M&S 80mm Refractor

M&S 80x400mm

Here we go again with yet another refractor review! This time a Marks & Spencer (large retail chain like Sears etc) 80mm Travel Telescope. M&S don’t usually sell Telescopes but like any other large Dept store they occasionally offer trinkets at christmas time. I’ve got to be honest i wasn’t expecting too much!. As usual this was an Ebay find, and for £26 used including shipping i wasn’t risking my fortune.

Now for a run down on basic qualities. It’s small! 14″ end to end with focuser fully withdrawn, The tube and dew shield are metal and quite well blacked out. Achromatic objective with coatings and the accessories as pictured. 1.25″ focuser (plastic) with the usual 45degree prism diagonal and a pair of Huygenic eyepieces of 20 and 6mm giving 20x and 66x mag respectively. The supplied finderscope (not pictured) is one of the best i’ve seen, 5x25mm achromatic fully coated all metal with rubber eyecup!

So how does it perform? well… the standard ep’s while perfectly useable are better suited to a longer focal length telescope. They worked just fine but added some chromatic aberration to the view. I used a couple of plossl’s to see if the CA was down to the short focal length of the tube and was glad to see an improvement. This means the telescope does have some colour fringing (to be expected) which was made less obvious by use of better quality ep’s.

The whole reason behind buying this scope was down to a serious error of judgement made a couple of years ago. When i first took up astronomy as a hobby i started out with binoculars and my first telescope with eyepieces was a Celestron Travelscope70. Loved it to bits but the Tripod was useless! a Celestron Astromaster AZ mount soon fixed things but i got bored of the short tubes lack of ability for higher magnification. So i bought more and more telescopes looking for the “one” that would do everything! The travelscope sat redundant in it’s bag for a number of years until i bought a Skywatcher 200p Newtonian, suddenly i needed a widefield lightweight finder! Ta Da… the travelscope found new purpose and armed with a 32mm plossl was a great finderscope. So what happened to it that would require me to buy this 80×400 telescope…. Errrrmmmm i gave the travelscope away to a friend… bad move! the next time i used the 200p i was lost. Is the 80 a good replacement? you bet it is.. The 80 has the same 400mm focal length but more light coming in, a 32mm plossl gives 12.5x mag and a tfov of almost 4 degrees. As i said.. a great finderscope.

Under the stars i wasn’t disappointed either, CA was about what i expected and Vega was a bright violet fringed ball of light. the moon was good with violet edge on the limb but crystal clear across the rest of the surface.The double cluster in Perseus was bright and pulled in fainter stars than the 70 could have, M45 was spectacular with pinpoint stars, visible nebulosity around Merope and a really wide field. The trapezium in Orion split to 4 stars without too much effort but splitting doubles would be much easier in a longer focal length scope. Overall i’m really pleased with the 80, it does everything the travelscope could, but better!

In conclusion, would i recommend it.. yes! the tabletop tripod is useable but not the best. The accessories are useable but again not the best, but i reckon a novice who bought one of these scopes would be satisfied with it’s capability and performance. As with all chinese (Synta) scopes there are variants available from other manufacturers. Pretty much any 80x400mm scope will probably be using the same objective as this M&S scope just styled differently and with different accessories. As a widefield scope it works, as a finder it excels, but if your’e looking for high mag planetary views i’d look elsewhere.

Skybolt 50×500 Refractor

The latest purchase as listed in the title is a Skybolt 50×500 refractor. Manufactured by Astro it’s objective is rumoured by many to be of good quality. I have only briefly tested this out under less than ideal circumstances, a slightly cloudy night but with enough clear sky to allow a brief (15 mins) test. So how did it perform…. read on.

