Unicon 50×600

Unicon 50×600 f12

This is a scope i bought some time ago, early last year as i recall and since then i’ve been modifying it and seeing what it’s capable of. I do remember shortly after the purchase someone on either Cloudy Nights or StarGazers Lounge, passed a comment about maybe the purchaser was under the mistaken impression that this was a Unitron!. Seriously? I doubt anyone that knows about Unitrons would think they’d get one for the tiny sum i paid for this scope (£27 inc shipping!). At the time i was interested in small scopes from the 50’s to the 80’s, knowing that most scopes of that era were optically good and somewhat better quality than today’s offerings. Japanese construction with wooden tripods and cast mounts, all much superior than the spindly plastic and aluminium gear supplied with most modern items. Above all, it was cheap…. and i can’t resist cheap.

With any unknown scope comes the gamble that what you’re buying is rubbish.. after all one of the reasons people sell things is because the item in question is crap. Luckily i got a very good scope for my money but with a little work on my part. The focuser and objective cell are plastic, the tube is aluminium but cost cutting is evident. The inside of the focusing tube is brass coloured and shiny as hell. The cell is held in place by one screw that isn’t properly countersunk and pushes on the dew shield. The focuser itself isn’t properly aligned and needed modifying. All in all, some might say the scope was a bad product, but like nearly all the scopes i own, a little work here and there makes an okay scope into a real performer. When you consider that the scope came with eyepieces, diagonal and a wooden tripod the cash and time i spent was worthwhile. It’s light, portable and it performs as well as any 50mm scope should.

Observing produced good results, Sigma Orionis was split beautifully, Also Castor in Gemini and finally Algieba (gamma leonis) was beautifully split with the secondary sitting nicely on the diffraction ring of the primary. A trip around Orion was cut short by cloud but at least the cloud had parted long enough to get a few doubles in. Overall this scope performs really well, it was a gamble buying it as i knew nothing of the brand or the lens manufacturer. I’ll post a little more about manufacturers in a later topic, for now though i would recommend the Unicon to anyone looking for a good low price 50mm scope. That said, this is the only example i’ve seen, but there is a Jason model with similar build and lens manufacture.

Towa 30-90x 60mm Variable

As the title says, this is Towa’s own version of a variable mag scope which has been sold under such brands as Tasco, Prinz etc. It’s really supposed to be an economy version of the regular diagonal and eyepiece scopes. Economy is certainly not a name i’d give this Towa example, the optics are really good and the variable mag makes it so easy to use.

 

I do own a few variable mag scopes from 5 different manufacturers, and i have to admit they’re a bit of a mixed bag. This Towa is a cut above the rest, not sure if it’s because they supply a lot of companies with objective lenses and just chose the best quality for their own? maybe… but the end product is certainly worth keeping. The starting mag of 30x may seem a bit overkill especially if you’re observing something new and aren’t on familiar ground (or sky), which is something that needs addressing. I will modify mine at some point with a red-dot finder or similar. This minor niggle aside the scope and tripod are good quality. Metal objective cell and metal focuser are standard from this period, the only plastic parts are the mounting knobs and focuser knobs. the eye relief is comfortable although i don’t wear glasses but think spectacle wearers will find things a bit snug. The wooden tripod is very stable, with this reasonably light scope the vibrations settle down really quickly which helps a lot when you’re adjusting magnification and focus all the time. When adjusting the magnification using the rotary adjustment the scope only needs refocusing every 40x or so, sounds strange but… if you’re scanning the sky at 30x then decide to zoom on an object, you don’t really need to refocus til around 60-70x. Then when focused you only need to refocus at around 85x or so.. I was fully expecting to have to refocus around every 10x increase in mag but the reality is exactly opposite.

Rotary Mag adjustment means no tripod jolting when changing mag.

 

I say you don’t have to refocus but the image does get less sharp. meaning you will have to refocus once you’re happy with the chosen mag. This is totally unlike using a diagonal and ep’s where changing a 20mm eyepiece to a 10 means having to refocus as the target becomes a blob or goes out of your field of view. With the variable mags like this one you unconsciously keep the target in your f.o.v as you increase mag. Other variable scopes have the clunky push pull mag change that means a refocus at every mag increase. This is probably part of this scopes charm.. ease of use. The Mag adjustment and focuser being so close together means adjusting both at the same time causes less wobble and reduced vibrations.

