Dedicated to Rob Nurse
One of the most egregious myths promulgated by contemporary telescope forum culture is that one has to splash out large sums of money for a high quality telescope. This is especially the case with refractor—obsessed enthusiasts who have reduced the hobby to an activity more related to pornography than anything else. Serving more as ‘phallic symbols’ than tools, they spend countless hours ‘drooling’ like animals over instruments with tiny apertures, and revealing little or nothing of any substance or lasting value. Over the last two decades their designers have systematically robbed an entire generation of amateurs with their ridiculously priced ‘peashooters’ and all for the sake of better colour correction. Yet all the while, the reflecting telescope was systematically ignored or down played; that is, until this author blew the whistle.
As a former victim of this dead–end cult, I came to realise through experience that despite owning and using a suite of high-end refractors (think Takahashi, Televue, Meade, William Optics etc), inexpensive mass—produced Newtonian telescopes from the Far East were not only superior to the latter, but were easier and more comfortable to use. In a previous blog, I brought people’s attention to the SkyWatcher Heritage 130P flextube Dobsonian that revealed its superiority to much more expensive telescopes (in this case a high quality 90mm ED apochromat) on all targets. The key to providing these high quality views involved careful collimation and adequate cooling.
These thoughts came flooding back to me after this author acquired a used SkyWatcher 130P optical tube assembly for the princely sum of £65 plus £10 delivery. Once it arrived I was able to collimate the instrument and test it out for its high magnification performance on good daylight targets, where it was found to deliver excellent images with no image breakdown at powers up to and in excess of 270x diameters. Such a telescope had a well figured 130mm (5.1 inch) f/5 parabolic primary mirror with a secondary mirror obstruction of just 37mm (so a modest 28 per cent), which is significantly smaller than their catadioptric counterparts, and so should enable one to see finer, low contrast details on the Moon and planets.
Now, I wouldn’t expect you to take my word for all of this. That’s why the reader will also take note of reviews carried out on the same instrument dating back over a decade ago. In this evaluation, for example, the highly experienced reviewer reported no image breakdown when the telescope was pushed to magnifications of 250x. This also resonates with the findings of this in depth review made by another experienced observer a few years back. Failing these, the reader should also take note of comments from a varety of other users here and here. In addition, in this short thread, posted in the Cloudy Nights refractor forum, the tester of essentially the same optics (the Astronomy Without Borders, One Sky Newtonian) reported that it was quite close in performance to a 120mm ED refractor costing many times more.
In previous work, I noted that a properly—tuned Skywatcher Heritage 130P proved to be a better double star splitter than a 90mm apochromat. In the same report, this author noted how this modest telescope was also capbale of rendering a much more convincing split of tight systems such as Pi Aquilae than a previously owned and thoroughly tested Skylight 4″ f/15 classical refractor. This should not surprise anyone; when conditions are good and the optics are properly aligned, aperture wins.
That said, this new blog will not concern the optics in the 130P pictured above. Rather, what I wish to write about here concerns the consequences of transplanting my modified Heritage 130P optics into the closed tube of the 130P. How would they behave?
The reader will recall that the primary mirror of the Heritage 130P was left unchanged as I judged it as perfectly adequate. But what I did do was to get it recoated with the finest coatings money could buy (still a modest investment) and in this capacity sent the mirrors down to Orion Optics UK to have them treated with their proprietary HiLux caotings for increased reflectivity, reduced scattter and optimal durability. I also replaced the existing flat with one of slightly smaller size (35mm minor axis diameter giving a linear obstruction of just 27 per cent) and higher quality (read optically flatter, but economically so). But how easy was it to house those optics in the new tube? As it turned out; it was quite straight forward!
The primary mirror transplant was the easiest to perform, involving a simple swap of the existing mirror of the 130P (also centre spotted!) with the HiLux coated mirror from the Heritage.
The secondary mirror swap was a little more challenging. In short, they were designed differently, so necessitating the removal of the existing flat on the 130P secondary and gluing on the new flat derived from the Heritage 130P. In all, it took about half an hour of open heart surgery.
