Return to the Coma Galaxy Cluster

​14 April 2021, 21:45 – 23:30 (BST)

Seeing: Average / Good

Transparency: Average

Chilly and windy (again). A few scattered clouds blowing south. The previous night’s attempt at astrophotography was blighted by polar alignment issues and a loose power cable. I did however manage to get a 120-second test shot of the Coma Galaxy Cluster, which showed a surprising amount of galaxies for a single unstacked image (see edited crop below). Bodes well for future imaging runs (if the wind ever drops again).

The galaxies near the centre of this image are over 300 million light years away.

Before diving into the galaxies I warmed up with a look at some double stars and a carbon star:

Izar (Epsilon Bootis)

Tight split at 171x. Pale yellow primary; blue-ish secondary NW. I say “blue-ish” because at times it looked vaguely purple (an impossible colour for a star).

Cor Caroli, Canes Venatici

171x. Brilliant bright double; wide separation. Icy white primary; pale yellow secondary.

Y Canum Venaticorum (La Superba), Canes Venatici

171x: Rusty red-hued star, though the colour is due to carbon, not iron.

NGC 3640, galaxy, Leo

171x. Follow up from previous session. As suspected, higher magnification made the difference. I could see a faint field star north of the galaxy, and a very faint, small fuzzy patch (NGC 3641) a similar distance to the south, only just visible with averted vision.

NGC 3705, galaxy, Leo

171x. Large oval haze. Star-like nucleus with averted vision, which also suggested mottling in the surrounding haze (possible s-spiral?). I missed this galaxy on Monday night and I’m not sure why, because it’s quite impressive – certainly not faint or inconspicuous.

 

NGC 4449 (Caldwell 21), galaxy, Canes Venatici

171x. Revisiting a favourite from the Caldwell list. Fascinating irregular galaxy, showing a lot of detail for a non-Messier object. Oblong haze with a bright bar running through it on a diagonal north-south axis. Averted vision showed a bright central spot on this bar flanked by two fainter ones. Averted vision also showed another spot or clump on the eastern corner (as noted in previous observations).

NGC 4889 (Caldwell 35), galaxy, Coma Berenices

171x. The powerhouse at the centre of the Coma Galaxy Cluster (see above). Faint but obvious, as was its slightly dimmer neighbour NGC 4874. Both galaxies appeared to swell in size with averted vision. As both the seeing and the transparency were relatively good I wanted to see if I could pick out any of NGC 4889’s companions (which I’m sure I’ve glimpsed on previous occasions). Once I got my eye in I could see a faint fuzzy spot (NGC 4886) just west of 4889, in line with the 7th magnitude “finder” star HD 112887. On the other side of 4889 and slightly south was a faint foreground star (no fuzziness), and then, a little farther east, another even fainter fuzzy spot (NGC 4898), forming a near right-angle triangle with two field stars to the south. All these galaxies were still visible when I dropped down to 133x, although it was a little more challenging with the comparatively bright HD 112887 in the field of view.

By now the clouds were getting larger, and reflecting a lot of light from the ground as they drifted southwest. With most of Coma Berenices obscured, I relocated to the constellation of Boötes.

NGC 5557, galaxy, Boötes

133x. Round blur; swelled with averted vision. Averted vision also showed a condensed, bright core with a star-like nucleus. Field star west, fainter one east.

SA 2000 plots a handful of other galaxies here, in addition to NGC 5557. I couldn’t see NGC 5529, but I did catch another one before the clouds got in the way.

NGC 5533, galaxy, Boötes

133x. Inconspicuous oval haze, fainter than NGC 5557. Gradually brighter towards the centre; star-like nucleus with averted vision.

The red light on my torch had been getting steadily dimmer throughout the session and now it was so dim I couldn’t see the star-charts or my notes, so it seemed like an appropriate point to call it a night. Though on the plus side, that dimness may well have helped me to see those faint galaxies in the Coma Cluster.

