A Magical Evening with Plotina.

Plotina; the author’s 130mm f/5 Newtonian still strutting her stuff.

It’s hard to believe that four long years have gone by since I first discovered the considerable virtues of a modest 130mm f/5 flextube Newonian reflector. Like the larger 8-inch f/6 Newtonian I switched to in 2015, this 5.1 inch instrument has proven to be an excellent all-round performer, doubling up as a high performance spotting ‘scope by day and a fantastic grab ‘n’ go telescope at night, where its very decent aperture, fine optics, light-weight portabiity and quick cool down time has yielded excellent views of the Moon, bright planets, deep sky fuzzies and a whole raft of double stars.

Shortly after testing the basic SkyWatcher unit, I invested in some modest-costing upgrades to further enhance the performance of this telescope. The secondary mirror was upgraded to one of higher quality and slightly smaller size (26.9 per cent linear obstruction). In addition, I had both the original SkyWatcher primary and upgraded secondary re-aluminised with Orion Optics UK’s proprietary HiLux coatings with 97 per cent reflectivity, giving an overall transmission of 90 per cent at the eyepiece once the area of the central obstruction is also factored in. The original flextube was replaced by a solid aluminium tube from a SkyWatcher 130P, providing a more stable arrangement for the secondary mirror housing. The tube was lined with cork and overlaid with flocking material to minimise stray light and increase image contrast. Finally, both the primary and secondary mirrors were equipped with Bob’s knobs to facilitate easy and quick collimation of the optical train. The resulting instrument sits pretty on a light weight alt-azimuth mount – a Vixen Porta II – which can be used both terrestrially and for astronomical observations.

The Vixen erector lens system used to obtain correctly oriented views with Newtonian reflectors.

In previous blogs I investigated ways to use this small reflector as a terrestrial spotting ‘scope, discovering methods to enjoy correctly oriented terrestrial views using a Vixen erecting adapter.The device allows the use of any eyepiece, thereby creating a spotting ‘scope with a much larger range of magnifications than those offered by conventional spotting ‘scopes. Its much greater light grasp allows me to enjoy crisp and bright high-power images well into twilight.

The 130mm f/5 Newtonian in terrestrial spotting ‘scope mode using the Vixen erector lens.

My 130mm f/5(aka ‘Plotina’) has travelled all over the British Isles with me, safely packed away in its foam-lined aluminium carry case, where it has sampled great skies in southern Ireland, northern England, Scotland and south Wales. These observations strengthened my conviction that there are many places where conditions are good enough to push the resolving power of this Newtonian telescope. Indeed, I have been able to split sub arc second pairs(0.9″) at ultra-high powers (up to 405x) in many of these locations. During summer heat, cool autumn and spring nights and freezing winter evenings, the telescope has never disappointed. Indeed, it has greatly exceeded all my expectations for it!

Portable powerhouse.

Best of all, it has saved me an absolute fortune, allowing me to completely break free from using small, expensive refractors, which became somewhat of an obsession with me for the best part of a decade. And quite frankly, to go back there again would be bonkers!

February 25 2020 Observations

Time: 21:20 to 23:15

Conditions; Cold (1-2 C), mostly clear and transparent skies with no Moon and with intermittent blustery west or northwesterly gusts. Seeing very good (Ant II).

Although the telescope optics takes a good 30 to 40 minutes to obtain the best high power images when taken from a warm indoor environment, it most certainly can be used with immediate effect if you start with low power wide field targets. I’ve recorded quite a few instances in which antagonists claim that the same telescope takes too long to acclimate to be a real grab ‘n’ go contender, but this is based largely on ignorance, laziness or just plain old lack of resourcefulness. In addition, it’s important to stress that I do not employ cooling fans on this or any of my other telescopes.

Accordingly, I initiated the session with low power (26x), larger deep sky objects, beginning with some showpiece open clusters such as the Double Cluster in Perseus, which was beautifully rendered in the wide, 2.3 degree true field served up by my Celestron X-Cel LX 25mm ocular.  From there, I ventured over to the large and bright open cluster M34 (also Perseus) enjoying several dozen stellar members, many of which are arranged in neat double or triples(mostly telescopic in nature), and then ventured southward into Gemini now sinking into the western sky, where I enjoyed a stunning view of the expansive M35, the excellent light grasp of the reflector showing up many fainter members that are either invisible or very faintly rendered in smaller (4-inch and under) refractors. The 130mm F/5 is a particularly good telescope for observing this sprawling Messier open cluster, combining the near-ideal combination of aperture, magnification and field of view to fully immerse myself in the view.

Camelopardalis was well situated high in the sky and so I sought out an opportunity to track down Kemble’s Cascade, so named after the late Canadian observer, and Franciscan friar, Father Lucian Kemble(1922-1999), who first called the amateur community’s attention to this remarkable, linear array of  15 or so stars tumbling down to the small open cluster NGC 1502 across the border in Cassiopeia. Spanning a full 2.5 angular degrees, Plotina was not quite able to encompass the cascade in its entirety. That said, the telescope served up a wonderful sight of stars ranging in brightness from the fifth to the 9th magnitude of glory. It is all the more remarkable that Kemble actually chanced upon this visually striking asterism using diminutive 7 x 35 wide-angle binoculars!

After spending a few minutes drinking up the view of the mangnificent Beehive Cluster M44 in Cancer, the telescope was now sufficiently well cooled to crank up the power to get some close-up views of the three Messier open clusters in Auriga. For these, I employed a power of 118x(Meade Series 5000  5.5mm UWA) in a generous 0.7 degree true field. All three clusters are visually striking in the 130mm f/5 at this moderate power, but by far the most fetching in my opinion is M36, which transforms from a small foggy patch about one third of the size of the full Moon in 8 x 42 binoculars(also accompanying me at the telescope) into a granular mound of faint stars some 5 dozen strong. Increasing the magnification to 135x using my 4.8mm T1 Nagler improved the view still further by helping to pull the faintest members of this cluster out of the background sky.

I was now ready to visit a suite of my favourite seasonal doubles well placed for observation on late February evenings. I began in Auriga, centring the bright white star Theta Aurigae. Cranking up the power 236x(Meade UWA 5.5mm and 2x Orion Shorty Barlow) and carefully focusing, I was delighted to obtain a near perfect image of the bright primary and the spark of the much fainter secondary tucked up close to it. This is quite a tricky system to image well though, and is thus a good test of seeing conditions at my backyard observing site, but tonight presented good conditions(as they often do here and elsewhere), so I knew that visiting a few other tricky systems would be a worthwhile pursuit on this fine evening.

Off I sped to enjoy an easy system first; Castor A & B, which was beautifully rendered at 236x in the 130mm, the two bright components presenting as pure white Airy disks, with the much fainter C companion easily seen wide away. From there I moved the telescope a little way ‘down’ the western sky until I centred  creamy Wasat (Delta Geminorum). The challenge here is to bag the exceedingly faint and close-in companion shining nearly five stellar mangnitudes fainter. I have found, through experience, that the Meade UWA 5.5mm yielding 118x provides the most compelling view of this optically delicate companion. The older 4.8mm T1 Nagler is not as good as the newer Meade ocular in showing this system at its best. I attribute this to slightly better coatings applied to the newer eyepiece. Attempting to push my luck, I panned the telescope a little to the northwest to the lovely marmalde orange star, Eta Geminorum(Propus) but even after crankning up the power to 270x and 354x, I was unable to resolve its very close-in companion. That said, this system was by now well past meridian passage and sinking lower into more turbulent air in the western sky.

As the evening progressed, Leo was now beginning to assert itself still somewhat east of the meridian. After a few minutes enjoying the rich aureal tints of Algieba(Gamma Leonis) and its companion, I panned the instrument southeastward until I centred Iota Leonis in the 6 x 30 finder accompanying the main telescope. This is quite a challenging system to resolve, consisting as it does of a 4th magnitude yellow-white primary and 7th magnitude secondary in a close-in orbit. Starting with 238x, I was able to discern the secondary as a tiny pimple like projection off the primary, but when I cranked up the power to 354x (3x Meade achromatic Barlow and 5.5mm Meade eyepiece),  and watching the system move rapidly across the field from east to west, I was finally able to see the secondary intermittently detached from the primary.  That said, I could have done with another hour and a half of waiting until it reached its maximum altitude in the south, but I was just happy to be able to resolve the system reasonably well at this earlier time of about 11pm local time.

Re-visiting Cassiopeia, still well placed high in the northern sky, I was able to enjoy a wonderful view of the lovely triple system, Iota Cassiopeia, which was easily resolved into its three components at 236x with the 130mm Newtonian. Nearby Eta Cassiopeia, with its comely red and yellow components widely spaced at 236x was also a worthwhile system to visit on this cold February night. Images remained sharp, crisp and contrasty even at these high telescopic powers.