 

I do own a Prinz Astral 100 which is almost the same but with kenko optics, the mag adjustment is push pull and a bit clunky. Sometimes it takes so much effort to change mag that you knock the scope off target and find yourself at a higher mag searching for your target with a tiny out of focus f.o.v…. not recommended. Adjustment issues aside the Prinz 100 is a perfectly good scope with good optics. Quite often the optical train used in these variable correct image scopes is of poor quality, not so with the Towa or the Prinz. 60mm aperture is probably the best starting point for variable mag as smaller scopes suffer from dim images due to poor quality lenses used in the optical train.

 

The Towa with good seeing will split the Trapezium in Orion to 4 stars. Other tatgets which are good for testing these scopes are Castor in Gemini and Sigma Orionis which splits nicely. As an all round telescope the Towa works really well, it’s portable light weight makes it a good grab n go scope and you don’t need a handful of eyepieces. I would like to see a few more of these variable mag scopes aimed at astronomy, it seems nowadays you can only buy spotting scopes which just like these vintage items are a bit mixed in quality. The modern solution to variable mag is to mount a 45 degree correct image diagonal at the end of a short focal length scope, then fit a zoom lens from the likes of Celestron. These scopes give a typical 15-45x mag which is pretty useful for birding etc but a bit underpowered for astronomy.

Getting Annoyed With Short Sighted Authors.

This week started out with a sky full of cloud and no sign of it clearing ’til the end of the week. So… what does the average amateur astronomer do when the night sky isn’t being cooperative? In my case it’s been reading books, so what does todays blog title mean? Simply put, the books i’ve been reading are beginning to really annoy me! More small scope rubbishing by people who should know better. especially as the book has the words “small telescopes” in it’s title.

 

The book in question is “Seeing Stars-The Night Sky Through Small Telescopes” by Chris Kitchin, Robert W Forrest, which in itself is a very good and very informative book for beginners, with handy tips for the slightly more advanced. My issue with the “Authors” or maybe even the editorial staff (let’s not forget that editors have the final say on what’s printed) have decided that refractors of 4-6cm and reflectors of 7-12cm are only good for observing the “bottom of the dustbin(which is where you will throw it soon after buying it)”**. Annoyed… you bet i am.

 

Not only have the Authors/editors chosen to rubbish small telescopes, they also have had the nerve to say that 50mm binoculars with 7-10x mag are fine…. So without further ado, maybe the authors should tell all the owners of telescopes such as Unitron, RoyalAstro, Zeiss, Pentax etc, that what they have spent hundreds of dollars/pounds on are just rubbish telescopes, and that maybe they would have more success with a pair of binoculars. Personally i find that binoculars are good for learning constellations as well as picking up a few clusters etc along the way, but I wouldn’t have thought that my 50mm refractor at 100x mag, capable of viewing the bands of Jupiter etc would have deserved such a poor reputation.

 

I know i harp on about what small telescopes are capable of and indeed what they have done for science over the last 500 years, but sometimes i feel that todays experts who decide to put pen to paper, have truly forgotten about the history behind their topic. Both authors are Batchelors of sciences and “Fellows” of the Royal Astronomical Society, yet they allow such pre conceived rubbish go to print with their names on it. This is not the only publication to have such contradictory views. There are several books and authors along with hundreds of forum users, journalists, broadcasters and institutions, that believe a beginner in astronomy is better served by a pair of 7×50 binoculars. This narrow minded, uninformed and misguided view of small telescopes needs to change. Today’s refractors far outperform anything Galileo could fabricate and the recent popularity of Apochromats also speaks volumes about small scopes.. so why print such total rubbish? Still annoyed.. maybe the weekend’s clearer weather forecast might brighten up my mood a little.. and if it is clear i’ll be observing the bottom of my dustbin with a 50 or 60mm refractor.

 

**Seeing Stars-The Night Sky Through Small Telescopes-page 22, Table2.1

Old vs New Telescopes

A question i’ve often asked myself is this, are old telescopes better than new? In order to answer the question i must first make the question clear. By old telescopes i’m referring to scopes made from around 1950 to 1980, new scopes obviously come after the 80’s. For some the turning point at least in telescope quality, can be roughly set at around the time Tasco started painting their OTA’s red..

