Unitron/Polarex Model 114 60mm Review
How a telescope should look: the elegant Unitron refractor.
Unitron telescopes have a classic elegance matched perhaps only by Questar. Many amateurs of my age will recall the Unitron adverts that appeared in magazines like Sky and Telescope in the 60s and 70s, perhaps when they were children just getting interested in astronomy.
In Europe, Unitrons were badged as Polarex, but the telescopes are the same long glossy white tubes with black fittings and mounts. Unfortunately, back then telescopes were relatively even more expensive in Britain than they are now. My family couldnít afford a Unitron (didnít even know how to obtain one: the ĎStates seemed very exotic back in the Ď70s and the adís in my Seventies Sky and telescopes might have come from another planet) and even the Tasco three inch I bullied my Mum into buying me cost a whopping £300 in 1977 and had to be imported. I remember waiting all Summer for it and making my Mum phone the local camera shop every five minutes to see if it had arrived.
Now, it seems a fact of life that if you really want something as a child, you go to great lengths to get it as an adult ... So, of course, having wanted a Unitron then and having had a thoroughly disappointing Tasco instead, I still wanted one now.
Design and Build
The Unitron is a 60mm F15 (900mm) achromat. Itís a completely traditional configuration that can deliver excellent images with very little chromatic aberration. The lens is a classy-looking affair with a finely engraved lens ring and good coatings for the times. It looks vastly superior to the run of 60mm refractors. In practice, Unitron lenses were made in various small Japanese optical shops and quality isnít what you might expect from its appearance.
Unitron/Polarex 60mm F15 objective.
The tube is long and enamelled in a brilliant white. At one end is a push-fit white dew-shield, at the other various handsome fittings accented in lustrous black. Did I mention it looks good? The tube comes with a pair of brackets to hold the rod for a solar projection screen and all such accessories on the Unitron are made from hard, brittle Bakelite. Mostly the Unitron is a high quality device, but those Bakelite fittings for the finder and sun screen holder tend to crack, old as they are.
The focuser is unusual - a long, push-fit drawtube and short-travel rack-and-pinion with the black Bakelite knob (matching the ones on the mount) on the right side only. The draw-tube provides coarse focusing, the r&p fine. It would be a good system but there is some flex in the drawtube and it can Ďsagí when extended. I found greasing it sparingly tightened things up.
Quirky focuser combines draw-tube with single-knob rack and pinion.
The tube fixes to the mount head via a little black clamshell secured by a couple of Bakelite knobs - no dovetails back then. The mount itself is the same black enamel as the clamshell and the tube fittings, whilst the mechanical bits appear to be stainless. The mount is small and very well engineered and sits on a set of long tripod legs made of what looks like boxwood. †Slow motion controls Ė smooth and accurate Ė are provided for both axes.
Unitron alt-azimuth mount.
The Unitron 114 comes packed in a wooden crate with its accessories, like most quality refractors of the time. That wooden crate contains a high quality 4x finder in an unusual stainless tube; four 0.965 eyepieces: a Ramsden 25mm, Kellner 18mm and 12.5mm and a Sym (read Orthoscopic) 9mm; a dangerous looking clip-on Sun filter; a decent 0.965Ē prism diagonal and a strange barlow that pushes into the front of the diagonal.
Sitting in its box, the OTA looks graceful ... and long! I can imagine some child from a well-off family in the Sixties, with the Space Race delivering exciting new discoveries every week, excitedly opening that box for Christmas or birthday.
Included eyepieces: A Ramsden, two Kellners and an Orthoscopic (ĎSymí).
The first thing to say about the Unitron in use is that here is a grab-n-go scope from before anybody ever used that term! The whole outfit is very light, even on its long wooden tripod and itís a trivial lift for anyone but the infirm. Big it maybe, but the Unitron could be used by an older child.
The Unitron mount is excellent. With practice you can set the tensioners so that you can push it around, then use the slow motion controls for fine adjustment. The slow motion controls are both on the front of the mount and donít change position much as you slew around, which is very convenient. They work by moving a lever against a spring-loaded plunger, so travel is a bit limited; the same mechanism works the Declination axis on my Takahashi P2Z mount.