Finally, to ‘turbo charge’ the new closed—tube optics, I borrowed some Bob’s knobs from my 8 inch Newtonian and placed them on both the primary and secondary mounting cells as indicated below.
Justifying the Transplant
While the Heritage 130P flextube telescope is ideal for airline travel (check out SteveG’s report on how he brought it to Hawaii while on vacation) and for vacations within the UK, I wanted to be able to mount the same optics in a more stable tube, especially since it would be used regulalrly for high resolution work over winter at my home. After having extensively used the helical focuser on the Heritage tube, moving to a proper rack and pinion was a huge step up in luxury. Have you any idea of how much easier it is to hold precise collimation with this new focuser? I can assure you that such an upgrade is nothing short of pure, unadulterated joy!
Rummaging through my old box of tricks, I retrieved a colour matched 6 x 30mm finder which is a huge improvement over the RDF supplied with the Heritage 130P. RDFs are only adequate if you wish to locate the brightest stars. With the 6 x 30mm finder, I will be able to pinpoint much fainter targets to increase the efficiency of my observations. All in all, Plotina has a new and more stable winter coat.
Proof of Concept: Reports from the Field
Plotina belongs to a long and distinguished family of true and original apochromats. It’s fast f/5 relative aperture enables me to go from 20x and a very generous 2.5 degree field to powers in excess of over 300x for high resolution work, particularly in my chosen area of interest; double stars. In many previous blogs, I have also stated how good this little telescope was on the Moon and planets. Here I wish to continue her legacy by fielding my beautiful little closed—tube Newtonian under the starry heaven………
Date: November 4 2017
Time: 20:00 to 20:45 UT
Seeing: very good (II), frequent squally showers moving in from west, some good clear spells. Full Moon in the east.
Polaris: Excellent star test. Intra and extrafocal images almost identical at 200x. In focus image revealed the faint, wide companion even in the bright moonlight.
Epsilon 1 & 2 Lyrae: textbook perfect split at 183x using Baader zoom at the 8mm setting coupled to a 2.25x shorty Barlow. Beautiful and faithful colour rendition of the four components.
Delta Cygni: A decidedly more difficult target, but once again easily handled and beautifully rendered at 244x using a 6mm Baader orthoscopic and 2.25x Barlow. A gorgeous, brilliant white Airy disk with a faint steely grey companion well separated from the primary.
Almach (Gamma Andromedae): not really a test but a sight for sore eyes in this fine little telescope at 183x.Lovely contrast.
Iota Cassiopeiae: the highlight for me this evening, now not far from the zenith. I charged the instrument with a 2.4 mm Vixen HR ocular delivering 271x. Focusing was very easy to achieve and I was delighted to see it deliver a bright and perfectly formed image of all three components in their true colours.
A quick look at the full Moon at 20x using my trusty 32mm Plossl revealed a razor sharp image rich in contrast and in a relatively enormous field.
Comments: To say that I’m pleased with tonight’s results would be an understatement! I am beside myself! The Vixen Porta II is a good mount for this telescope with its smooth slow motion controls on both axes, and with the eyepiece at a very comfortable standing height for me (I’m a six footer). All tested oculars come to a precise focus easily with the rack and pinion.
23:05 UT to 23:35 UT ventured out again to test a few other tricky systems
Rigel: Easy at 81x despite its low altitude (still a wee while from culmination)
Eta Orionis; A corker at 243x! Very tight pair split with this marvellous 5.1″ speculum at a suboptimal altitude.
Theta Aurigae: Now favourably placed high in the eastern sky. Easy split at 183x
Date: November 5 2017
Missed an early session this evening, as we ventured out for bonfire night. Anger nonetheless kindled against those supposedly ‘experienced’ peers who left this amazing, economical telescope in the dust. Why did you not test it? Too busy drooling were you? Why did you not advise your peers about it? How many amateurs might benefit from using this instrument?
You really need to examine yourself!
Shame on you!
Time: 21:45 UT to 22:30UT
Seeing: II, remaining very good, very cold and clear, bright Moon in the east.