Taking a quick break with my 8 x 42, I ventured to the front of the house, where I noted a rather lobsided Plough high in the northeast and lower down, the main stars of Bootes had by now cleared the murky air above the Fintry Hills to the east of the house. I then decided to move the telescope on its Vixen Porta II mount(which I can easily manoeuvre with one hand). Aiming my 6 x 30 finder at the two Alulas in Ursa Major, I centred each system in turn in the 130mm reflector. Alula Australis was truly a sight for sore eyes at 236x, the two stars presenting with beautiful, round yellow Airy disks separated by a sizeable sliver of dark sky. This is a fascinating system to watch with a small backyard telescope, where both 4th magnitude components complete one orbit of their barycentre in just 60 years! Ruddy Alula Borealis presented a different kind of challenge though, rather like Delta Geminorum observed earlier in the vigil. Using the very high contrast views of the Meade UWA 5.5mm, I was able to just make out the tiny and very faint spark of light of its close-in secondary at 118x.

I ended this late February observation session by trying my hand at Epsilon Bootis(Izar), a favourite Spring binary system. still quite low in the east at or shortly after 11.15pm local time. Deciding on a moderately high power of 238x, Plotina managed a decent split of this gorgeous colour-contrast pair(yellow and blue), but its low altitude was, of course, attended by increased atmospheric turbulence.

The title of this blog included the word, ‘magical,’ with the implication that there was something out-of-the ordinary about what the 130mm Newtonian can show. The truth is that these targets, especially the high-resolution systems discussed, can be enjoyed fairly routinely with this telescope from many locations(you just have to test them) and it is my fondest hope that others will take up the same challenges with their small Newtonian relectors.


Neil English has created a considerable volume of literature highlighting the many attributes of the 130mm f/5 Newtonian. He is seriously considering writing a full length manuscript of his experiences with this transformative instrument at some time in the future.


De Fideli.



For the Record.

Plotina: raising the bar for grab ‘n’ go astronomy.


2018 was not an unusual year here in Scotland, as astronomical observing and associated note-making are concerned.

Total number of nights where observations were made in 2018: 137

Percentage of nights available for observation in 2018: 37.5 per cent.



2019: I recorded 135 nights of clear or partially clear skies. This represents 36.9 per cent of nights available for observation.

These numbers continue to be in accord with the claims of several British historical observers; T. W. Webb, William F. Denning & Charles Grover.

For more details on this interesting topic, see my 2018 book: Chronicling the Golden Age of Astronomy.


De Fideli

Old vs New.

How does a classic Zeiss binocular square up to a modern roof prism binocular?

Unlike telescopes, which are mainly used by dedicated amateur astronomers, binoculars, for obvious reasons, are owned and used by a much broader cross section of the general population. When my students get to know me, they will inevitably have to endure my unbridled enthusiasm for optical devices of all kinds lol, and that includes binoculars. One of my mathematics students, Sandy, expressed an unusual interest in some of my instruments, and he further informed me that his parents, who run a small ferrying business at Balmaha, on the shores of nearby Loch Lomond, used several binoculars in their everyday work. My interest was further piqued when Sandy told me that his grandfather owned a big Zeiss binocular, which was inherited by his father and would eventually be passed on to him in the goodness of time. I asked Sandy whether he would be willing to bring the Zeiss binocular by so that I could have a look at it. After checking with his parents, Sandy agreed and kindly allowed me to use it for a week in order that I could assess it and give it a good clean. Naturally enough, I jumped at the opportunity!

The instrument, a Carl Zeiss Jenoptem 10 x 50W porro prism binocular, came in a lovely leather case; a far cry form anything made in this era.

The Zeiss Jenoptem 10x 50W complete with original leather carry case.

The instrument had no lens caps and so had accumulated quite a bit of grime on both the ocular and objective lenses over the years. The Jenoptem, which was manufactured in East Germany(DDR), featured a Zeiss multi-coating, which helped me to date it to after 1978, when the company apparently began to apply their anti-reflection coatings to all the lenses and prisms in the optical train. So my guess is that it was probably acquired in the early 1980s. I believe Zeiss Jena offered a higher quality porro 10 x 50 in the Decarem line around the same period, but I have not had the pleasure of testing one of these units out.

The Zeiss Jenoptem is multi-coated.

The instrument has a very Spartan look and feel about it. Weighing in at about 1 kilogram, the Jenoptem is built like a proverbial tank, with a central focusing wheel and right eye dioptre.Turning the nicely machined metal focusing wheel first clockwise, and then anti-clockwise, all the way through its trave,l showed that it was still in excellent working condition, with zero backlash and bumping that one usually encounters with cheaper porro prism binoculars.

As expected from Zeiss, the Jenoptem has a very well made focuser that moves with silky smoothness and with zero backlash.

To begin the cleaning process, I unscrewed the objective housings from the front of the binocular in order to get at the inside surface of the objective lenses, which had a significant amount of grime as well as a small amount of fungal growth. Using a good quality lens brush, I carefully removed much of the dust before using a microfibre lens cleaning cloth soaked in a little Baader Optical Wonder fluid. In just a few minutes I was able to remove the remaining grime on both the outer and inner surfaces of the binocular objectives, as well as the surfaces of the prisms in the rear module of the instrument. The ocular lenses were also given a good cleaning.

The objectives of the Zeiss Jenoptem can be accessed by uncrewing the front of the binocular from the prism and ocular housing.

I was able to verify that the prisms were indeed coated in the same way as the objectives, although I also discovered that the steel clips holding the prisms in place had rusted significantly over time. I did not attempt to clean the clips, as I judged that doing so might throw the instrument out of collimation.

Note the rusted steel clip holding one of the prisms in place, as well as the anti-reflection coating of the second prism(after cleaning).

The objectives on the Jenoptem after cleaning. Note the anti-reflection coatings.

Seen in broad daylight, I was able to verify that the lens coatings had not suffered much in the way of wearing, looking smooth and evenly applied, giving a bluish or purple cast, depending on the angle of view.

The appearance of the objectives in broad daylight after cleaning.


And the ocular lenses.

Optical tests:

After screwing the objective modules back into place, I was now ready to begin my optical tests of this older Zeiss binocular. I compared the views served up by this instrument with those garnered by my Barr & Stroud 10 x 50 Sierra roof prism binocular that I use almost exclusively for astronomical viewing. After setting the right eye dioptre on the Zeiss to suit my own eyes, I started with an iphone torch test to assess how the instruments fared in suppressing glare and internal reflections.

The Zeiss 10x 50W Jenoptem(right) and my Barr & Stroud 10x 50 Sierra roof prism binocular(left).

Because the Zeiss does not have the same close focus (~2m) performance as my Barr & Stroud, I had to place my iphone torch several metres away in my hallway in order to get the Zeiss to focus on its light. As usual, the torch was adjusted to its highest (read brightest) setting. Comparing the two in-focus images, I could see that the Zeiss fared considerably worse than the Barr & Stroud. Specifically, it picked up two fairly bright internal reflections, as well as quite a lot of contrast-robbing diffused light, which rendered the Zeiss image considerably less clean and contrasted in comparison to my control binocular. The difference was quite striking!

After dark, I aimed the binoculars at a bright sodium street lamp and again compared the images served up in both instruments. As expected, the Zeiss showed much more in the way of internal reflections, with a lot of diffused light that produced a fog-like veil around the street lamp. The Sierra 10 x 50 in comparison served up a much more ‘punchy’ image with much better control of internal reflections and far less of the foggy, diffused light evidenced in the Zeiss.

Next, I compared the Zeiss and the Barr & Stroud Sierra on a daylight test, examining a tree trunk in the swing park about 80 yards from my front door. Again, the difference between both instruments was striking! Although the image was very sharp in the Zeiss at the centre of the field, it was noticeably dimmer than the Sierra. That diffused light I picked up in the iphone torch test created a foggy veil that significantly reduced its contrast in comparison to the control binocular. I was also able to discern many more low contrast details in the Sierra owing to its ability to gather significantly more light than the older Zeiss. The colour cast presented by both binoculars was also noteworthy. The Zeiss threw up quite a strong yellowish colour cast  to the Sierra, which showed a much more neutral cast in comparison.

Examining the periphery of the same field also showed that the Sierra was exhibiting a larger depth of focus than the Zeiss, which was quite unexpected, as I had been given to understand that porro prism binoculars in general show more depth of focus than their roof prism counterparts. In addition, the Zeiss showed more distortion at the edges of the field than the control binocular.

The Zeiss Jenoptem has very tight eye relief, which I estimated to be just 10mm. The Barr & Stroud Sierra, in contrast, has much more generous eye relief in comparison- 17mm – making it significantly more suitable for eye glass wearers. Indeed, I found it difficult to image the entire field in the Zeiss, having to move my eyeball around to see the field stops.

In summary, these daylight tests clearly showed that the venerable Zeiss was no match optically for the Barr & Stroud 10 x 50 roof prism I had tested it against. The latter was simply in a different league to the former, no question about it!

Handling in the Field:

The Zeiss is rather big and clunky in my small hands and is more difficult to find that optimal position while viewing for extended periods. Weighing more than 200g more than the Sierra, it is also harder to hold steady. The significantly smaller frame of the Sierra roof prism binocular is much easier to negotiate, and is simply more comfortable to use. In addition, the Zeiss has no provision to mount it on a lightweight tripod or monopod, but the Sierra, like most other modern binoculars, does.

