted vision shows it to be mottled with some faint stars popping into view on the outskirts – are these actual members or foreground stars?

NGC 6781, planetary nebula, Aquila

240x. Large, faint disc – too large for 240x. A better view came at 171x with the OIII filter, giving the nebula a clumpy, punctured appearance –like a balloon that’s just started deflating.

And finally, before the sky became too bright:

M8, Lagoon Nebula, Sagittarius

171x + OII, 133x. A quick look through the neighbouring garden’s rapidly increasing foliage (I don’t think I’ll be seeing many of the treasures in Sagittarius this summer, unfortunately). The finder showed a line of bright stars embedded in nebulosity. 171x + the OIII filter showed the nebulosity intensifying to a tight core that looks like it’s been pinched and twisted into the distinctive hourglass shape. There was also a suggestion of second, narrower dark area west of the main “lagoon”. At 133x (minus filter), the open cluster NGC 6530 dominated the view, the stars arranged into an angular, unwinding spiral.

Nature note

My stargazing was accompanied by the sound of frogs moving through the garden again.

Along the Milky Way in Cygnus and Vulpecula

7-8 June 2021, 23:50 – 01:30 (BST)

Seeing: Poor

Transparency: Poor / average

Conditions: Mild (but cooling quickly), almost no wind. Some patchy high cirrus, but nothing like the forecasted amount.

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Note: The previous Saturday (5 June) I took the 7x50 binoculars out for what was supposed to be a quick look, though (as is often the case) I lost track of how long I actually spent scanning the Milky Way. The North America Nebula (NGC 7000) in Cygnus is just about visible with binoculars on a good night, though it’s hard to distinguish from the very rich star field. I’ve tried previously to see if I could spot it unmagnified by holding up one of the nebula filters to my eye, but without success. This time I experimented with holding the filter over one of the eyecups of the binoculars. The OIII filter dimmed the view too much, but the brightest parts of the nebula were clearly visible through the Ultrablock filter (even when I switched over to my right eye). As expected, I wasn't able to see the Veil Nebula or the nebulosity around Gamma Cygni using this method.

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Tonight I started out with another scan along the Milky Way, with the 24mm Panoptic (50x) plus the Ultrablock filter:

The North America Nebula (NGC 7000) was huge and obvious, but indistinct in shape.

The Veil Nebula was its usual ethereal, spooky self.

The Crescent Nebula (NGC 6888) was visible as a subtle arc of light (like the Veil, I think it responds better to the OIII filter, but it does seem very sensitive to viewing conditions).

M27 (the Dumbbell Nebula) was very bright and somewhat elongated.

NGC 6823, open cluster, Vulpecula

50x + Ultrablock filter. Small nest of stars overlaying a fine mist, but hard to tell if this is the nebulosity (NGC 6820) or just unresolved starlight. Switching to 133x (no filter) revealed a tight delta-shaped formation of four stars (including one red star) surrounded by a loose spray of 20+ stars. No nebulosity that I could see at this power. Note: according to Wikipedia, NGC 6820 is a reflection nebula and both it and the cluster are embedded in a much larger, fainter emission nebula, Sh 2-86 (SA 2000 plots this larger nebula, but labels it as 6820). A possible future astrophotography target. 

NGC 6830, open cluster, Vulpecula

133x. Loose formation of stars shaped like a fold-up chair. Doesn’t really jump out from the surrounding Milky Way.

Stock 1, open cluster, Vulpecula

133x. Very large and loose collection of bright blue-white stars (and one lone red star). Shows quite well in the finder. Too large for the main fov, but one or two close doubles in the cluster.

NGC 6800, open cluster, Vulpecula

133x. Another loose, large group of moderately bright stars. Unremarkable. One for smaller, wide-field scopes. Note: this is one of those rare examples of an object that’s plotted in the PSA but not in SA 2000.

NGC 6871, open cluster, Cygnus

133x. “Split” cluster in an incredibly rich star-field. Not sure where this cluster ends and the Milky Way begins, but the core area consists of a triangle of bright stars on the north side, two bright stars on the southern side, surrounded by 8 or 9 fainter stars.

NGC 6819, open cluster, Cygnus

171x. Revisiting this cluster from an earlier session. Not substantially different at this magnification, but retains its richness. Looks a bit like a globular cluster that’s slowly being peeled in half.