Iota Cassiopeiae: Easily resolved at 183x but better seen at 243x
Theta Aurigae: Observed once again this evening. Companion beautifully resolved from primary at 183x
Pushed the telescope hard on the waning gibbous Moon this evening. The telescope delivered wonderful images at powers from 20x to 325x! No image breakdown recorded at any of these powers. Wonderful images delivered in these sub–zero temperatures.
Comments: Lambda Cygni (0.9″) is now past its best and slowly sinking into the western sky, but I will attempt 52 Orionis (1.02″) and 36 Andromedae (1.14″) over this coming winter. I cannot for the life of me see why Plotina cannot resolve these systems under good conditons. Can you?
Date: November 6 2017
Having a proper finder is a wonderful upgrade to the RDF supllied with the telescope. As stated previously, RDFs are only useful with the brightest stars and often, in colder conditions especially, the battery ceases to deliver its power rendering such a device useless. What is more, as a guy who likes to do all his observing without electronic appendages, fitting a traditional finder to this small Newtonian made a great deal of sense. When properly aligned it’s possible to centre objects, even at high magnification, increasing the efficiency of my observing sessions with this telescope.
Of course, one of the great joys of using this f/5 Newtonan system is the substantial increase in light gathering power it delivers over other other telescopic designs. Actually, it’s an enormous increase over a typical, small grab ‘n’ go refractor or Mak and will make your ‘quick look’ or grab ‘n’ go excursions far more rewarding than using an 80 to 100mm refractor, say. F/5 is not so fast that one requires a coma corrector or some such and the field of view with a modest 32mm Plossl is quite well corrected across the majority of the expansive, 2.5 degree true field. One thing is certain; this telescope will be an absolute ball to use in the exploration of the winter deep sky.
Having a new winter coat avoids the need to fit a makeshift light shroud to the upper tube assembly, such as is the case with the Heritage 130P/ One Sky Newtonian. This affords a greater degree of protection against dew and stray light combined. The increase in mass is negligible too; you can pick up the ‘scope with one hand or carry it under your shoulders even over a considerable distance.
As I noted with the Heritage 130P, quick acclimation is eminently possible with this telescope and my observations thus far made with the closed tube 130P give me little cause to think that its cooling off time will be substantially increased. 15 minutes is probably all you need, so even the laziest of you readers can get to work on the sky quickly and easily.
As described previously, I use a simple, inexpensive laser collimator to get quick and accurate alignment of the optical train. I consider the laser collimator a great improvement over the traditional ‘collimating eyepiece.’ My high magnification tests conducted thus far show that the more stable housing of the optics in the 130P maintains this collimation significantly better, so there is far less anxiety involved in moving the telescope about.
One of the greatest (and largely unsung) assets Newtonians have pertains to their ability to be collimated rapidly. I’ve lost count of the number of stories I’ve read of folk who accidently whack their refractor or Mak tubes off a wall or door or some such and then worry that the optics may have gone out of alignment. For a Mak, the issue can be resolved at home, but not very easily. For a refractor, you’ll likely have to send it off to some specialist for proper realignment of the lens elements; and at an additional cost to you. All of this, of course, is superfluous to the man who learns to collimate his Newtonian. You can bump it off any wall you like and still have the reassurance that it will be working optimally in a matter of minutes.
In this capacity, Newtonians are the ultimate, low stress telescope.
The weather has nose dived in the last twelve hours back to mild, wet and cloudy. Time to take a break from this blog and return again when conditions permit more testing.
Toodleoo the noo.
Date: November 7 2017
Time: 22:11 UT
Seeing: I to II, excellent, good transparency, waning gibbous Moon, not too overwhelming (yet).
While some of you were drooling on the fora, I was busy finding 36 Andromedae while the Moon was still low and monitored it at low power until it crossed the meridian at 22:11 UT or thereabouts. Charging the 130mm f/5 Newtonian with a 2.4mm HR ocular delivering 271x I can report a fine split of this system. Both stars separated by a sliver of dark sky and distinctly yellow in colour. The view was even more compelling at 325x. Perfect Airy disks! This is a magnitude 6/6.5 pair and the separation is 1.1″.