Astronomical tests:

Though the weather proved quite unsettled during the week that I tested the Zeiss, I did get a few opportunities to test it out on the night sky. Once again, I used my Barr & Stroud Sierra 10x 50 roof prism as a suitable control. My first target was a bright, waxing gibbous Moon fairly low in the southern sky. The Zeiss threw up more in the way of internal reflections than the Sierra. The colour cast of the lunar surface appeared more yellow in  the Zeiss compared with the cleaner images of the Sierra. As I expected from my iphone torch tests, the sky immediately arround the Moon was also brighter in the Zeiss, with noticeably lower contrast than the Sierra. Moving the Moon to the edge of the field also showed that the Zeiss threw up more distortions than the Sierra control binocular.

Turning to Vega high in the northwest after sunset produced good on-axis images in both binoculars, but when moved to the edge of the field, the Zeiss threw up that little bit more distortion than the Barr & Stroud Sierra. The same was true when I examined the Pleaides and the Hyades in Taurus.

Conclusions and Implications:

The Zeiss Jenoptem was a good binocular in its day but is clearly inferior in almost every sense to the Barr & Stroud roof binocular used in comparison. 40 years ago, the Zenoptem would have set the average factory worker a whole month’s salary to acquire new. In contrast, the Barr & Stroud Sierra can be had for between £100 and £120 in today’s market.  The value of waterproofing was made manifest in the observation of rusting of some of the metal internal components of the Zeiss. The Sierra, in contrast, is fully waterproof, o-ring sealed and purged with dry nitrogen gas to inhibit internal fogging and corrosion of any metallic components used in its construction.

Enormous advances in optical technology over the last four decades, particularly full broadband multi-coatings applied to all lens and prism surfaces, higher quality optical glass, as well as phase coated prisms on the roof binocular, collectively allow very efficient light transmissions to the eye. This is all the more remarkable since roof prism designs usually have many more optical components than their porro prism counterparts.

Better eregonomics in modern roof prism binoculars as well the employment of strong, low mass polycarbonate housings in their design make them lighter and easier to use than their porro prism counterparts from a generation ago. All of these add to the comfort of using them either during the day or at night when looking at the heavens.

I had a look on ebay to see what these old Jenoptems were being offered for. I found quite a few of them selling for between £150 and £200, so not the high prices demanded by other classic binoculars.

Like with all optical firms, time has marched on, with modern binoculars offering much better performance than earlier models.

This comparison test must have implications for many people who already own or use older binoculars and who have not compared them to modern incarnations. And that’s as true for Zeiss as with any other manufacturer. Indeed, I was quite shocked at how much better my first quality roof prism 8 x 42 roof prism binocular fared compared to an old 7x 50 porro I was gifted back in the early 1990s. Technology has well and truly marched on! And while I like classic instruments just as much as the next guy, I see little point in using any when even modest instruments created in the modern age are likely to perform better than similar instruments made a generation ago. It’s just a hard fact of life.

The technology of the past is certainly interesting but it would be daft to neglect the advances offered in the modern era.


I would like to extend my thanks to Sandy and his parents for allowing me to test drive these old binoculars. I will be advising him to use lens caps on the optics when not in use and have also provided a sachet of silica gel dessicant to minimise moisture-induced corrosion of the optic.


Neil English discusses all manner of classic telescope technology in his 650+ page historical work, Chronicling the Golden Age of Astronomy(Springer-Nature).


De Fideli.

A Magical Hour with my 130mm F/5 Newtonian.

A grab ‘n’ go telescope on steroids.

Anno Domini MMXIX

My conversion to Newtonian telescopes continues apace. Though I’ve had my wonderful 130mm f/5 Newtonian travel ‘scope for a few years now, it never ceases to impress me. And my observations on the freezing night of November 18 with the same instrument only served to consolidate those sentiments.

I set the telescope out on its trusty Vixen Porta II alt-azimuth mount about 10.30pm local time and tweaked its collimation before leaving it to cool down from an indoor temperature of 20C to an outside temperature of -5C. The optical tube is quite rigid and it holds accurate collimation very well, which is fine for general observing, but I always fine-tune the alignment of its two mirrors when going after the tightest double stars. I knew conditions would be good for such an activity by noting how little Vega was twinkling low down in the western sky, while bright stars like Capella and Mirfak located high overhead shone with a steady, planet-like gleam.

The tube is insulated with a thin layer of cork and overlaid by black flocking material. I have noted that this affords extra thermal stability to the telescope, especially as temperatures drop rapidly(as occurs during acclimation on these cold nights). I do not use any air-blowing fans to accelerate cooling of the primary mirror, but this has never really been an issue with this small Newtonian telescope.

After enjoying a lengthy binocular session using my 20 x 60 on a simple monopod, I began an hour of telescopic observations on a number of seasonal double stars, beginning about 11:20pm. Orion was quite well placed  east of the merdian, so I inserted my Meade 5.5mm UWA yielding 118x on a fairly low lying Rigel, carefully focused and observed the stellar image. Wow! What an amazing apparition! I was greeted by an intensely bright image of this white supergiant star, with beautiful diffraction spikes radiating outwards from a calm Airy disk. And just a little to its southwest, its faint close-in companion was easily discerned. That was enough of a confirmation that seeing conditions were indeed very good, so from there I panned the telescope northward to the better placed belt stars of Orion, examining both Mintaka and Alnitak at the same power. The images of both stellar systems were lovely and calm, with beautiful hard Airy disks betraying their companions with ease.

From there, I moved up to a more challenging system, 32 Orionis, located just a few degrees east-southeast of Bellatrix. Coupling a 3x achromatic Barlow lens to the Meade 5.5mm yielding a power of 354x, I carefully focused the image, watching it as it raced across the field of view. Sure enough, its close-in companion(separation ~ 1.3″) proved easy pickings for this light-weight 5.1-inch telescope situated just off to the northeast of the primary. Before leaving the celestial Hunter, I had a quick look at Eta Orionis, another fine, high-resolution target, consisting of a magnitude +3.6 primary and a tight, magnitude +4.9 secondary. Both were nicely resolved at 354x, and roughly orientated east-to-west.

Pointing the telescope at majestic Auriga, now very high in the sky, I trained the instrument at Theta, an old friend, and backed the magnification down to 236x by swopping out my 3x Barlow for a 2x Orion Shorty. That was more than enough to resolve its ghostly companion in the still midnight air.

I spent the next quarter hour exploring some favourite doubles in Cassiopeia, notably the lovely colour contrast pair, Eta Cassiopeiae, admiring the textbook perfect images of its yellow primary and ruddy secondary at 118x. And from there I moved to Iota Cassiopeiae, beholding this beautiful triple system at 236x. These views inspired me to swing the instrument westward into Andromeda, where I quickly tracked down another binary superstar, Almach, where the telescope showed me a gorgeous, crisp image of the orange primary and widely separated blue secondary at 118x.

After a quick look at Castor A, B and C at 118x, I trained my eyes on Propus, the ‘orange nemesis,’ as I have come to call it, which by now was reasonably well placed but still a few hours from culminating in the south. This system requires very high powers, so I broke out my 4.8mm T1 Nagler and coupled it to my 3x Barlow lens, delivering a magnification of 405 diameters. Carefully focussing the star, I watched it cross the field of view several times, observing its behaviour at this ultra-high power. During some moments, the system swelled up to become a rather unsightly seeing disk owing to a combination of thermal stress and variations in seeing, but sure enough, there was always prolonged moments where the image came together, as it were, allowing me to carefully examine the stable Airy disk. And it wasn’t long before I began to see the little blue pimple of light from its tiny secondary touching the marmalde orange primary. Having examined this system quite a few times with the 130mm Newtonian over the last few years, I have learned that good seeing doesn’t always yield commensurately good results. This I attribute to the slightly variable nature of this post-main sequence star, which can often hide the companion. But tonight, my patience paid off!

Plotina: strutting her stuff at -5C.

I ended the vigil shortly before half past midnight local time, by moving the telescope from my back garden to the front of the house, where I was greeted by the light of a silvery last quarter Moon, hanging above the Fintry Hills to the east. Inserting the little 4.8mm Nagler delivering 135x, I enjoyed some wonderful, crisp images of the battered lunar regolith, particularly the majestic Apennine Mountains strewn across its mid-section, near the terminator, as well as the magnificent desolation of the heavily cratered southern lunar highlands.

Simple pleasures of a telescope.

It was good to get out. But it was equally nice to retire the telescope indoors and reflect on the experience, sat next to a warm coal fire.



De Fideli.




Return to Wigtown: October 2019.

The driveway up to East Kirkland Farm, Wigtown.

Our annual family October vacation almost never happened this year. Our car gave up the ghost, necessitating the purchase of a new one just a week before our planned trip, and then, to add insult to injury, our fan oven died, requiring us to pay out still more cash to get it replaced. Luckily, I had just received an advance on my new book, as well as my first pay cheque for my debut feature-length article in Salvo Magazine, outlining the scientific case against extraterrestrial life.  Unfortunately, the holiday cottages at East Kirkland Farm were almost fully booked by the time we made our enquiries, and all the proprietors could offer us was a few days, starting on Wednesday October 16 until the end of the week. Trying to salvage some quality time away, we jumped at the chance and decided to go for it!

