Andrew spots a massive eruptive prominence

At the February 2010 meeting of Sydney City Skywatchers the guest speaker was Associate Professor Mike Wheatland from Sydney University. Mike presented “A Sunspot’s Tale”. Sunpots are regions on the Sun’s surface with strong magnetic fields, a magnetic “storm” if you like. Around sunspots intense magnetic explosions or flares can occur. How flares are actually produced is poorly understood, but they give out intense storms of X-rays.

Typically, from each active region we expect to receive many bursts of weak X-rays and fewer and fewer bursts of more and more powerful X-rays. This sort of pattern, called a power-law distribution, is very common in nature. For example, there are many cities with a relatively small population but only one or two with truly enormous populations. But at some point we would expect the power-law to come to an end because there has to be a limit somewhere to the energy involved in a flare. Unfortunately, this limit has never been seen in the data.

After being very quiet for the last two years, with few or no sunspots for months on end, at the end of October 2009 the Sun produced ‘active region 11029′. Appearing alone it gave Mike an excellent opportunity to study it in isolation. He discovered that it produced many weak flares, as expected, but no powerful flares. Careful analysis showed that it did indeed have the expected limit – something never before observed for an active region. The combination of an isolated active region and one that was small, and therefore incapable of producing very strong flares, had allowed Mike to make his fantastic discovery.

Given that several solar experts were present in the room I took the opportunity to ask for a consensus opinion – has the Sun woken up? Has the next cycle of activity begun? Yes! was the emphatic reply. This is good news for now we can expect to see plenty of large and active prominences, flares and sunspots during the Observatory’s regular solar-telescope viewing sessions.

As if to prove the point today (3 February 2010) the Sun produced a magnificent eruptive prominence. It stretched tens of thousands of kilometres above the Sun’s surface and several hundred thousand kilometres around the limb. Incredibly, we could see it change shape as we watched, something not usually visible. The image below shows the changes over approximately ten minutes! Yes, I think the Sun has finally woken up for solar cycle number 24.

Image by Geoff Wyatt and Andrew Jacob

Harry sees the Sun wake up – a report on the mid January 2010 sunspot AR11040

Sunspot AR11040, drawn by Harry Roberts

2009 December saw the sun unleash a salvo of sunspot groups – with six in the month! As if pausing for breath, the sun has (so far) produced only one group in 2010 January: AR11040. Some observers saw a small group near 11040 mid-month but it survived less than 24 hours and did not get a region number.

AR11040 grew big quickly – and many hoped for a major activity burst – but it was not to be. When first emerging it was said to be the return of November’s earlier group AR11035 that hosted flares up to GOES class C5. This previous group had covered 10º of longitude with penumbral fields of 2500 gauss (the strongest to date), and its preceding (p) spot was sited at 27/253 with the following (f) spot at 29/243.

When AR11040 appeared its (p) spot was at 30/244, the same [coordinates for all practical purposes - Nick] as the earlier group’s following spots! AR11040’s (f) spot was further east at 32/238; the two groups were linked together like railway carriages – but separated in time. Yet the centres of the two groups were 7 to 8 degrees apart – and presumably are separate groups.

My first record of AR11040 was on Jan 8 (Fig1) when it had four elongated (p) spots followed by seven or so (f) spots 6º to the east. Large filaments attended the group and spread over much of the sun’s NE quadrant –an impressive sight – accompanied by bright faculae over a wide area. In H-alpha bright plage threaded through the (f) spot, with a surge at 23:57UT.

Long-lived filaments and faculae are a feature of many C24 spots on returning, and this suggests the new group was indeed embedded within remnants of AR11035 activity. However AR11040’s spots behaved like a new group. Clouds intervened, and when next seen on Jan 12 the group stretched across >ten degrees of longitude – an impressive sight (Fig2) with 16 or more spots in two large penumbral patches. It looked set for ”fireworks” but umbral fields were <2300G and only GOES B class flares.

Changes in sunspot AR11040, drawn by Harry Roberts

Figs 2, 3 and 4 are centrally aligned, allowing us to follow changes between the 12th to the 15th – dotted lines suggest developments “Helio” © freeware had the group’s area peaking on the 12th 22:30 at 400 units over a longitude of 11 degrees. Both (p) and (f) spots had umbral fields of 2300G (Mt Wilson data). On the 15th(Fig4) the group had shrunk a bit and grown less complex, with a large faculae patch preceding – though most of this is due to perspective with the group now 45º west of the central meridian (CM).