This telescope rocks!
Let goodwill and common sense prevail!
As always, I would encourage others to see if they can split this system with a 5 inch Newtonian reflector. Make sure your optics are well collimated and the instrument fully acclimated (you don’t need a fan either). You’ll be very surprised what you will see under good conditions!
As you can gather, I have dedicated this blog to Rob Nurse, who has started a friendly correspondence with me. I learned that back in the early to mid 1990s, Rob employed a little Tal 110mm f/7.3 to divine some pretty tight doubles using this reflector and has been following my work. Below is just one page of some of his results (used with permission). This is more evidence that well made Newtonians are excellent double star telescopes.
I hope you can see that he managed to split pairs down to about 1.3″ and his success was better the higher in the sky these pairs were situated. I suspect that he was wasn’t trying particularly hard to push the instrument though!
We need to keep working hard to root out the evils in this hobby, so feel free to help out if you can.
Date: November 8 2017
Last night was very exciting but I had to cut it short. 36 Andromedae was not a particularly difficult system for this telescope. For the record, it’s very close to the Dawes limit for a 4 inch unobstructed aperture. But in the right hands, the 130P is capable of doing significantly better than the finest 4 inch refractor money can buy. If you think otherwise, you’re simply deluded. Like I said before, I once drooled over a very fine 4″ inch f/15 refractor that set me back a small fortune. Yet this little reflector in my possession can outperform it; and I only needed to do some simple tests to affirm this. And no amount of justifying can change that fact.
For me, the reflecting telescope has been an instrument of liberation. Isaac Newton( 1642—1727), arguably the greatest scientific genius ever to have entered the human arena, invented this marvellous telescope. I think this was meant to be. But I hope you too can learn something from the hard lessons I have learned. The beauty of the Lord’s created Universe is not to be enjoyed only by an exclusive few. It ought be enjoyed by everyone. And the Lord has made this technology available to all at relatively little cost through the reflecting telescope. Pride has died; gratitude is born (sic gratia non superbia).
52 Orionis is that little bit beyond the capabilities of a 4 inch aperture but should be quite doable with the 130P. I will have to wait for another good night to ascertain this.
Rob was also kind enough to provide a short list of other systems that will be interesting for those with small reflectors to visit over the course of the seasons. Some of these entries are dated but it would be fun to visit them nonetheless to see how they’ve changed over the years.
I’m blessed by having more quality eyepieces than you can shake a stick at but you don’t need to have the finest collection of ultrashort focal length oculars to boost the power in a short focus reflector. By far the most economical way forward is to invest in some Barlow lenses that can boost the power of the eyepieces that you may have in your possession. For example, the Baader 6mm classic orthoscopic yields 325x with a 3x shorty Barlow and 243x with an economical 2.25x Barlow. My excellent Parks Gold 7.5mm ocular is also a great choice when coupled to a 3x Barlow yielding 260x. You can also get good results by Barlowing a medium focal length Plossl (a 9mm is a good choice).
Date: November 9 2017
Faster, Cheaper, Better
If you’re thinking ‘phallically,’ then you’ll likely say the 90mm refractor is better; afterall, it has a smoothly gliding extendable dewshield and a super ‘sexy’ dual speed 11:1 focuser. It resembles a phallus too and ‘looks the part’ alongside you in a comfy, twoseater sports car. But if you’re thinking Biblically, using your eyes and brain as God intended you to use them, then it’s easy to see that the 130mm gives a much brighter, cripser and more detailed image at the same magnification and all with perfect colour correction (the refractor only approximates true colour correction). In previous work, I showed that the 130 Heritage truss tube configuration could split tighter double stars, resolve finer planetary details and pulled in fainter deep sky objects than the aperture—challenged refractor. Using inductive reasoning (but also adding my own ongoing experiences to the mix), the closed tubed 130P ought to do likewise….. and it does.