This was our fourth trip down to Wigtown, located at the very southwest tip of Scotland. As I have documented in previous blogs, I have enjoyed some beautiful, pristine skies here in the past, using a variety of hand-held binoculars and telescopes . What I mainly wish to report here is one night of observations, which took place at East Kirkland on Wednesday, October 16 2019.

I took along my trusty, high-performance 130mm F/5 travel Newtonian reflector in its padded aluminium case and my new pocket binocular; a Zeiss Terra ED pocket 8 x 25mm, for daylight observations of the landscape. I elected not to take my larger binoculars as there was a bright, nearly full Moon in the sky, which would rise early in the evening making observations with larger binoculars almost impossible to conduct. No, I would be using the Newtonian to carry out some observations of a suite of double stars, both easy and some more challenging, as these are largely unaffected by the presence of a bright Moon.

Two wonderful travelling companions.

After driving through an active weather system in the morning, the skies cleared as we approached Wigtown and the afternoon turned out to be sunny and reasonably warm, with only a few clouds in the sky.  After unpacking, I set up the 130mm on my old Vixen Porta II alt-azimuth mount in the shade of a garden tree where I was able to enjoy wonderful, ultra-high-powered views of the hinterland. As I expained in previous blogs, this little Newtonian is an excellent spotting ‘scope, possessing  superior light grasp and constrast that easily exceeds the performance of conventional spotting ‘scopes that often cost considerably more. This is especially apparent in low light conditions that are all too common during the shorter days of late autumn and winter.  Alas, I didn’t bring along my Vixen erecting lens but I didn’t really need it. I just drank up the views at 118x of tree trunks and branches, golden autumn leaves and bramble bushes, still drenched by the rainfall that occurred that same morning,  just a few tens of yards away in the distance. Indeed, of all the kinds of optical equipment now availalble to the nature lover, conventional spotting ‘scopes make little sense to me. Why fork out so much for an instrument that is severely limited by its small (70-100mm) aperture?

Plotina, my wonderful 130mm f/5 travel Newtonian delivering some ultra-high powers of the terrestrial creation on the afternoon of October 16, 2019.

The evening remained largely cloud free but I knew that a nearly full Moon would be rising early in the east, at about 7.30pm local time. Conditions were quite different to the other occasions I have observed here in past journeys. This time, there was hardly any wind all day and the evening brought some high altitude cirrus cloud and lower altitude cumulus that came and went as the evening dragged on. Still, a quick look at Delta Cygni showed that conditions were, once again, excellent(Ant I-II). The faint companion was steadily seen and observed at 354x (Meade Series 5000 UWA coupled to a 3x Meade achromatic Barlow). The Airy disks were tiny and round with a single, delicate diffraction ring surrounding the bright primary.

Moonrise over Wigtown, as captured at 20:58 h on Wednesday October 16, 2019.

During our summer trip to Pembrokeshire, South Wales, I forgot to bring my flexi-dew shield, which forced me to adopt a totally different strategy while observing. Thankfully, the dew shield came with me this time and it proved indispensable as these calm conditions would bring a heavy dew.

I really got stuck in after supper, just after 8pm local time, visiting a suite of favourite double and multiple stars witth Plotina. Albireo in Cygnus was mesmerizing with lovely calm Airy disks displaying their true colours(the reflector afterall is a true achromatic telescope) in the telescope at 118x. Moving over to Mu Cygni, I cranked up the power to 354x to cleanly resolve the two close companions and a bright field star wide away. Moving into Lyra, I got a text-book perfect split of the four components of Epsilon 1 & 2 Lyrae at 118x but an altogether more satisfying split at 270x (4.8 mm T1 Nagler coupled to a 2x Orion Shorty Barlow) . And to give the reader an idea of how good the skies were here at this time, I was able to cleanly split Epsilon Bootis at 118x and 135x, even though it was very low in the western sky at the time of observation!

Moving to the southwest sky, I turned the little Newtonian on Pi Aquliae and was rewarded by a very crisp splitting of this near-equal brightness pair at 354x. I then moved the telescope on Polaris, the pole star and enjoyed a lovely calm view of its very faint companion at 118x. The same was true of Mizar & Alcor, which  presented a downright dazzling light show in the telescope at 118x.

By 9pm, Cassiopeia was well positioned high in the sky and I turned the telescope to another system, that up to relatively recently was considered tricky by dyed in the wool refractor nuts. I speak of course of Iota Cassiopeiae, which was easily resolved into its three components at 118x. The view was far more compelling at 354x though! From there, I panned the telescope across to Eta Cassiopeiae, where the telescope presented a beautiful, ruddy primary and yellow secondary some three magnitudes fainter(magnitude +7.5)

At about 9.30pm local time, I turned the telescope on another autumn favourite; Almach; which presented gloriously with its orange and bluish components in the Newtonian at 118x and 354x. Finally, I tracked down another very close system, 36 Andromedae, a 1.0″ near equal brightness pair. Centring it in the field of view using the slow motion controls on the Vixen Porta II mount, I cranked up the power to 354x to behold a wonderful sight; two tiny Airy disks with a sliver of dark sky between the components! Reaching for the 4.8mm Nagler, and coupling it to my 3x achromatic Barlow lens, the power was increased to 405x, where I was still able to stably hold both components as they raced across the field of view from east to west.

Some folk might form the erroneous view that these conditions must be rare in the British Isles, but I have conclusively de-bunked that opinion(promulgated by lazy, arm-chair amateurs unwilling to do any field work of this nature). There are, in fact, many places in Britain and Ireland which give the same kind of excellent performance with this little Newtonian reflector. So, it has nothing to do with sheer dumb luck, but all to do with diligent enquiry!

The next day, October 17, proved a washout, unfortunately. Frequent heavy showers of rain put a severe dampener on the vacation and these showers persisted right into the early and late evening, so I didn’t bother to use the telescope. That said, I have one additional memorable observation to report during the wee small hours of October 18. Sticking my head out of doors at 1.20 am local time showed a bright waxing Gibbous Moon skirting very close to the bright star, Aldebaran. Reaching for my little Zeiss Terra pocket binocular showed me a most arresting sight! The Moon was just a few degrees directly east of the horns of Taurus, looking for all the world as if it were about to lock horns with the celestial bull. I watched in sheer amazement as some clouds blew across the Moon from west to east, blotting out some of the glory of the stars of the Hyades, but in the process, creating a wonderful display of light and colour, as the low-altitude rain clouds approached and then receded from our bright, natural satellite. I only wished I had brought along my 8 x 42 Savannah binocular to capture still brighter images of this marvellous apparition, but hindsight is indeed a wonderful thing!

It would have been nice to have another night to accumulate more data at this site but it was not to be. Still, it was good to get away, if only for a few days.

A capital grab ‘n’ go telescope. Powered by human muscle, eyes and brains.

I would continue to encourage others who have a small Newtonian telescope like this to perform their own field tests on these and other double stars. I mean, it’s all very easy to falsify, isn’t it? You just need to collimate accurately and allow enough time for the telescope to acclimate fully to the outside air. That said, If time is against you,  it’s best to start with the easiest pairs and move onto the tighter ones as the telescope nears full equilibration.

Good luck with your adventures!

Neil English is the author of seven  books. His largest work, Chronicling the Golden Age of Astronomy, provides a historical overview of many astronomers from yesteryear who used Newtonian reflectors productively in their exploration of the heavens.


De Fideli.

The Field of Glory.

Companion under the stars: the Pentax PCF 20 x 60 binocular.


Visual astronomy can be enjoyed in a variety of ways. We can use the eyes our Creator designed for us to marvel at the beauty of the night sky. Or we can employ a telescope to get those up-close views, where both resolving and light gathering power are needed to make sense of what we see. But there is also the binocular perspective, which fills a niche set midway between that of the eye and that of the telescope.

On the night of August 25 2019, I found myself doing all three. After an hour of admiring dim and hard to find deep sky objects using my largest telescope; a 12″ f/5 Newtonian reflector, I sat back in my observing chair to drink up the naked eye heavens above me. The air was still, with no wind, and only the occasional screech of a barn owl breaking the silence. After a few months of twilit skies with only the brightest stellar luminaries on display, true darkness had now returned to the landscape. By 11:30pm local time, the bright constellations of Cygnus, Lyra, Hercules and Aquila had passed into the western hemisphere, with Bootes now sinking perilously close to the western horizon. And over in the northeast, Cassiopeia, Perseus and Auriga were making excellent progress climbing ever higher in the sky.  Andromeda and Pegasus were also ripe for exploration. The familiar asterism of the Plough hung low over the northern horizon, far below the North Star, Polaris, around which the great dome of the sky wheels. With no Moon in the sky, and good transparency, the river of light from the northern Milky Way stood out boldly, snaking its way across the heavens from east to west. It was the perfect opportunity to break out my big binocular, a Pentax DCF 20 x 60 and boy did it deliver the readies!

Using a monopod for big binocular astronomy on the go.

As I described at great length in the preamble linked to at the beginning of this blog, the Pentax DCF 20 x 60 combines excellent optics with great mechanical features in a relatively light weight package; ideal for use with a monopod. The instrument attaches in seconds to a strong, high-quality ball and socket mount head and can be transported easily from one place to another. Delivering a pristine, flat field some 2.2 degrees wide, the Pentax had already delivered gorgeous views of the heavens during Winter and Spring evenings, but I had not yet had an opportunity to sample the skies of late Summer/early Autumn with this powerful optical instrument.