Sunspot AR11040 near the Sun’s limb, drawn by Harry Roberts

It seemed AR11040 was waning, but as it neared the limb (16th Fig5) new field with (f) polarity (R18) emerged near the preceding spots (arrow) – an increase in complexity – and some (p) spots aligned to the interloper – a filament, surge and bright plage developed there, but the group’s following (f) component was reduced to a chain of umbral spots (Fig5). Huge areas of faculae and long filaments could be seen, showing that the group was influencing a wide area of the sun. Whatever is needed for big flares was missing in AR11040 – it had many GOES B-class flares and a few C1 and C2 flares – but these are minor events given the its complexity and size.

Yet it was a great subject to study. Will it survive to return on Feb 2nd, crackling with flares? (And what about group AR11041, approaching fast, just behind the east limb- awaiting its turn on the stage!).

[Since Harry wrote the above AR1041 has emerged displaying considerable activity. For updates on what is happening on the Sun see the Spaceweather website - Nick.]

Harry Roberts, Sun and Moon observer and member of the Sydney City Skywatchers

Harry sketches one of the favourite objects in the Australian summer sky – the Great Nebula in Orion

The Great Nebula in Orion, sketch by Harry Roberts

Like most amateurs perhaps, my first view of a nebula was M42 in Orion. In our summer skies the hero’s sword hangs upwards from his belt, and in 1962 a school friend showed me the “sword’s” central star with his 4” reflector. Back then Adelaide streetlights went off at midnight (truly) – and the sky was dark. The impact of seeing the “Great Nebula” for the first time is with me still, and recalls summer holidays of years ago.

For “sky sketchers” M42 is a big task – it‘s very large, with much complex detail, and has a huge brightness range. A while back a friend suggested an attempt on the nebula in pencil, with a series of images recording it in parts. Recently I made a start on the “Orion Project” from my backyard, to be augmented later from darker sites. Before starting I compiled a chart of the main background stars from astro-maps to save observing time The ten inch “dob” and the C8 were both used with the 14mm Radian eye piece – and surprisingly the static image in the C8 at 140x gave the best view. And what a view it was: the sky was surprisingly good with nearby trees enhancing the darkness.

Theta 1 Orionis, “The Trapezium”, was clearly seen as six stars, each brilliant and steady, with 10.5 mag. components E and F bright specks well clear of the four main stars. They all seemed to sit in a darker patch of the main nebula – perhaps a contrast effect. Theta 2 Orionis just to the SE with its two bright neighbours formed a line pointing almost due east. The background of the Great Nebula was peppered with small stars to <11 mag. I set to with pencil and blender to map as much of the nebula as possible over about 2½ hours, adding notes on brightness, detail sketches etc.

E. E. Barnard saw M42 as “resembling a great ghostly bat” in the Yerkes refractor, and Barnard’s “Bat” loomed over the bright nebula on the north side – being the only truly dark part of the whole field – all the rest was luminous to a greater or lesser extent, and it was soon clear that my chart covered only the brighter half of the nebula! The very nebulous star V372 marks the southern edge of my sketch – but is in fact the centre of the whole vast nebula.

Apart from the “Bat’s” wings and head (also called the “fishes mouth”), there was another smaller feature that looked truly black. This was a dark column that seemed to occult the inner bright region of the nebula about 1.5’ SW of the trapezium, with maybe a faint dust tail blowing away southwards; while I’ve viewed M42 many times I’d never seen the dusty feature! Perhaps this object is one of the cooler “trunk-like structures” sustained over light-years by magnetic fields – as some research suggests. This one in M42 is easier to see than most others in, say, the “Eagle Nebula” M16, or the Eta Carina nebula.

There was too much detail to record, and the outer parts of the nebula are only sketched in brief. Within its brightest parts the nebula contains incredible detail too that I will tackle in future sessions with the 4.8 Nagler (X400), and perhaps OIII and Hα filters as well – none were used for this first sketch.

Enjoy the summer nebula – the brightest in the sky.

Harry Roberts, Sun and Moon observer and member of the Sydney City Skywatchers

Harry reports on sunspot AR11036 – part of the recent upturn in the Sun’s activity

A large filament (a prominence seen edge-on) near sunspot group 11040 on the morning of Sunday 10 January 2010. Image taken in red hydrogen light by Monty Leventhal OAM

In H-alpha the sun can be amazingly active, but during solar minimum such activity has been rare. Material can be ejected from the sun in a variety of ways – and perhaps the strangest is the surge.