Here’s the rub though. The optically inferior refractor is valued much higher than the reflector; many times more in fact. Why? God only knows! But I’ll give you my opinion; because it is seen through the corrupt lens of the phallus. You’re literally thinking like a Dick. That’s the ridiculous situation that has precipitated because of our blinkered perception of value and which has gone largely unchecked for nearly three decades. What’s the refractor really worth? To a visual observer, slightly less than the reflector, surely?
Don’t be a phallus.
Date: November 10 2017
In case you’re wondering, the 130P is actually slightly lighter than the 90mm Apo and should probably cool off just as quick as the latter. It’s also small enough to fit in a comfy twoseater, so there’s absolutely no excuse not to consider it as a most powerful grab ‘n’ go telescope.
This very morning I set up Plotina in my back garden to exploit the feeble autumn sunshine, looking at the now denuded branches of deciduous trees located a couple of hundred yards distant. Incredibly, I was able to crank up the power to 406 diameters using a Vixen 1.6mm HR eyepiece and the images garnered were beautifully sharp and rich in detail. That’s over 80x per inch of aperture folks; no’ bad…..ken.
Yesterday evening the veteran Romanian observer, Mircea Pteancu, kindly reminded me that he has managed good splits of 52 Ori , 36 And, Antares and Nu Sco, using a homemade 127mm f/7 Newtonian reflector, adding another experienced voice to the list. You can read more about his findings here. F/7 must be a wonderful place to be in a 5 inch reflector. I bet it would hardly ever need adjusting and focusing would be child’s play. I’m envious of f/7 but f/5 will do admirably.
Low Power Sweeping
After I had finished with the students and grabbed a bite to eat, I noticed that there was a few clear spells and no Moon between 8pm and 9pm local time, so off out I went with the 130P and decided to stick with just one eyepiece; my good old SkyWatcher 32mm Plossl. The markings on the barrel are long gone by now but there’s still no mistaking it! Truth be told, it is one of my fondest and most used oculars. Delivering a power of just 20x in a splendid 2.5 degree field, I enjoyed beautiful views of the Pleiades, now climbing higher into the eastern sky. From my dark country home, the hinterland to this much loved open cluster is coal black in the telescope, its individual stars, tiny incandecsent jewels shining through the darkness. The 32mm Plossl gives a very well corrected field, with stars even at the edge presenting as very acceptable. It’s comfortable eye relief makes it a good choice for those who wear eyeglasses.
From there I ventured high overhead to the Perseus Double Cluster and boy was that a sight for sore eyes! It’s singular beauty never fails to set my heart racing and it was splendidly framed in the wide, well corrected field. From there I inched the telescope further eastward, centring the wonderful Alpha Persei Association in the 32mm oculus. Thereafter, I swung the ‘scope back westward into Cassiopeia and enjoyed staring at the fascinating ET cluster for a wee while. It actually looks best in the Newtonian, as the upside down image presents it the ‘right way up’, as it were. Sweeping the instrument through this constellation is always a special treat, with myriad Milky Way stars dazzling the eye.
Spotting a hole in the clouds in eastern Pegasus and Andromeda I homed in on the great spiral galaxy M31 now very high up, its bright, lenticular core showing up very well together with its gradually fading spiral arms. The two satellite galaxies were also apparent with averted vision. Moving west into Cygnus, I enjoyed the radiant colours of 30 and 31 Cygni, which are much more compelling in this telescope than they appear in large (70mm) binoculars. Comely Albireo was also resolved at this low power.
Finally, I swung the telescope over to Auriga, and after a minute admiring the silent beauty of brilliant yellow—white Capella and its starry hinterland, I swept through the belly of the constellation, seeking out the compact open clusters; M36, M37 and M38. Though I could have done with more magnifying power, I was pleasantly surprised how well they looked at 20x.
I’m deeply impressed with the performance of this economical telescope, being capable of every kind of astronomical application you might need it for. In fact, it has no significant weaknesses. It’s very lightweight, so even those who are frail can get fair use out of it. Indeed, though I am personally enjoying the prime of my life, I can easily lift the telescope on its mount a considerable distance with only one hand. It’s easy to store too and won’t take up much room. I keep mine under my bed lol! It’s an unbeatable bargain for those on low incomes as well as pensioners, and will delight its owners with years of productive use.