My first target was M13, easily found about one third of the way from Eta Herculis to Zeta Herculis in the western edge of the famous Keystone asterism. I had already admired this big and bright globular cluster earlier in the 12″ telescope at high power. The 20 x 60 binocular revealed a bright fuzzy bauble about half the size of the full Moon and neatly sandwiched between two 7th magnitude field stars. Of course, the binocular could not compete with the majesty of such a cluster as presented in a large, light bucket, but it was nonetheless a lovely sight with wonderful contrast against a jet black sky.

I then moved over to Lyra and centered the bright summer luminary, Vega, shining with its intense blue-white hue across the sea of interstellar space, and surrounding it a swarm of fainter suns, including the famous Epsilon Lyrae of double star fame. Moving into Cygnus, I turned the binocular on Beta Cygni, known more commonly as Albireo. With a steady hand, I could easily resolve the beautiful, wide colour contrast double star; marmalade orange and blue-green secondary. Panning about eight degrees due south of Albireo the binocular field soon captured that remarkable little asterism that is the Coathanger (Collinder 339). What makes this a particualrly engaging visual sight is the uniformity of the stars comprising it; most shining with a soft white hue and of the sixth magnitude of glory.

Moving about five degrees to the east of the Coathanger, and forming a neat little right-angled triangle with the stars of Saggita, the celestial Arrow, I chanced upon the large and bright planetary nebula, known commonly as the Dumbbell (Messier 27). Unlike other planetary nebula, M27 is one of the few that present clearly in the relatively low power view of the binocular. Try as I might though, I could not see the hourglass shape of the nebula as seen in telescopes at higher power; it was more or less circular in form, softly glowing against the background sky at magntude 7.4.

I didn’t have to travel far for my next visual treat; M71, a faint globular cluster situated nearly exactly midway between Gamma and Zeta Saggitae. With its population of mostly 12th magnitude suns, M71 presented as a misty patch in a glittering hinterland of August star light.

Adjusting the ball & socket head of the monopod, I ventured back into Cgynus and centred the lovely binocular double,  commonly referred to as 0^1 Cygni. Like a wider version of Albireo, the 20 x 60 binocular presented their fetching colours perfectly, orange and turquoise (magnitude 3.8 and 4.8, resepctively). I could not however clearly resolve the fainter 7th magnitude component parked up against the orange member, which a small telescope so easily shows.

Eager to examine another stellar hinterland, I moved the binocular so that Deneb was centred in the field of view. Well, this binocular portal took my breath away! Hundreds of suns of varying degrees of glory smattered haphazardly across the field, and here and there the excellent contrast of the instrument also showed up some small nebulous patches set adrift among the starry hosts. With its very generous 21mm of eye relief, the big binocular was delivering very comfortable and immersive views. It was almost as if I could reach out my hand and touch the heavens!

With midnight approaching, I noticed that the great square of Pegasus was clearing the rooftop of my house, and a little further to the east, Andromeda, the Chained Lady, had by now gained a decent altitude. Eagerly, I trained the binocular on a foggy patch clearly seen with the naked eye. I had arrived at the Great Andromeda Galaxy (M31). The lenticular shaped core was big and bright and beautifully contrasted against a sable sky, and with averted vision it was not hard to trace the spiral arms all the way to the edges of the field. Its fainter companions, M32 and M110, were also seen with a concentrated gaze, the former being easier to see and just a half an angular degree to the south of M31. M110 proved much more elusive though, being larger and fainter than M32 but nonetheless fairly easy to pick off about a degree away to the northwest of the main galaxy.

Moving into Cassiopeia, the binocular presented field after field of brilliant starlight with a wonderful variety of colours. Many faint open clusters came to life as I inched the binocular through its mid-section; NGC 457(otherwise known as the E.T. Cluster) was very engaging, especially the bright, 5th magnitude white super-giant star marking its southern border, and then on into the heart of M103, a compact little open cluster just to the northeast of blue-white Delta Cassiopeiae. My notes from a good few years back informed me that the cluster presented as unresolved in an inexpensive 15 x 70 binocular, but this instrument, with its significantly higher magnification, was just beginning to hint at some individual stars within the cluster. A comely quartet of stars flanking the southeastern corner of the Messier cluster made the scene especially engaging to study. Panning very slowly eastward through the constellation, roughly from Delta to Epsilon Cassiopeiae, my eyes picked up many faint open clusters, including NGC 44, 663, 559 and 637.

By about a quarter past midnight, Perseus had risen to a good height above the northeastern horizon, and I eagerly sought out the famous Double Cluster(Caldwell 14), easily located as a foggy patch to the naked eye roughly mid-way between Perseus and Cassiopeia. With great excitement, I moved in on my target, all the while bringing to mind the stunning views I had reported with this binocular last Winter. Wow! I wasn’t disaapointed. The entire field exploded with stars of various hues; white, blue-white, creamy yellow and sanguine, the two sumptuous open clusters beautifully resolved with curious fans of stars radiating outwards from their centres. Sharpness was extreme from edge to edge, with the stars presenting as tiny pinpoints. I believe that this 20 x 60 binocular renders these awesome natural spectacles as good as you’ll ever see them; the combination of decent light gathering power and magnification using both eyes is a match made in heaven! This was a pre-season teaser though. The Double Cluster will only increase in majesty, as it continues to climb higher in our skies over the next few months.

Moving to Algol, the Demon Star, I then navigated about 5 degrees west from it, where I was pleasantly surprised by how easily I was able to pick up another lovely open cluster, M34. The powerful double eye on the sky resolved a few dozen members, mostly 7th, 8th and 9th magnitude members sprawled across an area of sky roughly the size of the full Moon. Many fainter members, largely unsresolved by the instrument, gave the cluster a very lively, translucent appearance, a consequence I suppose of the inability of the binocular to cleanly resolve its faintest members, which go all the way down to magnitude 13. Sometimes, not seeing things clearly adds to the visual appeal of deep sky objects.

From there, I moved back to Alpha Persei and placed it at the upper edge of the field of view of the 20 x 60. Even though the binocular has a fairly restricted 2.2 degree true field, it was able to pick up a generous assortment of bright O-B stars at the heart of the moving cluster Melotte 20. It was a beautiful sight!

With the time fast approaching 12:30 am, I picked up the 20 x 60 astride its monopod and moved to the front of the house, where my gaze met with the Pleiades rising above the Fintry Hills to the east of my home. Though it was still at a fairly low altitude, the 20 x 60 produced a draw-jopping view of this celebrated open cluster, its orientation being rather lobsided compared with how it appears later in the autumn. Many of its fainter members were extinguished by virtue of its low altitude, but it was still a magnificent sight. Again I would concede that large binoculars produce the best views of the Pleiads. And it will get better, night by night, as Autumn turns to Winter.

With a waning crescent Moon not far away from rising, I retired from the field of glory with a head full of vivid memories. This was just the beginning though. God willing, it will show me even grander sights as the days continue to shorten through the autumnal equinox and onwards toward the December Solstice.


Neil English’s new book, The ShortTube 80, A User’s Guide, will soon be published by Springer-Nature.



De Fideli.

Exploring the Skies Over Rural Pembrokeshire.

Slova Beach, Pembrokeshire, Wales.

De omnibus dubitandum



Results from Northwest, Central and Southwest Scotland

Results from Central Scotland

Results from Northwest England

Results from the Republic of Ireland

5″ f/12 refractor versus 130mm F/5 Newtonian Shootout

Investigating the Jet Stream


Wales is a country of outstanding natural beauty, with deep valleys, high mountains and rolling hills. Its rugged coastline boasts many pristine(blue flag) beaches and pretty little towns that are a joy to visit and explore. Like Scotland, frequent weather systems move in from the Irish Sea, purging the air of particulates that create excellent transparency for remote daytime viewing and astronomical adventures when the Sun sinks beneath the horizon.

Newgale, Pembrokeshire.

We decided on Wales because my brother and his young family had moved there last year from northeast Scotland, where he settled in a large country house dating from the mid-19th century, situated on the outskirts of the small village of Letterston, some ten miles north of Haverfordwest and 6 miles inland from Fishguard, where you can catch a ferry across the open sea to Ireland. And besides, we’d never vacationed in Wales before, so we had no good excuse but to make that 400 mile journey south from our home in rural, central Scotland.

St. David’s Cathedral, a place of worship since the 6th century AD. From the City of St. David’s, Pembrokeshire, southwest Wales.

The house is situated on five acres of choice land, secluded on all sides by woody glades, and even sports a large fish pond fed by a couple of fresh streams meandering through the estate. The homestead is surrounded by beautifully tended lawns and flower gardens that thrive because of frequent rain showers which keep them lush and well watered. It is a very peaceful place, with little in the way of light pollution, save for the glow from Haverfordwest, which illumines the southern horizon. Higher up though, the night sky is truly glorious, where the summer Milky Way winds its way from Perseus in the northeast to Sagittarius in the south.

Lower Summerhill.

We arrived late on Monday July 29, after spending much of the day travelling. I was glad that night was rainy and overcast, as I was exhausted from the journey and in no mood to pull out a telescope. Besides, we were all eager to catch up with my brother and sister-in-law, and my boys stayed up well beyond their bed times nattering to their first cousins. The next night was overcast but remained dry.