Surges occur near sunspots with strong umbral fields. Around such spots the chromospheric granularity is often very disturbed, and looks like long grass blown over by strong winds. Often in such regions dark (i.e. cooler) material can erupt from a point within or near the penumbra of a large stable spot, yet the material remains confined within a field structure. And what we see may at first look like more disturbed granularity – but the ejecta may then travel across a great distance (tens of Mm) often in a graceful curve. Sometimes a salvo of surges will erupt side by side as recently occurred in AR11036. Having reached a maximum distance from the “parent” spot – the surge often pauses for some time, before retracting backwards (backflow) along its original path – to disappear where it first emerged! While this sounds implausible, surges are relatively common around certain spots.

Sunspot AR11036, drawn by Harry Roberts

AR11036 emerged in the sun’s SW quadrant about Dec 20, with a few tiny preceding (p) spots and two or three larger following (f) spots, these in one penumbra (Fig). When I first saw it, alerted by Monty L, it was attended by several surges, including a trio (or salvo) over 40Mm in length. Other lesser surges or patches of disturbed granularity emerged from the group at points on the NE side. Sub flares were seen where the surges emerged – as is often the case. None of these were strong enough to cause a spike in the GOES X-ray background of GOES B1-class. A dark active region filament (arf) connected p and f spots, with bright plage throughout (Fig 1). No retraction phase was seen.

Shortly after (22:53UT) the same group appeared to host a filament ejection (Fig 2). This time very dark material emerged from points both south and north of the f spot group. This followed similar paths to the earlier surges, but was strongly tuneable in H-alpha – suggesting a Doppler shift in approach (i.e.bluewards). This suggests the ejection of one or more active region filaments (arf), as a strong shift is not usual in surges (that mostly stay near the solar surface – near vertical surge is a possibility). While this ejecta was visible on-band (central Hα) it grew very dark off-band while all other Hα detail vanished – a sign of high velocity in approach along line of sight. Strong flares usually follow filament ejections but only a sub flare was logged at 22:53 UT. A B4 at the site 40 minutes later may be associated, and the strongest C24 flare to date a GOES C7 erupted at the site six hours later together with a CME.

Clearly this small group was unusually active – having the strongest flare to date. Yet its white light appearance was that of a very minor group. It faded rapidly, and when near the limb the Mt Wilson Magnetograph recorded no detectable umbral field – Mt Wilson having been closed previously by weather conditions. We must guess at AR11036’s peak umbral fields – they were presumable strong, and recent northern group AR11035 had the strongest field yet for C24 of 2500 gauss. Are we witnessing a strengthening of C24 magnetic fields? Keep sun watching.

Harry Roberts, Sun and Moon observer and member of the Sydney City Skywatchers.

Harry provides an easy guide to the splendours of the winter Milky Way from Australia

Part of the winter southern Milky Way with the constellation Sagittarius outlined and some Messier objects numbered. The cross denotes the centre of the galaxy. North is to the left and south is to the right. Photo copyright Harry Roberts

“Girt by trees” best describes my yard – with clear sky only at the zenith. Still, there are no street lights and I was surprised by what could be seen in 8 X 40 binoculars, particularly when a reclining seat and headrest were used.

Access to the Crux – Centaurus regions is poor, but most of Scorpius and Sagittarius passed overhead in stately procession during winter. In fact, the binoculars showed much galactic structure, and the 10” ‘scope stood ready to reveal the details.

This, then, is a brief outline of the winter Milky Way in binoculars– much more would be visible at a dark site – and refer to the Figure, a film mosaic, in which the Sagittarius “Teapot” is outlined as a guide.

The brightest part of our galaxy visible to the naked eye is the region known as the Great Sagittarius Star Cloud (GC in Fig and likened to “steam” from the “teapot’s spout”) – this is a dense halo of yellow population II stars at the centre of our galaxy dating from its early formation. These stars cluster around the galactic core 30,000 light years away – so we actually see part of the core, but only on its southern side (Fig 1 middle right).

Another bright star cloud is the Small Sagittarius Cloud (SC in Fig., Messier 24) but unlike the GC the SC is only 16,000ly away, and its young blue stars show it to be a star forming region – a beautiful area in binoculars and easily seen with the naked eye. The population I stars in this cloud are only a few million years old, compared to billions of years for those in the Great cloud!

