A Visual Extravaganza Under Dark Scottish Skies.

Looking east: sunrise over Wigtownshire.

 

The heavens proclaim the glory of God.
The skies display his craftsmanship.

                                                                              Psalm 19:1

 

Contrary to what you may have heard in the past, the British Isles offer many outstanding places to observe the heavens. Sure, we don’t have vast deserts or majestic mountain ranges that ascend for miles into the sky, but we are truly blessed with many sparsely populated regions, where the activities of human civilisation are minimal. Having lived in Scotland for more than half of my life, I have been fortunate enough to discover many fine locations that offer both very dark skies and good seeing conditions. One such region lies in Wigtownshire, in the extreme southwest of Scotland, in the district known as Dumfries & Galloway.

Not far as the crow flies from the Scottish Dark Sky Observatory, situated to the north of the Galloway Forest Park, the site offers nearly unobstructed views of the heavens from zenith to horizon in all cardinal directions. The gardens are decorated with beautiful beech and cherry trees, the leaves of which vibrantly radiate the rich colours of autumn during sunny spells. By day, there are many places to visit nearby, including the little town itself, famous for having more bookshops than any other in Scotland, as well as rugged country walkways and picturesque seaside villages that adorn the coastline all around the peninsula.

The nearby fishing village of Portpatrick on the west coast of the Rhins of Galloway.

 

During the four nights we spent there in mid-October 2018, we were fortunate enough to encounter long clear spells every night, and with a low-lying harvest Moon setting early, the skies became wonderfully dark, allowing the full glory of the northern heavens to manifest itself. Owing to its location near the sea, the skies here are regularly swept clear of particulates, which makes for exceptionally transparent conditions, ideal for astronomy.

The shores of Loch Ken, near Castle Douglas.

I took along my best travel ‘scope; a modified 130mm f/5 Newtonian, which has proven superior to a string of other, more traditional, travel ‘scopes I have enjoyed in the past, including a TeleVue 76 & 102, a classic TeleVue Genesis Fluorite F/5,  a PrimaLuceLab ED 90 and a variety of smaller Maksutovs in the 90 to 102mm aperture class. With very generous light grasp and resolution, the 5.1” Newtonian has proven to be an enormously versatile instrument for exploring the landscape by day and by night. I also brought along my recently acquired Barr & Stroud 8 x 42 roof prism binocular to soak up ultra-wide field vistas of the northern heavens that perfectly complement the more restricted field offered up by the telescope.

Plotina: the 130mm f/5 Newtonian travel ‘scope used to explore the northern heavens.

 

To get an idea of how good the skies are here, 8 members of the Pleaides are clearly visible to my average eyes once it rises to a decent altitude, as is the North American Nebula in Cygnus. In addition, a string of Messier objects in Auriga, Perseus, Cassiopeia and Pegasus are much more easily discerned visually than at home. The glory of the Milky Way, snaking its way roughly from east to west, is intensely bright here, so much so that at times I considered it a form of light pollution lol.

The patch of land where most of the observations were conducted, looking northeastward.

 

Clear skies come and go here all the time. For a few hours, they remain resolutely clear, then the clouds roll in off the Irish Sea, occluding the celestial realm for a spell before being swept away to the east. Although many calm spells occur at this site, watching the direction of smoke billowing upwards from the chimney of the cottage’s wood-burning stove, indicates that the prevailing winds are gentle and southwesterly in direction. In addition, the site is very quiet and peaceful, naturally arousing deep spritual feelings from within. In the wee small hours, only the sound of gentle breezes whistling through the trees breaks the silence.

The first night proved profitable for outreach. Although this was our third trip to the cottage, a change of ownership occurred earlier in the Summer, when a married couple with a young family underwent a home-coming of sorts, returning to the land of their youth. Their two boys instantly struck up a friendship with our two lads, and so the evening started by showing them the rugged beauty of the Moon, now at first quarter phase, through the little telescope. Nearby Mars proved a little underwhelming though, as by this time it had receded greatly from the Earth in comparison to how it looked in August last, but they were still thrilled to see its little pink disk broiling in the low altitude air close to the southern horizon.

After enjoying some supper, I ventured out later in the evening when the Moon had set to show our guests, which now included the boys’ father, some of the showpieces of the deep sky with the 8 x 42 binocular and the telescope. They were all impressed by the Andromeda Galaxy  and its spooky satellite systems, M32 and M110, using the 25mm Celestron X-Cel LX eyepiece delivering a clean 2.3 degree true field at 26x. The dad was deeply impressed with the Perseus Double Cluster as were his sons, but I also gave them an opportunity to see M57 in Lyra and the beautiful colour-contrast double star, Albireo, well positioned high in the northwest sky in Cygnus. The father was very surprised to learn that the telescope I had brought was quite inexpensive and seemed genuinely interested in acquiring one for himself.