The only down-side of the mount is vibration from the long tube, which takes a while to settle at high powers. Overall, though, the Unitron mount is much more convenient than a modern TelePod in many ways. At high power, the TelePod needs lots of nudging, whilst you just twist the Unitron knobs to keep the object in view, with much less risk of losing it.
The field of view from the 0.965Ē Kellners is very narrow, so you donít get the full Moon in the field above about 50x. This makes finding things unusually painful for a small scope, so itís a good thing that the finder is excellent with a wide field, clear reticle and decent eye relief.
Close inspection of the Unitronís optics with a star test reveal less than perfect optics; I wonít say more as it seems churlish to criticise this classic, like wheel-spinning an old Jagí. I have read that these optics were rarely even diffraction limited, so this one is doubtless typical. I used to think that was just how things were in the 1960ís before modern optical testing and fabrication Ö then I acquired a 1964 Swift 838. The Swift has a superb star test and is super-sharp in-focus, making me wonder why Unitron were unable to achieve the same level of quality.
At F15, with a 60mm objective and basic coatings, itís not surprising the Unitron is at its best on the Moon. With the 25mm Ramsden giving 36x the Unitron delivers crisp, sharp views, with very little chromatic aberration. The Moon remains detailed and sharp, with lots of craters along the terminator, in the 18mm Kellner at 50x and even up to 72x in the 12.5mm Kellner. But the 9mm Orthoscopic (ĎSymí) at 100x is just a bit soft and you know it wonít take much more. The Unitron just wonít take my 7mm Takahashi MC orthoscopic (in contrast to the Swift 838, which gobbles it up and asks for a five). The good contrast and well controlled CA demonstrate the potential of a small, long focus achromat, but you sense that optical quality isnít the best, star-test confirmation not required.
Comparisons with the 60mm grab-n-go scope that I use, Tele Vueís TV-60, are interesting. The Tele Vue 60 is a tiny 60mm doublet APO with superb optics and a very modern design which I generally use on Tele Vueís own push-pull TelePod altazimuth mount. Both the TV-60 and the mount are the subject of separate reviews, so I wonít go over old ground here, except to recall that the TV-60 is a tiny, black, CNC-made conical object† with a helical focuser which looks nothing like a telescope, but which works extremely well.
Unfortunately, nice though it is on the Moon at medium powers, at higher powers the Unitron reveals its age. Using the same 12.5mm kellner in both the Unitron and the TV-60 (with a 2.5x Powermate to equalise the power), the little Tele Vue is sharper, brighter, much more contrasty. For example, the Huygens Rille is obvious in the TV-60, much less so in the Unitron. Whatís more, the older scope just doesnít convey those luminous icy whites, hard blacks and soft greys, all those subtle maria shadings the TV-60 excels at. In the end I just put the Unitron back inside, popped a 5mm Nagler in the Tele Vue and enjoyed the view.
The only planet I tried was Jupiter. The view was adequate, revealing the basic equatorial belts and Galilean moons, but the view through the TV-60 was in another league (as is that delivered by the 50mm Swift 838).
It looks good Ö really good.
The Unitron looks frankly beautiful and is very well made. Iím admiring it from across my living room as I write. It may perform much like a cheap 60mm Ebay telescope from today, but of course looks and build quality are in a whole different league. Even thatís an unfair judgement, because the Unitron is from an era before ray-tracing programs and laser interferometers and CNC optical grinding machines and multi coatings.
Think of the Unitron like a classic car. It works nicely for the era and age; just donít scrutinise the star test too closely, or try comparing it with a TV-60. Looked at, the little Tele Vue is a dumpy object of indeterminate purpose, compared to the elegance of the Unitron; I know which Iíd rather have in my living room! But compare the view through the two and the Tele Vue is superior in every way and proves that nostalgia ainít what it used to be.
But did I mention that the Unitron looks good?
Recommended as a magnificent-looking classic. But if you want an antique with performance to match its looks, buy a Swift instead.