Date: November 13 2017
The 130 is so lightweight that it can be used profitably on a number of economical mounts. I generally use the Vixen Porta II with this instrument. The wonderful thing about the Porta II is that the tension on both axes can be adjusted to perfectly match the mass distribution of the telescope. The supplied hex wrenches that sit under the mount head can be accessed at a moment’s notice to make those small but important adjustments to the tension that make the telescope move very smoothly, even at high power.
Because the telescope has a standard set of tube rings, one can also adjust the position of the instrument’s base so that observing at the zenith is easy to achieve.
The Porta II can also be adjusted in height to permit very comfortable, standing or seated observations. Thus far, I’ve only observed through the telescope in the standing position, as the weather has been so unsettled that a shower can turn up necessitating the instrument’s rapid transport indoors. But I hope to enjoy this telescope with a comfortable seat during more settled spells.
The same telescope can also be neatly mounted on the simple table top mount supplied with the Heritage 130P. When mounted on a small table, it can be used with ease for low and medium power sweeps but I would recommend a more sturdy mount for the highest power applications.
And for those who enjoy equatorial mounts, the instrument is well matched to the fairly lightweight EQ 2 mount. Indeed, one can purchase the 130P along with the EQ 2 mount as a package from SkyWatcher or Orion Telescopes & Binoculars(USA). These mounts can easily be upgraded for smooth motorised tracking too. See here for a quick over view of its operation on such a mount.
There is also a number of lightweight, fully computerised GoTo mounts that can be mated to the 130P if that is your thing.
These are just some of the mounting configurations you can use with this telescope. None will break the bank and all should provide years of hassle free use. My preferred mounting for this fine instrument is the Vixen II as I’m not entirely bowled over by equatorials. It has given this author several years of flawless use with a number of telescopes, and has travelled with him the length and breadth of the country.
During the middle months of the year, where sunlight is abundant and the length of the day is long, smaller aperture spotting scopes make near ideal tools for studying nature, but as winter approaches (and at dusk and dawn) at high northern latitudes, having decent ambient light becomes much more of an issue. This is where the significantly increased light gathering power of the 130P really shines. On a dull, overcast, winter day, only a couple of hours of decent lighting is available for nature studies. But it is in these conditions that the 130P shows itself much superior to conventional spotting ‘scopes. Where powers of 100x or above are really stretching the 80 or 90mm ‘scope, powers twice that and more are achievable with this ultraportable 5.1” Newtonian.
Of course, the Newtonian reflector provides an upside—down view of terrestrial scenes and while there are ways of getting decent right—side—up views, in practice it matters very little. When coupled to a digi—scoping device, the images can be easily inverted later on your pc. When you’re examining the fine structure of tree trunks and branches or the splendid high magnification detail of leaves, rocks and wildlife in ultra—high resolution, you’ll soon forget about those upside—down images and delight instead on the rich details afforded by this optically excellent light bucket.
Because it gathers a very generous amount of light, you can also employ filters such as a polariser to cut through glare in the landscape and increase contrast on the brightest days.
Indeed, using both the Heritage 130 and the closed tube 130P extensively during the day has caused this author to question the dominance of other kinds of telescopes in daylight applications. It might not look quite as sexy as a Questar 3.5 or 80mm shorttube refractor but one look through the Newtonian will quickly reveal its clear superiority to the latter. And of course, there will always be some who balk at the Newtonian and reject it only because of its inexpense; sad I know, but that’s their problem and not yours, right? lol!
Don’t be a slavish follower of fashion; take your daylight observing elsewhere.
Date: November 14 2017
The last several nights were either cloudy or too unsteady to continue some of the high resolution work mentioned previously. Many of the clearest nights have been cold but very turbulent owing to strong northerly air flows, which always deteriorate high magnification views in these parts. Things were so bad in the wee small hours of Monday morning last that the telescope was unable to steadily hold the four brightest members of the Orion Trapezium! But I am thrilled to bits with the deep sky performance of the 130P. The Great Nebula still looked magnificent in the opulent field presented by the 8mm setting of the Baader zoom eyepiece (81x) and far more compelling than either of my shorttube refractors (80 and 90mm) can ever deliver. It’s a powerhouse of honest to goodness performance!