The telescopic views were complemented by carefree scanning of the heavens with the 8 x 42 binocular. Showing them where to point the instrument, they gasped with sheer delight as they beheld the riot of stars centred on Alpha Persei, now high in the southeast, as well the way the binocular broke up the frothy Milky Way into myriad pinpoint stars against a coal-black sky. I don’t think the father had realised just how good the skies over his farmstead could be. I made it clear to him that he was very fortunate indeed to have such outstanding natural beauty on his doorstep!

The second day of our trip (October 16) started cloudy with some light drizzle, but as the day progressed the rain ceased and the clouds began to break up to leave a fine evening. I waited until the Moon was out of the sky before setting up the 130mm f/5 to observe M 15 in Pegasus. Having the 8 x 42 binocular hanging around my neck at all times, I was able to quickly zoom in on this fairly bright Messier object, first with the binocular, which presented the structure as a reasonably bright fuzzy star. By using averted vision, the size of M15 nearly doubled in size to more than half the size of the full Moon. Using averted vision with binoculars is a new activity for me but it certainly pays dividends! The great darkness and transparency of the air at our observing site enabled the decent light grasp of the telescope to be used productively and I was able to resolve a few dozen of its outlying stars using a 4.8mm T1 Nagler yielding 135x, a very tiny eyepiece by modern standards but a true marvel of optical engineering. Much more compact than M 13, the core of M 15 remained very bright and highly condensed, but as it floated through the huge field of view of the eyepiece with its fairly tight eye relief, I brought to mind its prodigious distance; 34,000 light years, far out in the halo of our galaxy.

From there I sped eastwards into Perseus to see how an improved sky would present the large open cluster M 34. Again, the binocular was used to locate the cluster first before centring it in the field low power ( 26x) field of view of the telescope. Even at 26x, the view was very impressive, with a sprinkling of 60 or so stars haphazardly strewn across a field of view roughly the same as the full Moon. The view was immeasurably improved using my trusty Parks Gold 7.5mm eyepiece (87x) which framed the entire cluster with just a little room to spare.

At 22:36UT I recorded an extraordinarily bright fireball, which was extremely long-lived, darting across the sky from north to south. At its brightest it was maybe twice the size of the full Moon and took approximately 4 seconds to fizzle out.

The 8 x 42s also made light work of tracking down the rather elusive face-on spiral galaxy, M 33 in Triangulum. At 26x in the 5.1″ the galaxy took on a ghostly form in an interesting field of mostly 8th and 9th magnitude stars. To my eye, it looked for all the world like a planetary nebula more than a galaxy, with a slight greenish hue. Still, the extra darkness and improved transparency of the Wigtwonshire sky certainly added to the enjoyment of the view. I was particularly delighted by how well the little roof prism binocular could pick it up, as this object has a notoriously large size and low surface brightness.

With the time rapidly approaching local midnight, it was time to have a closer look at the magnificent Pleiades asterism in Taurus. For this target, the binocular proved the superior instrument, with its low power and generously wide field of view (7.33 angular degrees). Riding high in the eastern sky, it was quite simply stunning! Much of the cluster appeared to be enveiled in a fog-like nebulosity which gave it a rather life-like translucent appearance to my eye. No words come close to describiing the full glory of this extraordinary natural beauty and I spent several silent minutes just enjoying the spectacle.

I ended the vigil that evening by examining just a few double stars in the telescope. My notes from earlier years showed how good the site is for conducting high-resolution double star observing during the Summer months, but I wasn’t out to break any records. Suffice it to say that systems that have traditionally been described as ‘difficult’ in more conventional grab ‘n’ go telescopes are beautiful and easily rendered in this instrument. For example, I achieved a most excellent split of the triple system, Iota Cassiopeiae, now very high overhead, using my favourite tools in this telescope for carrying out such work; a 7.5mm Parks Gold coupled to a Meade 3x achromatic Barlow yielding 260x. The three stars were pinpoint sharp (a result of precise collimation using my Cheshire) and the subtle colour differences easily discerned to my eye. Almach (Gamma Andromedae) was gorgeous too at the same power, as was Polaris A & B and  Delta Cygni A & B.

Simply superb for tight double stars; the author’s 7.5mm  Parks Gold eyepiece coupled to a 3x Meade achromatic Barlow lens.