 

Through the 60’s and 70’s Tasco telescopes were affordable telescopes that did the job. They weren’t fancy super performance telescopes on the whole although certain models have gained cult status. Other manufacturers of this era could be split into two groups, the expensive performance models and the cheaper adequately performing models. These manufacturers were the likes of Unitron, Polarex, Pentax, Swift, Celestron(early) Royal Astro to name a few.. the alternatives were “department store” scopes from Tasco, Sears, Jason etc and were considered “starter” scopes.

 

New scopes on the other hand are plentiful, there are 4 main players in the “affordable” scope market that still produce 50/60mm telescopes, these are Meade, Celestron, Sky-Watcher and the long serving Tasco. The products supplied by these manufacturers vary in quality and price but by and large these scopes all have the same origins. Nearly all small refractors are produced in China, yet the variable quality isn’t really limited to cost or brand as we’ll see in a moment.

 

Celestron are considered a “good” brand, selling telescopes of every variety across a massive budget range. Either thousands for the latest Edge HD or pennies for their “powerseeker” range. This doesn’t necessarily mean that all their scopes are good, I’ve had problems with 3 out of 5 celestron scopes i own with one scope returned to vendor!. Two very different experiences with what is essentially the same telescope.. see below

 

 

These two telescopes are essentially the same, they share an optical tube. focuser, eyepieces, diagonal, objective cell, tripod etc, but….. the Celestron had to go back to the vendor.. Why? simply the telescope wasn’t worth the cost. The Zennox 50×600 on the right on the other hand was a massive improvement over the celestron offering. The Celestron came with a Cemented Achromat objective that suffered severe chromatic aberration and was reduced down to 32mm!, The Zennox is an air spaced achromat with practically no CA from its f12 objective with full 50mm clear aperture. Why are the two so different? why does the celestron cost more than double the money of the zennox? same gear supplied with each scope, so the only explaination is profit… What this means is that even “New” telescopes can’t always be relied upon to provide a good experience for the amateur. The cost of the Celestron was more than i paid for the Tasco 6TE-5 so the vintage scope looks like a no brainer.

 

Two nights ago i had the oportunity to test old against new, the Tasco 6TE-5 against the Zennox 50×600, and surprised i was… The Zennox far from being outclassed by the vintage Towa optics equiped Tasco, actually proved to be a real contender. Many people who own these vintage Tasco’s rate them highly, me too, the performance is good for such a small aperture. Yet, when it came to the crunch, if i had to pick one to keep over the other…… the Tasco would be the pick. It’s not just a slight edge (very slight) in performance, it’s also the “feel” of the scope. All metal parts on the tasco beats all plastic on the zennox, it’s just a quality thing. Don’t get me wrong, if i had to replace the Zennox with a new one because it was broken beyond repair.. then i would buy another. I paid almost double for the vintage Tasco but if the zennox was also Alloy tube, metal cell and focuser then i’d gladly have paid double for the zennox…. again these things are hard to quantify.. but in the war of old vs new, this battle goes to the oldies..

 

next time out will be old vs new on either 60×900’s or 60×700’s depending on which i grab first. The contenders will be a Prinz 550 60×910 vs Zennox 60×900, or Optus 60×700 vs Prinz 330 60×710. stay tuned.

 

 

 

Tasco 6TE-5

Today i received my Tasco 6TE-5 telescope shipped from the USA. Surprisingly the package arrived safely and without damage, more than can be said of other scopes i’ve received by mail. I have a fondness of 50mm telescopes that i occasionaly give in to. Most are really cheap and the Tasco cost more to ship than to buy at £18.99 and £20 for delivery. It may seem like a waste of money to some… but, scopes from the states seem to be in better condition for their age than UK items. This may have something to do with weather, or even the american love of small refractors. All i can say is, most UK astronomers either don’t like or don’t care about 50mm telescopes as they are considered too small or too badly constructed to make them a worthy purchase.

Overall the scope is in good condition, just a little yellowing of the white tube assembly and dew shield. The diagonal was a little dirty and has some surface scratches that are only visible under really bright light. The table top tripod is in good condition and works really well for what it is. I haven’t checked the eyepieces yet as i already have a good selection available. So it’s time for first light and a patchy sky to contend with. My favourites at this time of year are the Pleaides, the Trapezium, Jupiter and castor. These are all targets i have observed regularly and give me a good idea of what a scope can do.