Galaxies in Leo and Coma Berenices

​12 April 2021, 22:30 – 23:30 (BST)

Seeing: Average 

Transparency: Average

Conditions: A clear sky – albeit a little hazy – and still very chilly. For the first time in ages there was no wind, so it was a long-overdue opportunity to set up the astrophotography rig. Problems focusing the ZWO camera meant I was unable to use autoguiding so I was limited to exposure times of one minute. However, despite this and and other technical issues, I was able to salvage something from the session with an hour’s worth of data on NGC 4565 (below).

While that was in progress I sat down with the XT10 to track down some galaxies in Leo and Coma Berenices. After warming up with a quick look at the Leo Triplet, I moved the telescope south.

NGC 3640, galaxy, Leo

133x. Small oval haze, nearly round, aligned east-west. Bright core. Seemed mottled with averted vision. Possible one or two field stars south of the core (reading up on it later, I might have been glimpsing the core of companion galaxy NGC 3641). Might be worth revisiting at higher magnification on a more transparent night.

NGC 3521, galaxy, Leo

133x. Revisiting this gem tucked away in southern Leo. A large galaxy, relatively bright compared to 3640. Elliptical haze with a bright core and a star-like nucleus, aligned roughly north-south. I know the dark lane is on the western side, but to my eye at least it seemed the cut-off was on the eastern side (repeating the observation I made when I looked at it last year).

M99, galaxy, Coma Berenices

133x. Large round haze, brighter towards the centre with averted vision. I feel like I should be getting more out of this galaxy, but there was only the barest hint of spiral structure tonight.

NGC 4298, galaxy, Coma Berenices

133x. Very faint extended haze, aligned NW-SE. Very faint field star on NE side. Averted vision gave the suggestion of an even fainter galaxy to the east (NGC 4302).

M100, galaxy, Coma Berenices

133x. Similar to M99 on first impression, but larger and slightly fainter. Bright core surrounded by a mottled haze. With time and averted vision a vague spiral impression started to form, though – as with M51 – it’s easier to see the dark crescents either side of the core than the spiral arms themselves.

NGC 4340 and NGC 4350, galaxies, Coma Berenices

133x. Revisiting another pair from last year. Two small galaxies in same field, both showing star-like cores. Western one (4340) rounder; eastern one (4350) edge-on with a rough north-south alignment, perpendicular to 4340. 4350 has a brighter, more concentrated core. 

NGC 4450, galaxy, Coma Berenices

133x. Ghostly round glow, aligned north-south. Gradually brighter towards the centre. Increases size with averted vision. Field star to SW.

I rounded off the hour with a look at the same galaxy I was imaging, NGC 4565. Not much I can add to previous notes, although I did look for companion galaxy NGC 4562 which lies at one end of a distinctive arc of stars leading from 4565. Despite my memorising its location, as expected it was a little too faint for me to detect. I think on a really good night it might just be visible in my scope, but tonight was not that night.

Nature note:

Distant noises of foxes barking and revellers revelling (the pubs reopened today after a v-e-r-y long time). Also, while struggling to get PHD2 to work I heard a slurping noise from the pond and looked round to see that a fox had sneaked into the garden for a cheeky drink. Apparently the two telescopes, the laptop and the cursing astronomer were not enough to put it off.

More Spring Galaxies (Leo Minor to Boötes)

​6 April 2021, 21:30 – 00:30 (BST)

Seeing: Good 

Transparency: Average / good

Another very cold, gusty night, with another brief snow flurry during the day. Patchy clouds blowing south again (more so than the previous night). No condensation.

I started the session by revisiting Ursa Major’s two “Alula” doubles, but at a higher magnification.

Nu Ursae Majoris (Alula Borealis)

171x. As per last night: Pale yellow-orange primary and a faint secondary south. Oddly, despite there being a more comfortable gap between the two stars at this magnification, the secondary seemed fainter tonight.

Xi Ursae Majoris (Alula Australis)

171x. A paper-thin but clear split at this magnification. Two almost identical yellow-white stars; primary north, secondary south.

NGC 3430, galaxy, Leo Minor

133x. Very faint, amorphous patch of light; gradually brighter towards the centre with averted vision. This is the most prominent of a group of galaxies in the same small patch of sky, but only this one and NGC 3395 are plotted in the PSA.