 

Newtonian telescopes are excellent diviners of double stars, an attribute that still appears to be lost on many contemporary amateurs. I have cultivated a theory to explain this anomaly. I suspect that many refractor enthusiasts (onlyists?), accustomed to the hassle-free observing with small refractors, never properly learn how to collimate Newtonians(it does take a while to fully learn the skill!) and, as a result, they attribute their mediocre performance in this regard to other factors and not to badly aligned optics. It’s just a hunch, but I have good reasons to believe it!

With the Moon setting later in the evening of October 17, I gave the telescope a rest and just enjoyed the 8 x 42 binocular. Up until fairly recently, I had forgotten just how wonderful it is to use such a small and lightweight instrument on its own terms. My first target was the magnificent Double Cluster (Caldwell 14) now very high in the eastern sky, as well as the less well-known open clusters surrounding it including the fairly large Stock 2(~1 degree), found by following a curvy chain of stars northwards, away from the twin clusters, and the small and compact (~10’) NGC 957. The binocular view provides a unique perspective that just can’t be replicated in even the smallest rich field telescope.

From there I sought out Kemble’s Cascade, tucked away under Perseus in neighbouring Camelopardalis. A steady hand is a great virtue when deriving the most out of this remarkable linear arrangement of mostly 8th and 9th magnitude suns. Though the cluster is well seen from my home further north, the darker and more transparent skies here made it all the more thrilling to study. For me, binoculars are almost always about hand-held instruments, but I found it beneficial to steady the view on the wooden farm gate on the grounds, where I was able to distinctly make out the small foggy patch denoting the open cluster NGC 1502, where the cascade abruptly terminates.

A little achromatic pair.

 

Though not the best season to explore M 81 and M82 in Ursa Major (they are much higher in the sky in the Spring as seen from the UK), they were very easy to locate in the 8 x 42 binocular despite the constellation’s fairly low altitude in the northern sky at this time of year.  Considerably more challenging though was M51, the famous Whirlpool Galaxy, across the border in Canes Venatici, and even lower down in the sky, which presented in the binocular as a slightly elongated fuzzy patch.

Over in the west, about 8 degrees due south of golden Albireo and on the border with Sagitta, the Coathanger (Collinder 399) asterism was also a joy to observe with the 8 x 42, albeit ‘upside down’ in comparison with the low-power view in the 5.1” reflector. The sense of unity among the stars which comprise the asterism is a pleasant illusion however, as they are actually situated at varying distances from our Solar System. Also nearby, the binocular made light work of tracking down the large planetary nebula M27, which looked like a tiny, incandescent cloudlet against a sable background sky.

Later in the evening, the large and prominent constellation Auriga, represented by a great pentagon traced out on the sky, gained altitude in the east. At its heart, the 8 x 42 presented the three open clusters M 36, M 38 and NGC 1893 very well indeed as foggy patches in a beautiful, rich field glistening with myriad, faint Milky Way stars. M 37 was easy too, just east of the pentagon. About one third of the way in a line from M38 to brilliant yellow Capella, the binocular also swept up the small and faint open cluster, NGC 1857.

As local midnight approached, Taurus had risen to a decent height and it was the ideal time to examine it with the binocular. The generous 7.33-degree field of the 8 x 42 presented the Hyades asterism in all its wondrous detail. Brilliant orange Aldebaran(not a true member however) proved to be a mesmerizing sight, as did the many binocular doubles the instrument picked up immediately to its west. Again, telescopes can’t really do justice to this asterism, as its full glory is hopelessly lost in their much smaller field of view.

As a test, I tried my hand at locating the rather elusive M1 (Crab Nebula) centred on a spot roughly 1 degree to the northwest of the bright blue-white star, Zeta Tauri. I was unable to see anything of this Messier object just hand-holding the binocular, but I believe I achieved success by steadying the view a little on the wooden fence post. Considering that M 1 is a rather lacklustre telescopic object in small and medium aperture ‘scopes, just glimpsing the tiny, roughly 6’ x 4’ smudge was considered a notable visual achievement by this author!

I ended the binocular vigil by welcoming Gemini over the eastern horizon. Though not quite visible to the naked eye owing to its very low altitude at the time of observation, my tiny 42mm ‘double achromat’ made light work of picking up the lovely telescopic open cluster, M35, at the northwestern-most foot of the constellation, together with the fainter open cluster NGC 2158 just next door. This ‘double cluster’ of sorts will look far more impressive when the constellation gains altitude in the coming months.