I will report some more once conditions improve.
Date: November 16 2017
I enjoyed another bright and sunny late morning/early afternoon session with the 130P. I re—tested its ultra—high power performance on daylight targets. I can again confirm that the instrument is good to go at 406 diameters i.e. the image remains fine and bright and beautifully crisp across the entire field of a Vixen 1.6mm HR ocular. For the most part though, I am sated under these conditions by the 183x vista rendered by my Baader zoom and dedicated shorty Barlow, which delivers an amazing 0.4 degree true field.
Iblis scurries to and fro, scheming, desperately seeking to inflict harm on her. Yet no matter how much mud the enemy flings at Plotina, nothing sticks.
Like a faithful Collie, she just goes on strutting her stuff, by day and by night; naturally, gracefully, effortlessly; delighting her master.
Tonight looks good for yet another session under the stars.
Time: 22:30 UT
Seeing: 2.5 Ant, excellent sky transparency, brisk westerly winds driving in some intermittent wintry showers.
Tonight, I set up Plotina to assess the seeing and targeted Theta Aurigae now situated favourably well above the horizon in the east. The telescope delivered a wonderful split of its B and C components at 271x. The former is tucked up real close to the substantially brighter primary (magnitudes 2.6 & 7.2, respectively) with a separation of about 4″.
One of the keys to getting success out of a Newtonian telescope on such high resolution targets is to be patient. The telescope generates some thermals especially on colder nights, where the high magnification image breaks up momentarily before coming back together again. One moment it morphs into a swollen mess of light but as it moves across the field the image settles down and delivers beautiful, textbook perfect images. You need to spend time with the telescope to learn how it behaves before you can get the most out of it, or to speak, with gravity, concerning it.
But I had bigger fish to fry. High overhead at this latitude on mid—November evenings lies mighty Cassiopeia, and under these fine conditions I homed in on Psi Cassiopeiae, a system I have given mention to in regard to a very fine Orion 18cm f/15 Maksutov cassegrain I put through its paces a few years back. The primary shines with a beautiful soft orange hue but about 20″ off to the east of it lies the faint C and D components (magnitudes 9.2 and 10.0 respectively) and are separated by a mere 2.3.” The challenge is to be able to see them clearly. Needless to say, the large Maksutov made light work of these faint companions but my field notes show that I could also see them with my very fine 5 inch f/12 classical achromat but only with a concentrated effort. The test tonight was to establish whether or not I could do the same with this 5.1″ f/5 reflector and I can report that the answer is affirmative! I employed a magnification of 183x and a concentrated gaze. This is not an easy target, but it is just possible with this telescope under near ideal conditions.
What does this observation establish you may ask?
It shows that the light gathering power and resolution of the 130P is on par with the 127mm f/12 refractor.
No’ bad, ken.
I ran in to inform my wife of my progress but loitered too long beside the fire, unfortunately. When I went back outside, it was raining and the poor telescope (and some choice oculars to boot) got a substantial drenching!
But the 130P is no’ a Big Jessie ‘scope and a dousing of water from heaven does little to dampen its enthusiasm.
Date: November 17 2017
If it wasnae fur yer wellies, where would ye be? lol
You’ll be glad to know that Plotina made a full recovery and is now ready for more action under a starry sky.
Weather still looks iffy though but since the telescope cools off as fast (maybe faster; greater surface area an’ that?) than a small refractor, it can still be used as the ultimate shower dodger.
Date: November 18 2017
More on Faster, Cheaper, Better
It was another crisp, cool and bright day here in Scotland. And with some free time to cogitate upon the 130P, I can confidently report that its performance lies midway between a high quality 4 and 5 inch refractor, but at a much reduced price to the consumer. As I’ve demonstrated, it ticks all the boxes that an ‘apophile’ might make in an argument concerning image fidelity, portability, rapidity of cooling etc. How it looks should be of little concern to a dedicated observer, but maybe some value ‘form’ over ‘function;’ why, I’ll never understand!