But the next three evenings were clear.

The sojourner: Plotina, the author’s nifty 130mm f/5 Newtonian reflector. The pond lies in the background.

I brought along my portable 130mm f/5 reflecting telescope, which had proven to be spectacularly successful in ‘scouting out’ good sights to view the heavens from. It had already travelled a few thousand miles all around Britan and Ireland, where I had tested the skies on a number of choice double stars to establish something of the seeing conditions across the British Isles, some of which are highlighted in the links provided above.

As I have communicated many times in the past, this little Newtonian had greatly exceeded my expectations. Sporting a high-quality 5.1″ primary mirror and an upgraded secondary, when cooled and collimated, had shown me arguably some of the best views I have ever experienced with any grab ‘n’ ‘scope. With its state-of-the-art reflective coatings and modest( 26.9 per cent) central obstruction, it has consistently delivered the readies in all weather conditions, from warm, muggy summer nights to freezing winter evenings. It has proven itself to be a first rate double star ‘scope, which, under the right conditions, renders beautiful, colour-pure images of the Creation. Three eyepieces attended the instrument in its foam-lined aluminium case; a 25mm Celestron X-Cel LX, delivering a power of 26x in a well corrected 2.3 degree true field. This is my favourite wide-field scanning ocular used with the 130mm, great for observing star clusters and large deep sky objects. For medium power work, I brought along my Parks Gold 7.5mm, a delightfully simple eyepiece with wonderful contrast. Coupled to a 3x Barlow it delivers a power of 260x, which is a good working magnification to use on a variety of closer doubles. For higher power work, I also took along my Meade 5.5mm Ultra Wide Angle(UWA), delivering a power of 118x in a true field of ~ 0.7 angular degrees, useful for close up observations of smaller deep sky objects. And when coupled to the 3x Barlow yields a power of 354x, great for ferreting out the most difficult pairs. Still, it must be mentioned that this instrument can handle 100x per inch of aperture, if push comes to shove.

Beach Gear

The only other instrument I took along with me was my Pentax 9 x 28mm DCF LV roof prism binocular. I figured I would get a lot of use out of this, as we planned to visit many places where they would come in handy. I had intended to bring by trusty 8 x 42 but these had to be sent away for repair/replacement. And although the small Pentax binocular was the perfect accompaniment by day, I regretted not bringing my 10 x 50 roofs. Indeed, I really ought to have brought along both instruments with me.

Conditions at the site:

Dusk, looking westward.

Being located so close to the coast, the evenings are often breezy from onshore winds, but by dusk, they usually abate, creating very tranquil conditions. What I also noticed was how quickly and heavy the dew is at this site; significantly more aggressive than at home. Indeed, my observing sessions were limited by dew, as the telescope has no fans or dew heaters to keep it at bay. And I had forgotten to take along my flexi dew shield, so unfortunately, it was always a race against time.

I encountered no midge flies while making observations; a God send! They’d eat you alive in Scotland!! What you can get here is horse flies though. Thankfully they left me alone throughout the vigils.

Session 1: July 31 2019

The first object to emerge from the dusk was mighty Jupiter, appearing ever more bright as the twilight gave way to proper darkness and a few degrees higher in the sky than it appears up in Scotland.. Beginning around 20:55UT, I charged the telescope with the 5.5mm Meade UWA yielding 118x, and turning it on the giant planet, I was greeted with a very nice image. All four Galilean satellites were visible, a couple to the east of the planet and a couple to its west. The planet itself was revealing some very fine details, several tan-coloured bands and bright zones. The north equatorial belt was very prominent but its southern counterpart showing visible disjointing. 118x was producing a nice image scale, plenty high enough to see fine detail but not so enlarged as to wash out the same details. It was nice to greet an old friend like this. Its lower altitude back home had often blurred these finer details so much that I had all but abandoned the planet during this current apparition, holding out for better conditions when the planet gains altitude in a few years from now.

Studying the giant planet for a few minutes also suggested to me that the seeing was going to be good for double star testing, and lo, it most certainly was!

21:03 UT: Epsilon Lyrae 1& 2; beautifully resolved into four components at 260x

21:06 UT: Epsilon Bootis; text book perfect rendition of this gorgeous colour-contrast double. Beautifully rendered at 260x

21:10UT: Delta Cygni; textbook perfect split of this system with its bright primary and faint secondary. Easy picking at 260x

21:15 UT: Finder scope had already dewed up, so I detached it from the ‘scope, capped up the main telescope and brought the finder indoors to let the condensation evaporate.

21:57 UT: Resumed observations of double stars, starting with Pi Aquilae, which was very easily split at 354x

21:29UT Lambda Cygni: a sub-arc second pair. Airy disks touching at 354x but not cleanly disjointed.

21:31UT: Mu Cygni, easy split at 260x

21:50UT I turned back to Jupiter and immediately noticed the Great Red Spot (GRS) near the eastern limb. Even finer planetary details were coming through now in the darkened sky. I decided to cap up the optics on the main ‘scope once again to ward off dew, removed the finder scope and brought it indoors. This would be a good opportunity to make a measurement of the current Central Meridian (CM) II longitude of the GRS.

I re-emerged from indoors at 22:20 UT, uncovered the 130mm’s optics and re-mounted the finderscope. Aiming once again at Jove, the GRS had moved considerably further west but was not yet at the central meridian. Over the next twenty minutes I watched carefully using the Meade 5.5mm UWA(118x) throughout and was finally satisfied that the GRS was on the CM II meridian at 22:41UT.

I had to wait until I returned home to turn this timing into a CM II longitude for the GRS. Downloading the latest edition of WinJupos freeware, I entered the longitude, latitude and time I estimated the spot was crossing the meridian( 22:41 UT). The software computed a value of 312.4 degrees:

WinJupos computation of the GRS transit across central meridian.

I then searched to find a reliable source that quoted the most up-to-date CM II longitude determination of the GRS and found this recent(as of June 5 2019) posting on the Sky & Telescope website. See here for interest. The source quoted a value of 308 degrees!

That’s very close to the measurement I made!

Cool or what?

No’ bad,………ken.

Yessiree, the 130mm is a fine planetary telescope, allowing me to make some pretty challenging measurements more or less routinely.


Vigil ended at 22:50UT owing to build up of dew on the telescope’s secondary mirror.


A Curious Aside: Oculus Historiae


Session 2: August 1 2019

The second night was, to all intents and purposes, a carbon copy of the night before; a windy early evening which gave way to tranquil conditions as sunset approached. Starting at dusk around 21:00 UT, I set the telescope up on its Vixen Porta II mount and lowered the tripod legs a little to enable the kids to get a decent look at the two bright planets that were quite prominently on display low in the south: Jupiter and, several degrees further east, majestic Saturn. Keeping the magnification at 118x, the telescope displayed crisp views of both worlds, but alas, no sign of the GRS. My boys had seen these worlds before, of course, but not their cousins.The twins(Luca & Amabelle) were gobsmacked with the sight of Saturn, in particular, through the telescope. It was the first time they had ever seen this world ‘live.’ They chuckled among themselves saying, ” it’s just like you see in a book!”

Spying Jupiter and Saturn through the 130mm Newtonian. From left to right: Luca, Amabelle, Oscar and Douglas.

Well maybe, but the instrument was able to cleary show the Cassini Division as well as some subtle banding on this giant world 880 million miles away! I judged the image to be very good considering its woefully low altitude.Like Jupiter, it promises to yield better views for us far-northern observers in the years ahead.

A little later, my sister-in-law, Rhiannon, came to have a look at the planets and some showpiece deep sky objects. She was amazed to discover that the instrument didn’t cost very much, even with all the modifications done to it.

Beginning at 21:15 UT,  I began my double star tests, in rapid succession, and using the same magnifications I had used the previous evening. And the results were exactly the same: very good seeing conditions, enabling high resolution double star work to be conducted.

I then took myself off to visit the Ring Nebula(M57) in Lyra, three bright globular clusters, M3 in Canes Venatici,  as well as M13 and M92 in Hercules. The good light grasp and resolving power provided very engaging views in these dark skies, which I had, by now, deemed very similar in quality to another site in Wigtown, southwest Scotland (and also near the coast!) The Whirlpool Galaxy(M51) looked great at 118x, as did M81 and M82, which were still fairly high up in the north.

I ended the telescopic vigil with quick looks at some easy multiple star gems including Mizar & Alcor, Gamma Delphini, Iota Cassiopeiae (with its 3 beautiful stellar members), Albireo and the lovely O^1 Cygni system.

The telescope had dewed up by 21:50UT, at which time it was packed up for another night.

At 22:45 UT, as every one else had retired for the night, I ventured out again with my 9 x 28 binocular, enjoying the river of starlight through the Milky Way. But what most excited me was the siight of Perseus, now set much higher in the northeastern sky. Aiming at Alpha Persei, I brought the binocular to my eyes to behold that beautiful, sprawling wonder that is Melotte 20. It’s a spectacular binocular sight, even wth this small instrument. I couldn’t help pining for something larger though, like my 8 x 42, or better still, my 10 x 50. But I suppose, we live and learn!