Along the galactic equator chains of dust clouds, often called the Great Rift (see Fig, from top left to bottom right.), hide most of the galaxy’s central regions. The galaxy centre, at galactic longitude 0º (or 360º) and latitude 0º, is located with a cross in the image. The top left of the image is galactic longitude ~340º, and bottom right is longitude ~20º; the Fig showing about 40º of longitude.

Much of the equatorial Rift is visible to the naked eye, and its darkest part is the “Pipe Nebula” just left of the galactic centre (Barnard B56 and B78). Many stars lie along this thin dark cloud and presumably formed from it – it’s the largest dark “trunk” structure I know of, and “easy” in binoculars. These “trunks” of cosmic dust may be held together over hundreds of light years by interstellar magnetic fields, and a more well known example is NASA’s “pillars of creation” in Messier 18 imaged by the Hubble ‘scope.

Scattered along the galactic equator are several compact H-alpha emission nebulae. When hot young stars begin to emit lots of UV light they cause their surroundings to fluoresce in both H-alpha and other wave bands. Several are easily seen in binoculars, the brightest being the Lagoon Nebula M8. Close to the Lagoon but very faint in binoculars is the Trifid Nebula M20. Near the bottom in the Fig is the Omega Nebula M17, also easy in binoculars although its famous “swan” shape needs a ‘scope to be seen. These glowing clouds are about 5 – 6,000l.y.away – fairly close in galactic terms (although summer’s Orion Nebula is only 1200l.y away). And presumably the dark clouds that obscure so much of the galactic equator lie at the same distances, and a puffy cumulous texture is seen in them at several places in binoculars.

Finally, I suggest a look at rich galactic clusters M6 and M7, both about 1000l.y away. Globular clusters abound in this region too – try M22, third or fourth brightest in the whole sky, a superb object in binoculars. The globulars form a halo around the Milky Way and so M22 is more distant than our other objects, about 20,000l.y away.

Winter in the southern hemisphere – the best time for “gazing” at the large galaxy in which we live, with both unaided eyes and a pair of binoculars.

Harry Roberts, amateur astronomer, Sun and Moon observer and member of the Sydney City Skywatchers.

Harry watches as a sunspot group (almost) returns: AR 11029

Prominences on the Sun on 14 November 2009 (Australian time zones), drawn by Harry Roberts

Much of the fun in Sun watching is to monitor events unfolding at a given site over time. And we need to know where we are on the Sun for this to work. Helio freeware and a cross hair eye-piece is my method – there are others.

Sunspots are attached to the solar core by an umbilical cord of braided magnetic “ropes” that can often be seen (as faculae and plage) even before spots emerge. The strength of the field within these ropes is a good guide to a sunspot’s lifespan and how big it will grow.

Strong magnetic fields are not often found on Earth, outside the CERN device or a specialist lab, but they are common on the Sun. And fields grew quite strong in spot group AR 11029 in late October. From a scattered cluster of small spots it grew into an impressive penumbral group, closing with the Sun’s NW limb on the 30th. Many remarked on its large preceding (p) spot that at the time had striking penumbra and bright faculae. Fields inside this spot reached 2400G as logged by the Mt Wilson 150’ telescope; the strongest for any C24 spot group thus far.

As it passed behind the west limb we speculated whether it would survive to make a second transit of the Sun’s visible disc; well, it almost did! Spaceweather.com kept up a commentary as AR11029 transited the Sun’s far side – imaged by solar “seismology”, and speculated on a “grand reappearance” at the east limb around November 14.

“Helio” software gives solar coordinates for any point on the Sun, and on the 14th the longitude of the east limb was again 220 degrees, the longitude of the p spot of AR11029. On that day I searched the limb with no sign of the big spot from 30 October – no spots were visible at all, but prominences were active at the site suggesting the magnetic “ropes” were still strong there (Fig 1) as active region filaments.

A region of bright faculae on the Sun, drawn by Harry Roberts

The 15th (the next day) showed an amazing sight: a vast region of bright faculae stretched across the site that had been AR11029 14 days earlier (Fig 2). “Helio” put the leading edge of this vast bright area at +16/224 (16ºN, longitude 224) and the trailing end at +22/216. Remembering that AR11029’s p spot was sited at +16/220 and f spots at +16/214, we see that this region of faculae lay right at the spot group’s earlier site.

And interestingly Mt Wilson’s 150’ ‘scope saw a single tiny spot on the 14th at 16:15 UT located at +14/217, centred within the faculae. It was not visible in Sydney only 6 hours later! No “grand return” for the most active spot group of C24 occurred; yet the vast spread of faculae was so impressive in WL that it almost made up for AR11029’s non-appearance.