By half past midnight local time, and with more of the lights from the small, sleepy town nearby having been extinguished, the sky became maximally dark. “The constellations look just like they do in my observing guide!“ I wrote in my logbook.  At the zenith stood majestic Cassiopeia, and ahead of it, Cygnus, now sinking low into the west. Behind it, as if in some kind of grand procession, came Perseus, Auriga, Taurus and mighty Orion looming large in the southeast. The view was so awe-inspiring that I set my binocular aside and just sat in silent contemplation of the lightshow presented to my weary eyes. This, I thought to myself, is the view of the heavens that was accessible to the vast majority of people who ever lived. It had a singular beauty all of its own; just the way the Creator intended it!

And that’s where it all ended on the penultimate night of our stay.

After spending our last day out at Portpatrick(October 18) and a nice family dinner at Bladnoch, we returned to the cottage after dark and to rather more overcast skies. I did venture out to have a look at the waxing gibbous Moon which culminated in the south about 20:00UT when the clouds began to break up once again. Though not a dedicated lunar observer by any measure,  the telescope delivered lovely high contrast images at low and medium powers (up to about 135x). The Moon would not be setting until much later this evening however, so I set the telescope up for work that would not in the least be affected by the encroach of lunar light; double stars.

Plotina; ready for a night of casual double star observing.

 

For this work, I charged the instrument with my Parks Gold 7.5mm eyepiece coupled to a good 3x achromatic Barlow lens yielding 260x and off I went to assess how well the telescope would do this evening. After obtaining lovely splits of Delta Cygni, Iota Cassiopeiae and Epsilon 1& 2 Lyrae, I knew conditions were very good indeed; as they are in many other places in the British Isles. The 1.5″ pair, Pi Aquilae, was a little bit more suspect though, owing to its much decreased altitude in the western sky at this time of year.

A little later, I enjoyed text-book perfect images of Gamma Andromedae, its beautiful colour contrast never faiing to bring a smile to my face. The stellar images in this telescope hardly ever fail to impress. It’s a combination of perfect collimation, modest aperture, good thermal management, adequate light baffling and high-quality optics, but it also requires clear and steady skies, which are accessible to far more observers than has been reported in the recent forum literature.

Two systems in Perseus also proved profitable; Epsilon Persei, with its very faint close-in companion which, of itself, acted as an excellent test of telescopic contrast, and Eta Persei, a lovely wide open, colour contrast double, with a magnitide +3.5 orange supergiant primary and turquoise secondary shining much more feebly at magnitude +8.5.

Finally, this was the evening that I also obtained my first clean split of the tricky system, Theta Aurigae, which was perfectly resolved in the 5.1″ reflector at 260x; my first such splitting of the new season! The difficulty with such a system is the great brightness differential between the components (+2.6/ +7.5) and close angular separation, but the 5.1″ f/5 Newtonian managed it perfectly well as it has done in previous seasons.

I made a quick sketch of how it appeared in the telescope at 22:25 UT (shown below).

An old friend: Theta Aurigae.

 

Note added in proof: On the frigid evening of October 29 at 22:15 UT, in an ambient temperature of -2C, this author took advantage of excellent seeing (Ant I) to obtain his second perfect split of Theta Aurigae of the season using the 130mm f/5 reflector at 260x from his home in rural central Scotland. The Airy disks were round as buttons with a single faint Fraunhofer diffraction ring. Almach (Gamma Andromedae) was spell-bindingly beautiful and calm in the same telescope when examined just a few minutes later.

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Concluding Comments:

The intensely curious & friendly little hens on the farmstead that cannot help but entertain the visitors!

 

It was good to get away.

The weather was settled and mild throughout, with only the occasional spot of rain. All four nights proved to be good and clear for long spells and the days were filled with worthwhile family activities out and about. This is a great place to observe the preternatural beauty of the night sky, tucked away as it is far from the cities and their horrendous light pollution.

We will certainly be visiting again!

We packed up the car early next morning with the intention of getting a good head start on the road back north. Inevitably on such trips, we always leave stuff behind. Sure enough, the owner emailed us later the same evening informing us that he had found a ” telescope cover” aka my flexi dew shield, and a set of earrings belonging to my wife. The boys were not immune to absent mindedness either, as a pair of ankle socks were found inside one of their beds. He kindly offered to post the items back in the week ahead. On Wednesday, October 24, a large yellow package arrived at our home with the said items inside. I emailed him back later the same evening, thanking him for his prompt attention to this matter but also with the offer to reimburse him fully for his efforts. He replied that there was no need:

“The astronomy lesson with the boys and myself was payment enough!”