NGC 3395 and 3396, interacting galaxies, Leo Minor

133x. Faint pair of galaxies angled towards each other, like a smaller, fainter version of NGC 4567/4568 in Virgo. The western one (NGC 3395) seemed slightly bigger and brighter. Averted vision suggested star-like cores in both galaxies.

NGC 3413, galaxy, Leo Minor

133x. (Plotted in SA 2000). Super faint smear of light, aligned north-south. Only visible with averted vision.

At this point the clouds were becoming larger and more frequent (blowing to the southeast), so I had to keep hopping from one clear patch of the sky to the next to stay ahead of them.

NGC 3242 “Ghost of Jupiter” (Caldwell 59), planetary nebula, Hydra

133x. Bright blue-green oval of light (seemed especially vivid after those faint galaxies). Appeared brighter on the northwest side. Similar impression at 171x, but less intense and softer-edged. Suggestion of darker core with averted vision.

65 Ursae Majoris

171x. Lovely triple star system; good split at this magnification. Two close stars with a more distant one trailing to the east.

NGC 4111, galaxy, Canes Venatici

171x. Bright streak of light with a bright core (as per last night).

NGC 4138, galaxy, Canes Venatici

171x. Faint round haze south of a field star. Brighter towards centre with averted vision.

I couldn’t locate the other galaxy (NGC 4143) plotted near here, so I spent the next few minutes revisiting some old favourites: M3 (showing a lot more stars at 171x), NGC 4565 (171x and 133x) and M51 at 133x. M51’s structure was visible with a little effort, but it looked more like a ring than a spiral tonight.

NGC 2300, galaxy, Cepheus

133x. One of the most northerly DSOs visible in my scope. Appeared as a small, condensed galaxy; bright core with averted vision. While using averted vision I had the impression of a larger, fainter galaxy above it (confirmed as NGC 2276), near a bright field star. 

NGC 2268, galaxy, Camelopardalis

133x. Very faint oval haze. Increased in size with averted vision, which also revealed a small bright core.

NGC 5448, galaxy, Ursa Major

133x. Very faint streak of light, a little brighter towards the centre with averted vision. Almost disappeared in direct vision. Located in the southeastern corner of Ursa Major, east of Alkaid.

NGC 5676, galaxy, Boötes

133x. Large faint oval galaxy, gradually brighter towards the centre with averted vision. The most prominent member of a small gathering of galaxies in northern Boötes.

NGC 5689, galaxy, Boötes

133x. Faint streak of light – lens-shaped or edge-on; smaller than NGC 5676. Stellar core with averted vision.

IC 1029, galaxy, Boötes

133x. Very faint streak of light west of a field star. Like a ghost of NGC 5689, but rotated 90 degrees. Brighter star-like core with averted vision. Located about half a degree from NGC 5676. 

NGC 5631, galaxy, Ursa Major

133x. Conspicuous round oval haze in a sparse star-field. Condensed stellar core with averted vision.

I couldn’t find nearby NGC 5585 (I think galaxy fatigue was setting in), but I did see a dramatic multiple star system west of its location (Struve 1831). I didn’t want to finish the night on a blank, so I tracked down one last galaxy just over the border in Draco:

NGC 5678, galaxy, Draco

133x. Slim oval smudge of light flanked by two field stars. Only very slightly brighter towards the centre with averted vision. Nice pale orange and blue double star due east (Struve 1872?).

Nature note: 

Aside from a fox barking in the distance and two cats fighting out the front, it was very quiet again.

Spring Galaxies (Ursa Major to Corvus)

5 April 2021, 21:30 – 00:30 (BST)

Seeing: Average

Transparency: Average / good

A very cold night for April (there was even a light shower of sleet and snow during the day), with a strong gusty wind blowing from the north. No surprise then that I was wearing full winter gear, but at least the grass was dry and relatively mud-free. As I wanted to minimise the time spent taking my gloves on and off, I stuck with just one eyepiece for the entire session: the 13mm Ethos (a proven galaxy catcher) at 92x.