Skybolt 50×500

Firstly the scope arrived with a little dust on the objective but no marking to the glass, a quick clean and a minor mod to the focuser back end, i fitted a vixen threaded 1.25″ adapter to the focuser tube and was ready to go. The odd looking Alt-Az mount worked surprisingly well, it held position and didn’t alter allignment when tightening the adjusters. there are no setting circles or markers for degree settings so all targets were found by eye the old fashioned way. The Pleiades always gets observing time everytime i setup a scope, so first impressions of the target are made against so many previous observations with so many different scopes i’ve lost count. I have to admit i was impressed by the contrast and by the number of stars visible under less than ideal skies, an ideal test for 50mm scopes is the number and clarity of the chain of stars running down from Alcyone. On nights of poor seeing this chain is invisible to 40-50mm bino’s, on good nights all of the chain stars are visible and tonight with “average” seeing and average transparency all of the chain was visible through the little Skybolt. The double cluster in Perseus was clearly defined but a little thin on detail with stars popping in and out of view with averted vision, a fine night will allow a better view i’m sure. Auriga’s clusters M36,37,38 were all visible with some detail but fuzzy centres which again will probably improve with better transparency. Fifteen minutes is hardly enough time to fully review a scope but i felt that under the circumstances the Skybolt performed admirabley, definitely a keeper.

The scope itself is really well built, all aluminium with no plastic parts. Even the odd Alt-Az mount is all metal parts with suitable 50’s looking grey paint. I’m not sure when the scope was manufactured as it doesn’t appear in any of the available “Astro” catalogues, from the colour scheme and accessories i would guess at late 50’s early 60’s. The original instructions have been chopped and glued into the lid of the wooden box the scope arrived in, so no further clues there… The manufacturers stamp mark confirms it to be of “Astro” origin and the quality of the accessories suggests good quality glass and good construction, i havent used the .965 accessories yet but will use them in future. Maybe a back to back with my Tasco 6TE is in order bue due to a recent house move all my astro gear is still in boxes waiting to be unpacked…. more soon.

Carton T610 60mm Refractor

Since i bought my first telescope i’ve spent many hours looking into all the various telescopes available both new and used. As you may expect the hundreds of reviews posted by others carry a lot of weight when the decision to buy or not to buy becomes the question, but an underlying truth comes to the fore and that truth comes in the shape of manufacturers to covet or avoid.

The big players in the modern market Celestron,Skywatcher etc are mostly branded Synta products which are deemed to be reasonable quality for a reasonable price. At the other end of the spectrum are the Ferrari’s of the telescope world with prices to match, Takahashi being the first to spring to mind with others like Televue and Explore Scientific in the mix.

The big players 40 or 50 years ago were Carton,Vixen,Kenko,Eikow,RoyalAstro,Towa to name a few, with Zeiss and Unitron heading up the “Ferrari” end of the market. Of course there were other “niche” brands like Questar etc but the quality of the above mentioned manufacturers is yet to be superceeded by Synta and others. This is unlikely as the small scope market has been reduced to either high end Apochromats or low end Dept store specials. Whichever way you look at it, the 60mm telescope has had it’s day but has left us with some extremely fine examples that mass production can no longer equal.

Used scopes can be had for very little money particularly the older smaller variety, which is where we come to my latest purchase. The above titled Carton 60mm has always been on my wanted list, along with other small scopes that are either too rare in the UK or too pricey (Unitron/Zeiss) to warrant an interest. Last week the Carton appeeared on ebay titled “Astronomical Telescope” with very little info but an intriguing mention of a long focal length of 1000mm… Could this be worth a look? Only one picture posted with no mention of manufacturer so the search began.

Heres the pic from the auction:

My immediate impression was 70’s Tasco with the black metal tripod legs and Alt-Az mount, but it looked too long. By the time Tasco went for metal legs they had also changed focuser knobs from metal to plastic which had me thinking it was a “bitsa” scope with parts from a couple of different telescopes. Knowing that the metal focus knobs put the scope into 1950’s- 60’s manufacture my search began.

Several manufacturers of the era Kenko, Vixen, Carton, Royal Astro etc all made long focal length 60mm scopes with most of them providing Objective lenses for other brands. So which one is it i thought…. a quick look through some old pdf catalogues gave me the answer i was looking for,  and i decided there and then that this scope was going to be mine… This particular scope is odd in that it has the right mount but as i suspected wrong legs! that is according to the catalogue pictures. The good news is that the legs are manufactured by Carton and are taken from the T620 EQ tripod, where my scope is only shown with wooden legs. The scope (i think) is from sometime around 1970-75 although the optical tube appears to be from the 60’s and didn’t change throughout it’s product lifetime. I’m only guessing at this as the catalogues available are 1965-71-75 and later. Carton scopes are rare in the uk and i didn’t want to miss this one. I won the auction and the Carton cost me the not so princely sum of £31 or 45’ish dollars! a bargain… but wait!! i hadn’t seen the scope in the flesh and had no idea of it’s condition, but for £31 i wasn’t too worried.