I retreated from the field of glory around local midnight, for we had much to do the following day.

Low tide at Solva.

Session 3: August 2 2019

Like the last two days, August 2 was warm and sunny, though today some high altitude cloud produced much more in the way of hazy conditions than on the previous days. And that haze remained into the evening and over night. As a result, transparency was much reduced to my chagrin, since I wanted to do a little bit more deep sky observing. But as any regular observer worth his or her salt will inform you, hazy conditions often portend a good, stable atmosphere. Even before commencing telescopic observations it was easy to see the conditions were excellent, with the stars twinkling even less than they had done on the previous nights.

At 21:20 UT I began with a quick look at Jupiter, now near its maximum altitude for this location, with the 130mm charged with a power of 118x. Some really fine details were showing up as the planet drifted across the field of view, proving once again that such an instrument is a good choice for observing the bright planets, especially in grab ‘n’ go mode.

At 21:30 UT, I commenced my double star observations, using the same magnifications as described on July 31, and, one by one, they all succumbed to the formidable resolving power of this telescope. Conditions this evening at this site were as good as I have seen elsewhere(Ant I); there was zero turbulence, the stars resolving to beautiful, hard Airy disks in every case. I also recorded a good split of the components of Lambda Cygni this evening, separated by 0.94″  at a power of 354x, though I would have liked to have had some additional magnifying power on this tough target( I have used 405x with this system in this telescope on many occasions).

This vigil was ended at 22:05 UT.

Conclusions: On three consecutive nights, the 130mm reflector served up excellent, high-power views of a selection of double stars, adding to my list of good places to observe from. Once again, the little Newtonian delivered the goods!

Do I attribute this to good fortune?

Sheer dumb luck?

Absolutely not!

It is the observer that creates opportunities. Diligence and determination are all that is required. The British Isles offers many places to do such work and is a far cry from the bad reputation our lands have garnered on more than a few internet forums.

Britain and Ireland are open for business and I would take any comments claiming the contrary with a large dose of scepticism.

Think tooth fairy, Yeti, Darwinian evolution…..you get my drift.

One thing is certain though; you’ll never know unless you get off your backside and do some real testing!

Memories from our trip back up north:

There were a few other nights where the skies were partially clear, allowing to me to make some short binocular tours. Indeed, the pattern was much the same as I have noted at a few other places in the UK and Ireland.

The picturesque esplanade at Aberystwyth.

We said our goodbyes to our hosts on Monday morning, August 5, when we set off northward. Our first port of call was Aberystwyth, a beautiful university town set on the coast. We enjoyed a delicious lunch, followed by a walk along its magnificent esplanade  and were sorely tempted to have a dip in the sea, but time was against us, as we had to make our way across the border into England, where we would spend a night in Liverpool.

The beach at Aberystwyth.

I’m not a fan of cities in general, but I had never visited Liverpool in all my years of living in the UK. The real reason for the visit was to do a tour of Anfield, the home ground of the 2019 Champion’s League winners, Liverpool F.C. My eldest son, Oscar, was in his element, being a die-hard Liverpool fan.

After booking into our hotel and having a bite to eat, we set off on a walk down to Liverpool docks in the late evening, taking in the amazing buildings that decorate the site,

One the amazing municipal buildings at Liverpool docklands.

Liverpool is also the ancestral home of the Beatles, and sure enough, it wasn’t long before we came across a reminder of the city’s most famous sons;

Larger than life bronze casts of the Beatles.

The city lies next to the Mersey estuary. On the evening we arrived, the tide was fully out at sunset, which made for a very pretty sight;

Sunset on the Mersey Estuary.

Taking an open-top bus around Liverpool, we learned a lot of historical information from the tour guide (speaking in broad Scouse) before being dropped off at Anfield. Countless bus loads of folk were making the pilgrimage to the home turf of one of England’s most successful football teams. I suppose for the faithful, it was like a visit to Mecca.

Anfield Stadium( August 6 2019).

The all-important silver ware.

Though we enjoyed many warm and sunny days in Wales, extending into our short trip to Liverpool, as we hit the mountains of northern England, sunshine gave way to torrential rain;

By bye to sunny skies.

Indeed, much of the rest of August brought very unsettled weather to Scotland, but at least the farmers were happy. Rumour has it that this was a record summer for growing grass and making hay! Unfortunately though, it also meant that our lawns, which were trimmed before we left, had to be cut down to size again upon our return.

Oh Bliss!

It was good to get away and spend some quality time with family. No doubt, I’ll be back again to sample its excellent skies with my little Newtonian reflector.


Neil English travels through four centuries of time to bring you many more inconvenient truths concerning the Newtonian reflector in his tome, Chronicling the Golden Age of Astronomy.


De Fideli.

Investigating the Jet Stream

but test everything; hold fast what is good.

                                                                           1 Thessalonians 5:21


My Local Weather


Jet Stream Data

Introduction:  One of the statements that is oft quoted by observers, particularly in the UK, is that the meteorological phenomenon known as the Jet Stream seriously affects the quality of high resolution telescopic targets. I have decided to investigate these claims to determine to what extent they are true or not, as the case may be. These data will also provide the reader with an idea of the frequency of nights that are available for this kind of testing over the time period the study is to be conducted.

Method: For simplicity, I shall confine my studies to just four double stars that have long been considered reasonably tricky targets for telescopists. To begin with, my targets will include systems of varying difficulty, ranging from 2.5″ to 1.5″ separation, and the aim is to establish whether or not I can resolve the components at high magnification. These systems include *:

Epsilon 1 & 2 Lyrae

Epsilon Bootis

Delta Cygni

Pi Aquilae

* These systems were chosen for their easy location in my current skies, but may be subject to change as the season(s) progress.

Viewers are warmy welcomed to conduct their own set of observations to compare and contrast results in due course.

Instrument Choice & Magnifications Employed:

The 130mm f/5 Newtonian telescope used in the present investigation.


A high-performance 130mm (5.1″) f/5 Newtonian reflector was employed to investigate the effects of this phenomenon, as this is an aperture regularly quoted as being sensitive to the vagaries of the atmosphere. Magnifications employed were 260x or 354x (they can however be resolved with less power). The instrument at all times was adequately acclimated to ambient temperatures and care was taken to ensure good collimation of the optical train. No cooling fans used on any of my instruments.


Date: August 17 2018

Time: 21:20 to 21:35 UT

Location of Jet Stream: Currently over Scotland

Conditions: Mild, 14C, very breezy, mostly cloudy with occasional clear spells, frequent light drizzle.

Observations: Power employed at the telescope 354x

Epsilon 1 & 2 Lyrae: all four components cleanly resolved.

Delta Cygni: Faint companion clearly observed during calmer moments

Epsilon Bootis: Both components clearly resolved during calmer moments.

Pi Aquilae: Slightly mushier view, but both components resolved momentarily during calmer spells.

Truth seeking.


Date: August 19 2018

Time: 20:30 – 21:50 UT

Location of Jet Stream: Currently over Scotland.

Conditions: Mild, 13C, mostly cloudy and damp all day but a clear spell occurred during the times stated above, no wind, heavy dew at end of vigil.

Observations: Seeing excellent this evening (Antoniadi I-II); textbook perfect images of all four test systems at 354x and 260x.

Nota bene: A 12″ f/5 Newtonian was also fielded to test collimation techniques and I was greeted with a magnificent split of Lambda Cygni (0.94″) at 663X. Little in the way of turbulence experienced even at these ultra-high powers. Did not test this system on the 130mm f/5.

Clouded up again shortly before 11pm local time, when the vigil was ended.

Date: August 22 2018

Time: 23:30-40 UT

Location of Jet Stream: Currently over Scotland

Conditions: Very mild (15C), breezy, predominantly cloudy with some heavy rain showers interspersed by some brief, patchy clearings.

Observations: Just two test systems examined tonight owing to extremely limited accessibility; Epsilon 1 & 2 Lyrae and Delta Cygni. Both resolved well at 260x.


Date: August 22 2018

Time: 21:00-21:25UT

Location of Jet Stream: Currently over Scotland

Conditions; partially cloudy, brisk southwesterly wind, bright Gibbous Moon culminating in the south, +10C, rather cool, transparency poor away from zenith.

Observations: The telescope was uncapped and aimed straight into the prevailing SW wind, as is my custom.

All four systems well resolved at 354x, although visibility of Pi Aql was poor owing to thin cloud covering.


Date: August 23 2018

Time: 20:30-45 UT

Location of Jet Stream: Moved well south of Scotland

Conditions: Mostly clear this evening, after enduring heavy showers all day; cool, 10C, fresh westerly breeze, good transparency.

Observations:  All four test systems beautifully resolved this evening (seeing Ant II) at 354x. Just slightly more turbulent than the excellent night of August 19 last.


Date: August 24 2018

Time: 20:30-45 UT

Location of Jet Stream: Just west of my observing site.

Conditions: Almost a carbon copy of last night, light westerly winds, cool (9C), good transparency and almost no cloud cover. Very low full Moon in south-southeast.

Observations: All four system resolved at 260x, but less well at 354x owing to slightly deteriorated seeing ( II-III). Delta Cygni seems especially sensitive to seeing.