While my eyes were still dark-adapting, I warmed up with a couple of double stars in Ursa Major:

Nu Ursae Majoris (Alula Borealis)

Pale yellow-orange primary with a faint (possibly blue) secondary quite close to the south (10th magnitude at 7 arcseconds). A third (presumably unrelated) star nearby. An attractive sight to begin the session.

Xi Ursae Majoris (Alula Australis)

White “elongated” star, like a filled-in “8”. Not quite resolved at 92x, but enough to tell it’s a double.

At this point, while glancing away from the scope, I spotted two meteors. The first one (at approx. 21:45) passed through Sextans, heading southwest. About five minutes later another one flashed high overhead through Auriga, heading west. The second one was very bright, although not bright enough to leave a trail or be classed as a fireball. 

On a less interesting note, the sky was crawling with satellites tonight, though I suppose we’re entering that time of year when they’re visible for longer.

M81, galaxy, Ursa Major

For once I didn’t allow myself to get distracted by M82 and, after a while, there was a suggestion of a hazy extended halo, doubling the size of the galaxy. The spiral arms themselves remained elusive, but the haze on the eastern side seemed slightly more prominent, separated from the core by a darker area. The effect was so subtle I can’t really count it as a positive identification of spiral structure, but it does illustrate that most of the time when you’re looking at M81 through a small-to-medium scope, you’re really only seeing the galaxy’s innermost regions.

NGC 3079, galaxy, Ursa Major

Rather faint streak of light aligned roughly north-south. Somewhat brighter towards the centre with averted vision. Similar size to M82. Also: colourful orange / yellow-white double star in same field to east.

NGC 3432, galaxy, Leo Minor

Long, very faint streak of light aligned roughly NE-SW between two field stars. At least three faint field stars superposed over the galaxy.

NGC 3294, galaxy, Leo Minor

Large oval blur, roughly aligned east-west. A little brighter towards the centre with averted vision.

NGC 3310, galaxy, Ursa Major

Small, bright round galaxy south of a bright star. Bright core with averted vision.

NGC 3631, galaxy, Ursa Major

Large, round and diffuse; bright core with averted vision. Suggestion of asymmetry in the halo – I’m guessing this is a spiral galaxy. Also: a bright double star to the southwest.

NGC 3938, galaxy, Ursa Major

Another large round blur, gradually brighter towards the centre. Again, like 3631, a very vague suggestion of spiral structure – seemed brighter on the eastern side. This galaxy is a long way from any useful field-stars, making it tough to find via star-hopping.

NGC 4051, galaxy, Ursa Major

Amorphous round fuzz east of a field star. Star-like nucleus with averted vision.

NGC 4013, galaxy, Ursa Major

Small, lens-shaped streak of light aligned NE-SW. At first glance it appears to have an intense star-like nucleus glinting like a diamond, but I strongly suspect this is a foreground star. (Subsequently confirmed when I looked up the spectacular Hubble image of this galaxy.)

NGC 4111, galaxy, Canes Venatici

An oval smudge of light just over the border from Ursa Major. Bright core with averted vision; another double star to the north.

Next, a detour to Coma Berenices for one new galaxy and one old favourite:

NGC 4494, galaxy, Coma Berenices

Round fuzz ball near the Coma Star Cluster (Melotte 111). Bright core, stellar nucleus; looks a lot like a stray elliptical from the Virgo Cluster. Surprised I haven’t seen this one before, but there is a very distracting galaxy nearby…

NGC 4565, Needle Galaxy, Coma Berenices

Beautiful edge-on galaxy, a spring favourite. Dark dust lane visible with averted vision, becoming harder to see the farther it extends either side of the core. Field star NE of the core.