Fair is fair I suppose lol!

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Appendix: Olber’s Paradox Redux: A Brief Mathematical Treatment of the Consequences of a Dark Sky at Night.

 

In 1823, the German physician and astronomer, Heinrich Wilhelm Olbers (1758-1840) considered an interesting question; why is the night sky dark? At the time, many scientists considered the Universe to be either infinitely old or large, or both. But Olbers considered the logical consequences of this pre-supposition. In an infinite Universe, Olbers reasoned, every line of sight should eventually meet up with the surface of a star. So, the night sky should actually look like the surface of a star. Indeed, the whole sky would appear the same; uniformly bright as a consequence of an infinitely large number of stars. This interesting conundrum is known as Olbers’ Paradox.

A system of stars (or galaxies) arranged in concentric shells with the Earth at the centre.

 

Words can only go so far though, so let us consider the problem from a simple, quantitative point of view.

Suppose we start dividing up the Universe into an infinite number of concentric shells, illustrated in the sketch I’ve made above(apologies for the crudeness of the sketch, as I’m no artist lol), centred on the Earth, with each shell having a uniform thickness, dr. Thus, the volume of each shell (dV) would be the surface area of a sphere of any considered radius r multiplied by its thickness(dr);

So dV = 4πr^2dr.

Now, if there are n stars per unit volume (denoted by asterisks in my sketch), then the total number of stars, N, in each shell will be:

N = 4nπr^2dr.

It is easy to see that the number of stars per shell will scale as r^2. However, the irradiance of each star will fall inversely as r^2, which has a cancelling effect on the overall brightness of each shell and so each shell ought to be uniformly bright.

We must slightly amend the above conclusion, as each star actually has a finite size, with the result that the nearer stars will eventually occlude the light from the more distant stellar members. Still, this would not happen until the entire sky looks as though it is covered with stars. And that returns us to the original conclusion.

Nota bene: The reader will note that each star in the diagram could be replaced by a galaxy with precisely the same consequences!

Let’s now look at possible ways to reconcile Olbers’ Paradox with what we actually witness when the Sun falls out of the sky.  For example, we might consider if the absorption of distant starlight by interstellar (or intergalactic) dust might provide a means of escaping the paradox. Unfortunately, if the Universe is infinitely old, or even existing for just a very long time (say for argument several orders of magnitude older than 13.87 Gyr), then we would expect that such dust particles would have absorbed enough radiant energy to raise their temperature to the same temperature as the surface of a star. And even if it became hotter than the surface of a star, it would merely radiate the excess energy, which the stars would absorb. The consequences are the same though; the sky would look uniformly bright in all directions.

Now consider an expanding Universe, where light is redshifted. In such a case, the energy of each photon of light would decrease as a function of radius, r, so this would help attenuate the brightness of each shell considered above. What happens when we add up individual contributions from each shell? At any fixed radius, the brightness would scale as ∫dr/r, which computes as the natural logarithm of r, i.e. ln(r). But one can readily see that if we choose an arbitrarily large radius, even the quantity ln(r) can become very large indeed, so not ultimately helping us to resolve the problem.

One way out is to consider a Universe that is not infinite in extent, so we can cut off our integral at that finite radius. But there is one other way to achieve the same result, by considering a Universe that has a finite age. Let this age be denoted by t. In this scheme of events, we will only observe stars that are close enough for their light to have traversed the Universe at the speed of light, c. Thus, the radius of that Universe is simply ct. In either scheme; a finite age or finite size, there will exist a limit to the number of concentric shells that could contribute to the brightness of the sky and so the paradox can be resolved!

I find it amazing that from the simple observation that the sky is dark at night, we can arrive at a rather profound conclusion. That said, this analysis cannot, by itself, distinguish which of those scenarios, finite size or finite age (or even both), is the ultimate reason for the darkness of the night sky, but its consequences raise other philosophic/theological questions; if the Universe had a beginning, which has long remained the consensus amongst cosmologists, who or what brought it into existence?

You can’t have an uncaused cause!

To my mind, there is little doubt that the God of the Bible provides the best and most complete answer.

 

In the beginning God created the heavens and the earth.

Genesis 1:1

 

Thus says the Lord who stretches out the heavens, lays the foundation of the earth, and forms the spirit of man within him.

Zechariah 12:1

 

Neil English discusses the work of hundreds of astronomers from the annals of history in his new book, Chronicling the Golden Age of Astronomy.

 

De Fideli.

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