To test the Tasco properly i did a side by side comparison with my modified Zennox 50×600, i also have the vintage Unicon to compare with which i’ll do on the next clear night. First target was the trapezium, 3 stars clearly resolved in both telescopes but the Tasco just seemed to have the edge. Sigma Orionis showed it’s triple nature clearly in both scopes and again the Tasco seemed to be just a little clearer. Castor was still low in the east and splitting at this low altitude was difficult both scopes showed a thin black line separating the primary and secondary, but both stars looked a little blurry and would merge into a figure eight blob occasionally showing the true seeing conditions. Maybe i’ll visit Castor again with the Tasco just to confirm it’s abilities at higher powers. Finally over to the Pleaides for a tour around the seven sisters. A particularly good test for 50mm scopes under urban skies are the three small stars northwest of Alcyone. The two most distant stars at mag 8.6 and 8.1 can prove difficult under urban skies unless seeing is good. Again both scopes handled the target well, and again the little Tasco seemed to be just a bit clearer.

On previous occasions the Zennox has proven to be a very good scope for what it is, basically a very cheap “department store” scope. I was pleasantly surprised at just how good a cheap modern telescope compares to a 1960’s Japanese manufactured item. A lot of 60’s Japanese scopes were made by Towa, Kenko, Carton and rebranded and manufactured to the vendors requirements. Changes made were usually tripod, supplied eyepieces, colour etc, but they all shared common objective lenses. Todays amateur astronomers know that if you buy a scope made by any of these companies,  you’re getting a good quality scope for little money. That said, prices of these “Vintage” japanese scopes is steadily climbing, despite the current love of Apochromats.

Northern Skies With a 40mm Telescope

Elsewhere on this site is a guide to blacking out a cheap telescope, the scope in question is a Celestron 40 TT-AZ. Out of the box it has to be one of the worst telescopes in production today!. I can say this without bias and through experience… so why write about it? simply because with a little modification it can perform. I own several 40mm scopes nearly all of which are 1960’s/70’s variable magnification scopes similar if not identical to the Tasco 4VTE. One of the scopes i bought had parts missing from the focuser/corrector side but had a perfectly good cemented achromatic objective lens. Can you see where this is going?

 

The issue with the Tasco4VTE clones is the loss of light through the magnification/correction stage, there are 3 lens stages and an eyepiece which all reduce the amount of light throughput. A focuser with diagonal cuts out the 3 lens stage allowing more light to the eyepiece thus giving brighter images and a wider range of magnification using other .965 eyepieces. The 40TT was ideal to use as a base for the Achromatic lens from the 4VTE copy. Luckily the lens dropped straight in and the focal length was almost identical, no tube cutting required. if anyone else is thinking of doing this, be warned… not all of these 40mm lenses have the same focal length. the variables are usually 400-430mm which all work on the 40TT OTA, but there are fixed magnification scopes like my Greenkat 40x 40mm which have a focal length of 480mm and cant reach focus in the 40TT OTA.

 

Under the sky the 40mm was a revelation, pinsharp stars and a much brighter view than expected. Star hopping was easy and most objects observed were readily lined up just by aligning the ota by eye. So how much can you see with just 40mm worth of photons? observed tonight with just 30 minutes under the stars were: Jupiter, both NEB and SEB seen as dark bands with 4 moons easily visible. Followed by a trip to Gemini and Castor a clear split with clear black line between the primary and secondary, using a SR4mm giving approx 100x mag. Orion was next, the trapezium giving up 3 stars but my sky is washed out by moonlight tonight so maybe under darker skies i might get all four stars, unlikely but i’ll keep trying. Sigma Orionis easily showed it’s triple nature with a 6mm eyepiece, very delicate stars clearly defined just slightly dimmer than seen with a 50mm scope but still a good result. I must point out that these observations were made using the stock tabletop tripod, plastic diagonal and eyepieces, the SR4mm was from another scope. The main reason for using stock items was due to weight. all of my other .965 gear is vintage and therefore heavy and caused balance issues with the tabletop tripod. Maybe i’ll fit a Dovetail and get it properly mounted for it’s next outing.