This was followed with a few more favourites in the shape of M101 and M51 and a quick trek along Markarian’s Chain in Virgo. I’ve had better views of these galaxies before so didn’t take any notes on this occasion. At this point the constellation of Corvus was emerging from behind the neighbour’s tree, so I made my annual attempt to track down the Antennae galaxies…

NGC 4038 and 4039 (Caldwell 60 & 61), interacting galaxies, Corvus

With the exception of M83, spotting galaxies south of about -15 degrees declination is a real challenge from my location. But after carefully sweeping north-northeast of 5th magnitude 31 Corvi I spotted an extremely faint glow within an upside-down y-shaped asterism of stars. With time and averted vision the glow took on a vague shrimp-like appearance, with the northern component looking slightly brighter. I made a rough sketch of the field just to make sure I wasn’t imagining it. Of course, the famous tidal tails would be beyond the reach of my telescope even if the galaxies were overhead, but I was pleased to confirm that the view tallied pretty well with Phil Harrington’s sketch on his challenge page , albeit much, much fainter.

I rounded off the session with quick looks at the globular clusters M5, M3 and M13. Compared to the other two with their tightly condensed cores, M13 looked like a bonbon coated with sugar crystals. (It was late; I was ready for chocolate.)

A Lunar Interlude

22 March, 18:30 – 20:00 

Technically not a deep-sky post, but with the Moon just past first quarter and about as high in the sky as it can get, there's no better time to observe our nearest neighbour. Highlights included the familiar Straight Wall plus the nearby Rima Birt. Another rille was visible inside the rim of the crater Pitatus, as well as a section of the Hesiodus rille (showing a distinctly flat floor). The full extent of the Hadley rille was visible (always an indicator of good seeing) – enabling me to pinpoint the Apollo 15 landing site. Lots of fine detail in and around the Fra Mauro region. Copernicus looming on the terminator (rim illuminated, interior shadowed) with super-fine detail in the surrounding ejecta pattern. This was one of those rare occasions where I used all five Tele Vue eyepieces, although the seeing wasn’t quite good enough to warrant going above 240x with the Powermate.

I also tried Sirius again (this time in deepening twilight, after seeing a tip on Cloudy Nights), but there was still no sign of the Pup. I think the main problem I have is that when Sirius is at its highest altitude from my location, the diffraction spikes from the secondary mirror are always going to obstruct the view of Sirius B.

Nature note:

The dunnock was singing sporadically again, but the most notable observation of the evening was the sheer number of birds seen silhouetted against the moon: waves and waves of them, mostly flying east – and at a very high altitude. The sky was still somewhat blue when I first noticed them through the eyepiece, but they were invisible to the naked eye. It was very difficult to tell exactly what they were, but I would guess they were winter thrushes (fieldfares, redwings) returning to their breeding grounds.

23 March, 19:00 – 20:00

The seeing was even better tonight (although it tailed off steadily once the Moon crossed the meridian). Observations carried out at 171x (DeLite 7mm), 333x (Nagler 9mm + 2.5x Powermate) and 428x (DeLite 7mm + 2.5x Powermate).

Highlights: The three largest Plato craterlets were resolved as actual craters, as opposed to white spots. I couldn’t see the rille in Vallis Alpes, though after reading up on it later I realised I’d underestimated just how narrow it is relative to the valley. Wealth of detail in and around Copernicus – easily the best view I’ve ever had of it. Wrinkle ridges in Mare Imbrium. Cape Laplace (on the edge of Sinus Iridum) casting a very long shadow.

Moving south to Mare Nubium: The rest of the Hesiodus rille was now visible. The concentric crater structure of Hesiodus A was showing very well. Dome visible in Capuanus crater. Ramsden rilles showing really well (reminiscent of the Triesnecker complex). Hippalus rilles (from Mare Humorum) near the terminator.

Also worthy of mention: A very bright ISS pass at 19:30, moving high over the Moon and almost touching Pollux in Gemini. While this was going on I also noticed an extremely bright flare in the east from another object which looked to be travelling on a similar orbit to the ISS, roughly 90 degrees ahead of it. I haven’t yet been able to determine what it was. Stellarium plots several satellites passing through that area around that time (including a few of the ubiquitous Starlinks), but none of them appear to be related to the ISS.

Nature note: 

Still a few birds flying across the face of the Moon, but not nearly as many as the previous evening.