Nota bene: Epsilon Bootis now sinking fast into the western sky. This test system will soon be replaced by a tougher target, located higher up in my skies; Mu Cygni.

A capital telescope.


Date: August 25 2018

Time: 20:20-21:00 UT

Location of Jet Stream: Right over Scotland.

Conditions: Very hazy, calm, poor transparency, cool (9C), seeing excellent (I-II)

Observations: Just three of the four systems examined tonight owing to very poor transparency. Only Pi Aquilae could not be examined. All three were beautifully resolved at 354x.


Date: August 26 2018

Time: 22:30-23:05 UT

Location of Jet Stream: Well south of Scotland.

Conditions: After a day of heavy rain, the skies cleared partially around 11pm local time. Fresh westerly breeze, fairly mild (12C), bright full Moon low in the south.

Observations: Mu Cygni observed instead of Epsilon Bootis owing to the latter’s sinking low into the western sky at the rather late time the observations were made.

Three systems well resolved ( Mu Cygni, Pi Aquliae and Epsilon 1 & 2 Lyrae) in only fair seeing, with Delta Cygni B only spotted sporadically in moments of better seeing. This system is very sensitive to atmospheric turbulence due to a large magnitude difference between components, as opposed to their angular separation. 260x used throughout.

Nota bene: Readers will take note of the frequency of observations thus far made.

Date: August 27 2018

Time: 20:30-21:05 UT

Location of Jet Stream: West of the Scottish mainland.

Conditions: Mostly cloudy, mild, 13C, light westerly breeze.

Observations: I took advantage of a few brief clear spells this evening to target my systems(including Epsilon Bootis). Seeing very good despite the cloud cover (II). All four systems easily resolved tonight at both 354x and 260x.

Date: August 29 2018

Time: 20:25-40UT

Location of Jet Stream: Not over Scotland.

Conditions: Mostly clear, occasional light shower, cool (11C), light westerly breeze, seeing and transparencyvery good (II).

Observations: Mu Cygni now replaces Epsilon Bootis.

All systems very cleanly resolved at 354x and 260x.

Nb. All systems also beautifully resolved in a 12″ f/5 Newtonian at 277x, set up alongside the 130mm f/5.


Date: August 30 2018

Time: 20:45- 21:00 UT

Location of the Jet Stream:  Not over Scotland.

Conditions: Partially cloudy with some good clear spells, cool (9C), very little breeze.

Observations: Seeing good tonight (II). All  four systems nicely resolved at 260x and 354x.

Note added in proof: Local seeing deteriorated (III-IV) somewhat between 21:00 and 22:00 UT, so much so that Delta Cygni B could no longer be seen.


Date: 31 August 2018

Time: 20:30-22:00UT

Location of Jet Stream: North of the British Isles

Conditions: Partly cloudy and becoming progressively more hazy as the vigil progressed. Mild, 12C, very light westerly breeze.

Observations: Seeing only fair this evning (II-III), all four systems resolved at 260x and 354x, though Delta Cygni B visibility was variable.


Date: September 1 2018

Time: 20:30-50UT

Location of Jet Stream: to the northwest of the Scottish Mainland.

Conditions: Partially clear, very mild (16C), light southerly breeze, good transparency.

Observations: Seeing quite good (II).  All four systems resolved at 260x and even better delineated at 354x under these clement conditions.


Date: September 4 2018

Time: 19:55-20:20UT

Location of Jet Stream: Not over Scotland.

Conditions: Cool (10C), mostly clear, light westerly breeze, good transparency.

Observations: Seeing very good (II).  All four test systems well resolved at 260x and 354x this evening.


Date: September 5 2018

Time: 20:35-20:55UT

Location of Jet Stream: Not over Scotland.

Conditions: Very unsettled with frequent squally rain showers driven in by fresh westerly winds. Good clear spells appearing between showers. Transparency very good. 12C

Observations: All four test systems resolved under good seeing conditions (II) at 260x and 354x.


Date: September 6 2018

Time: 20:00-25 UT

Location of Jet Stream: Not over Scotland.

Conditions: Cool (8C), little in the way of a breeze, mostly clear, excellent transparency.

Observations: Seeing good (II). All four test systems well resolved at 260x and 354x.


Date: September 7 2018

Time: 20:25-40UT

Location of Jet Stream: Not over Scotland.

Conditions: A capital evening in the glen; 11C, good clear sky, brisk westerly breeze, excellent transparency.

Observations: Seeing very good (I-II).  All four test systems beautifully resolved in the 130mm f/5 using powers of 260x and 354x

Nota bene:

Know thine history!

Any serious student of the history of astronomy will likely be acquainted with the early work of Sir William Herschel (Bath, southwest England), who employed extremely high powers (up to 2000x usually but actually he went as high as 6,000x on occasion) productively in his fine 6.3-inch Newtonian reflector with its speculum metal mirrors. The high powers employed by this author are thus fairly modest in comparison to those used by his great predecessor. Check out the author’s new book; Chronicling the Golden Age of Astronomy, due out in October/November 2018, for more details.

Note added in proof:

With the excellent conditions maintained well after midnight, I ventured out at about 00:00 UT,  September 8, and noted Andromeda had attained a decent altitude in the eastern sky. At 00:10UT I trained the 130mm f/5 Newtonian on 36 Andromedae for the first time this season and charged the instrument with a power of 406x. Carefully focusing, I was treated to a textbook-perfect split of the 6th magnitude Dawes classic pair that are ~1.0″ apart. It was very easy on this clement  night. The pair look decidely yellow in the little Newtonian reflector. I made a sketch of their orientation relative to the drift of the field; shown below.

36 Andromedae as seen in the wee small hours of September 8 2018 through the author’s 130mm f/5 Newtonian reflector, power 406x.


If you have a well collimated 130P kicking about why not give this system a try over the coming weeks?


Date: September 9 2018

Time: 21:10-25UT

Location of Jet Stream: Currently over Scotland

Conditions: Frequent heavy showers driven in from the Atlantic with strong gusts, 11C, some intermittent clear spells.

Observations: Seeing III. 3 systems fairly well resolved this evening. Delta Cygni B only seen intermittently. Magnification held at 260x owing to blustery conditions.

Date: September 12 2018

Time: 00:10-20UT

Location of Jet Stream: Currently over Scotland

Conditions: Very wet, windy with some sporadic clear spells, good transparency once the clouds move out of the way. 10C.

Observations: Seeing (II-III). Just three systems examined tonight; the exception being Pi Aquliae, which was not in a suitable position to observe. All three were well resolved at 260x. Did not attempt 354x owing to prevailing blustery conditions.


Date: September 12 2018

Time: 21:40-55 UT

Location of Jet Stream: Not over Scotland

Conditions: Still unsettled, blustery light drizzle and mostly cloudy with some clear spells. 10C.

Observations: Seeing (III), three systems resolved well, Delta Cygni B not seen cleanly at 260x under these conditions.


Date: September 14 2018

Time: 19:30-50UT

Location of Jet Stream: Currently over Scotland.

Conditions: Rather cool, (9C), very little breeze, rain cleared to give a calm, clear sky.

Observations: Seeing II. All four systems cleanly resolved at 260x and 354x


Date: September 16 2018

Time: 19:20-40UT

Location of Jet Stream: Currently over Scotland

Conditions: Mild (12C), fresh south-westerly breeze, some occasional clear spells.

Observations: Seeing very good (II), all four systems cleanly resolved at 260x and 354x.


Overall Results & Conclusions:

This study was conducted over the course of one month, from mid-August to mid-September 2018, a period covering 31 days.

The number of days where observations could be conducted was 21, or ~68% of the available nights.

No link was found between the presence of the Jet Stream and the inability to resolve four double star systems with angular separations ranging from ~2.5-1.5″. Indeed, many good nights of seeing were reported whilst the Jet Stream was over my observing location. In contrast, some of the worst conditions of seeing occurred on evenings when the Jet Stream was not situated over my observing site.

There is, however, a very strong correlation between the number of nights available for these observations and the efforts of the observer.

Many of the nights the Jet Stream was located over my observing site were windy, but this was not found to affect seeing. While the wind certainly makes observations more challenging, it is not an indicator of astronomical seeing per se. That said, no east or northeast airflows were experienced during the spell these observations were conducted. At my observing site, such airflows often bring poor seeing.

The archived data (from January 16 2014) on the Jet Sream site linked to above provide many more data points which affirm the above conclusions.

I have no reason to believe that my site is especially favoured to conduct such observations. What occurred here must be generally true at many other locations.

These results are wholly consistent with the available archives from keen observers observing from the UK in the historical past. This author knows of at least two (or possibly three) historically significant visual observers who enjoyed and documented a very high frequency of suitable observing evenings in the UK.

Contemporary observers are best advised to take Jet Stream data with a pinch of salt. It ought not deter a determined individual to carry out astronomical obervations. Perpetuating such myths does the hobby no good.

Post Scriptum:

June 18 2019: Irish imager, Kevin Breen, used his C11 to obtain decent images of Jupiter under a very active Jet Stream. Details here.

July 2 2019: Another testimony of “good seeing” under Jet Stream here


Neil English debunks many more observing myths using historical data in his new book, Chronicling the Golden Age of Astronomy.


De Fideli.