Harry Roberts, Sun and Moon observer and member of the Sydney City Skywatchers

Harry asks whether sunspot group 11029, seen in October 2009, will come back?

Sunspot group 11029 at the edge of the Sun, drawn by Harry Roberts

A brief view of this active C24 spot group was had as it approached the solar limb. Only a short view through gaps in trees was possible using the portable 4” Maksutov on its wooden tripod.

It was a surprising sight – I can’t recall any group over the last two years with such bright faculae. Faculae are extensive monopolar areas, although they are usually present as a large patch of N polarity and a large patch of S.

Indeed, the whole group was meshed in vivid faculae. I assume equally bright H-alpha plage was present though no observation was made in that band.

The large preceding p spot was a complex entity. It seemed to be a horse-shoe shaped penumbral region with very bright faculae within. Edging the inside of the penumbra numerous small spots were seen on the east side and a single, or maybe double, thin black umbra on the west side.

The following f spots were few; with two or maybe three areas of penumbra 8 or more degrees east of the p spots. There seemed to be 4 or five umbrae within the f spots. Swirls of vivid faculae trailed the group. It was a great sight – and reminded me how much more impressive a big spot group is in white light than in lower contrast H-alpha.

GOES X-ray plots showed high levels of flaring up to C1.7 – though I recorded only a B3 two days earlier. AR 11029 unleashed another C1 when right at the limb on the next day that coincided with a small but impressive CME at 09:00 UT (see spaceweather.com for the 31st Oct).

Cross-hair timings gave the following heliocentric coordinates:
Centre of the “horse-shoe” p spot: +13/217
Centre of the whole group: +14/213
The solar limb adjacent: +10/233
These show the group was sited about 20º from the limb, and stretched across about 8º of solar longitude (i.e. longitude length LL=8º)

AR11029 raises interesting questions: will it return, grown larger? Will a large spotless faculae region (FR) return in its place? Or will there be no trace of it in roughly 14 days from now when this region of the solar surface swings into view once more?

Harry Roberts, expert Sun and Moon observer and member of the Sydney City Skywatchers

Dr. Nick Lomb and Assoc Prof. Wayne Orchiston awarded Life Membership of the Sydney City Skywatchers.

Dr Wayne Orchiston, Mike Chapman President of the Sydney City Skywatchers, Dr Nick Lomb and Henry Chamberlain Russell on the monitor to the right.

The Sydney City Skywatchers, are the oldest operating astronomical association in Sydney. Formed in December 1895 as the New South Wales Branch of the British Astronomical Association they operated under that name until September 2004 , when the name was changed to Sydney City Skywatchers. The group has been meeting at Sydney Observatory for many decades and Observatory astronomers have traditionally held senior positions on its committee; the curator of astronomy, Dr Nick Lomb, has been a member for at least thirty years. Wayne Orchiston joined when he was only 13 years old in the 1950s and remembers a large number of young budding astronomers doing observations at night and attending lectures.

Sir Patrick Moore, well known British astronomer, is also a lifetime member and in the 1980s presented a talk at one of the meetings in Sydney Observatory to a packed audience. The group is an affiliated society of the Museum.

Stevenson Toner
Manager, Sydney Observatory

Harry sees a rare spot on the Sun and it is a large one – AR 11029

Sunspot AR 11029 on the surface of the Sun on the morning of Thursday 29 October 2009 (AEDT), image courtesy SOHO/MDI

The Astronomical Society of NSW (ASNSW) field day at Epping (Oct 24) was successful partly because there was something to see on the Sun. Members of the public could watch an emerging string of spots (AR11029) and when told they stretched across 50,000 km were suitably impressed. As well the clouds had more gaps as the day wore on. Half a dozen ASNSW members showed the Sun with a variety of methods, from image projection to narrow-band filters.

Sunspot AR 1109 (fig 1), drawing Harry Roberts

AR 11029 showed a tight cluster of small dark spots at the following (f) or east end, with a hint of two isolated spots well to the west (p) of the cluster. Timings showed the group covered about six degrees of longitude (Fig 1). In H-alpha some plage and a dark filament was recorded.

Sunspot AR 1109 (fig 2), drawing Harry Roberts

Clouds and heavy rain prevented further views until Oct 28 – when big changes in the group were obvious (compare Figs 1 and 2). During our cloudy days the professional websites showed rapid development in AR11029 and a big rise in GOES flaring, with several C class flares and dozens of lesser events. Fig 3 shows a B3 flare and associated ejection of dark material with detectable Doppler shift – a presumed filament ejection.