Telescopes are not idols.
It must be stressed that my major objection to apochromatic refractors is their exorbitant cost per millimetre of aperture; a price I am personally unwilling to pay as I can make much better use of my disposable income (I’m frugal and I consider that a virtue). Simply put, their prices are far higher than virtually any other type of optics on the market and that alone will make them a prime target for new and more cost—effective technologies now being developed. Unless the prices of these instruments are significantly reduced, they will be superceded by new technologies that are faster, cheaper and better. For example, a few years back, this author introduced the amateur community to a novel flat lens technology that will surely revolutionise telescope optics if the good Lord grants us enough time to see it to fruition. The technology (now being developed for visual wavelengths as the article indicates) is scalable and affordable. Let us hope that they succeed in their researches!
In the meantime though, it pays to take a hard headed look at other affordable telescopes already on the market, and in the same aperture class as the 130P, to see how they measure up. As I said before, the 130P is in a completely different league to 80mm ED ‘scopes and 90mm Maks (including the venerable Questar 3.5). Consider if you will, the Celestron C5, reviewed here in good detail. The instrument is quite portable but will take considerably longer to acclimate if taken from a warm room to the cold night air. With a focal length of 1250mm (so f/10), it offers up a maximum true field of about 1.25 degrees; that’s only half the field possible in the 130mm Newtonian! And with a central obstruction of 37.8 per cent, its performance on lunar and planetary targets will be noticeably inferior to this reflector (recall it’s only 28 per cent and mine was reduced to 27 per cent). Price wise, you can purchase a 130P and decent mount for much less than the C5 optical tube assembly alone!
Better still is the 127mm f/12 Maksutov. This has an even longer focal length (1500mm), reducing the maximum true field to about 1 angular degree. But it still has a central obstruction of 33 per cent and takes quite a while to acclimate (that is, if you’re unprepared!). 33 per cent is, of course, better, but not nearly as small as the obstruction in the 130P. This means that if the latter optics are decent, well collimated and suitably acclimated, it should outperform the former on low contrast targets under good seeing conditions. In this realistic review, the author correctly concludes that the 127 Mak rivals that of a top class 4 inch refractor in average conditions. So a good 130P (also cheaper than the 127mm Mak) such as the unit in my possession, should do that little bit better don’t you think?
Date: November 23 2017
A Virtuous Telescope
After several days of rain and cloudy skies, the weather has turned much colder once again, bringing bright blue skies by day. Much of the north of the country got its first fall of snow in the wee small hours and we even got a sprinkling here but it didn’t settle. Making the most of the bright light, I once again tested the ultra high power performance of the 130P on a number of targets between 50 and 200 yards distant. Charging the telecope with a power of 406x, I got precisely the same results as I obtained before; namely, the telescope yields very sharp and detailed images (n=3) at this power, testifying to the quality of the optical system. This power ought to be useable on the best nights to ferret out the tightest doubles accessible to the instrument.
Today, of course, is American Thanksgiving Day, and I would like to wish all my US–based readers happy holidays!
Conditions look clear for tonight, so I may be able to report back later this evening. Tomorrow we travel 127 miles north for a short vacation. Needless to say, Plotina will be travelling with us in the hope that I can enjoy a short adventure with her under a very dark, winter sky.
I could do with a carry case for the telescope. But it’s certainly not an essential feature. Afterall, the instrument can be carried in your lap, or safely stored with the rest of the luggage in the boot of the car. And even if it gets knocked about, it’s easily remedied by a quick and accurate collimation once we arrive. No sweat!
I’ve just noticed that the eyepiece holder can accomodate a T2 adaptor to mate a camera or webcam to the telescope. That’s a nice touch, but something that doesn’t interest me, as I’m purely a visual observer, but it does means that the instrument can be used to do some entry–level imaging when coupled to a motorised tracking mount.
Gosh; are the virtues of this telescope ever going to come to an end? I wonder!
To be continued……..