The writer keeps watch on the daily Mt Wilson umbral field magnetographs recording field strengths inside the sunspots themselves (hand-drawn). As you know current research suggests the sunspot fields have fallen to historic lows – and further decline is predicted. Figs 1 and 2 show the group in WL and H-alpha combined with the magnetograph closest in time on the right side of the Fig. (Note these are reversed project images).

AR11029 emerged (23rd Oct) with slightly stronger fields (2100G) in the (f) spot cluster and only 2000G in the isolated (p) spots. But things quickly changed. Even during the field day the isolated (p) spots became more distinct as they grew rapidly, although none seemed to have penumbra at the time. The magnetographs show that over the next few days stronger field emerged in the (p) spots while the (f) spots faded and disappeared – the tendency was for the group to shorten and concentrate magnetic flux at the western (p) end.
Fields there reached the strongest level yet recorded for a C24 spot of 2400G on the 27th. It’s easy to overstate the field strength argument. Several penumbral spot groups belonging to C24 have appeared since the cycle commenced in January 2008. The strongest fields recorded prior to the current group were 2300G in AR11024 (Jul 09) and 2300G in AR11008 (Nov 08). AR11019 had 2200G in May 09. So while 2400G is the strongest C24 field yet seen it represents only a small increase (100G) on the previous records – perhaps close to the equipment’s detection limits. Remember spots disappear around 1800G, and note the many at this level shown in Figs 1 and 2.

Sunspot AR 1109 (fig 3), drawing Harry Roberts

Through much of the 20th century sunspot fields were typically 3000G, yet the McMath-Pierce team find average fields currently at only 2200G. Do the 2400G detections suggest a turn-around in solar core fields? Clearly it’s too early to know. The present shortage of large prominences, disc filaments and penumbral sunspots confirms the weak core fields – and a turn-around may be a long way off. Still it was good to see an almost “normal” looking sunspot (Fig 2 and 3) with penumbra, visible filaments and some modest flaring.

Harry Roberts, Sun and Moon observer and member of the Sydney City Skywatchers

Harry finds a swan-like nebula – M17 the Omega Nebula

Omega Nebula drawn by Harry Roberts

Sketches of deep sky objects won’t win photographic competitions – but it is interesting to learn what that amazing detector, the human eye, can see through a telescope.

Discussing this recently I learnt that extended objects do not grow brighter as you approached them, and remain faint and colourless to human eyes. And the reason that digital sky images show rainbow hues is because cameras accumulate photons over time and so detect the true colour of the emitted light, red H-alpha, blue H-beta and green OIII etc. Having evolved on a planet with both dazzling sunlight and deep darkness our eyes lack the ability to see colour in faint extended sources.

When I came across M17 in the ten inch I realised I had forgotten how bright it was – a stunning swan shaped object that looks pretty much like its digital portraits – but with no sign of colour. Time is needed for a good sketch (as it is for photography) so the C8 (with diagonal and LPR filter) was used for this impression. Though the subject was fainter in the 8” the fixed image allowed more to be recorded (See sketch above).

The “swan’s” bright horizontal bar has much subtle detail with dark bands crossing it, and a milky light with brighter streamers formed the ghostly folded wings above the its “back”. The dark nebula below the swan’s neck stood out strongly as the darkest part of the whole field, with fainter nebula creating the “neck”. The head and bill of the celestial swan could be seen too, but unresolved stars may cause this. The “water” on which the swan floats was not dark either; faint wispy nebulae were visible there with averted vision.

Looking closely several faint stars were seen in the nebula –exaggerated in my sketch – as none of them were brighter than ~9 magnitude.

Messier saw it as “A train of light without stars, 5’ or 6’ in extent, in the shape of a spindle, a little like that in Andromeda’s belt (M31) but the light is very faint”. William Huggins was the first to study the light of M7 in a spectroscope (1866) and announced that the cloud was truly a mass of glowing gas, not a cluster of unresolved stars as Herschel senior thought – and it was the latter who coined the more common name Omega Nebula.

M17 is about 6,000 light years away and 12 light years from end to end. It is a very bright nebula, a good target for small ‘scopes, and visible as a bright patch in 8X40 binoculars; maybe it’s a naked eye object at a really dark site – a truly stunning winter [and spring] object!

Harry Roberts, sky sketcher and member of the Sydney City Skywatchers