 

The scope arrived today, in it’s original box! with all accessories and the original instruction book. As you would expect my first act was to remove the dust cap to check the objective… perfect, clear glass with no blemishes… a big grin spread it’s way across my face as i had finally got my hands on a Carton 60mm and it’s in perfect condition. Now the wait for a clear night under which to put the carton through it’s paces, just the right time of year as the longer, darker nights are moving in. A report with more pics to follow 🙂

Skymax 102 Under the Stars

Last night i decided to see how far i could push the little Maksutov! I usually stay within the golden rule of 2x aperture in millimetres for the mak thats around 200x, which isn’t a great deal for a long focal length telescope. After trying to split Epsilon Lyrae (double,double) with mixed results on it’s last outing, i decided to push a little further.  The result surprised me a great deal, i started out with the 32mm ep, then down to 15mm then 12mm all with good focus and beautiful difraction rings both in and out of focus. The 9mm also produced the goods and so i reached for the barlow.

 

Then came the surprise, using a Celestron 8-24 zoom and Revelation Astro 2x barlow i got the split on the double,double with nice clean break at around 20mm on the EP (10mm with the barlow) giving a theoretical 130x the only issue was a difraction ring on the northern of the two doubles that kept obscuring it’s secondary. This was either due to seeing conditions, the scope, the EP setup or me… so i decided to push further, the result cheered me up no end…. i wound the zoom down to it’s 8mm setting (4mm barlowed) and was rewarded with small round stars with perfect difraction rings, each double looking like a pair of fried eggs. The stars were spaced across about 80% of the fov, so i kept turning the slow controls on the skyteeII. That was when i realised i had jumped to 325x mag and the image was still clear! Don’t get me wrong.. the stars weren’t pinpoint, they were small round dots with a fine difraction ring but they were cleanly separated. Wide splits you could drive a bus through 🙂

 

I considered the fact that Lyra wasn’t at the zenith, and that Vega was twinkling in a far from steady atmosphere, i was impressed by the view at 325x using mediocre equipment. I would normally use dedicated EP’s not a zoom.. and i try not to barlow if i can help it. There was a little false colour thrown in by the barlow but nothing serious and the small dim star sat between the two pairs at around 150″ from the AB pair was still a perfect pinpoint. In my 60mm refractors the view at this mag would have been impossible to focus, there would have been so much blur that the doubles would fade into one blob of fuzziness. Time as usual ran out… i would have liked to have run the Celestron 80 refractor through the same test for comparison but overall i was impressed a great deal by the 102 mak.

Tasco 66TE 50×600 Refractor

The latest purchase has just arrived! For a while now i’ve been interested in these small (50mm) scopes. Not just because of their small aperture and reasonable(f12) focal length, more for the build quality you get with these scopes. As an example i’ll run through some of the basic differences between the pre 1980 telescopes and the later 1990 onwards examples.

 

 

The first and most notable difference is the material used, Aluminium tubes in earlier models replaced by plastic for later examples, same for objective lens cells and focusers. All the more expensive parts have been replaced with molded plastic!. In some cases this isn’t an issue, the Zennox 50×600 is all plastic but performs almost as well as my early Tasco 6TE.

 

The Accessories provided have also felt the budget squeeze. The early scopes have good quality all metal prism diagonals, the later scopes have plastic diagonals with cheap skinny mirrors. Eyepieces have also suffered, moving from glass lens components with all metal bodies for early scopes to plastic lenses and plastic/aluminium bodies.The new EP’s arent unusable.. you can still see quite a lot with them! they just aren’t in the same class as early EP’s. Tripods are a whole different ballgame! Early tripods came with wooden legs to reduce vibration and some degree of quality for a “beginner” scope. In the 1970’s/80’s The wooden legs were replaced with steel in Tasco’s case or aluminium tube with later models and this was the start of the downfall for small scopes during that era.The late models are provided with flimsy plastic and aluminium tripods that can completely ruin the performance of what may be a good scope.

There are only subtle differences in performance between old/new scopes with the exception of the Celestron 50AZ that was just total junk!. Surprising really as Celestron are considered a quality manufacturer compared to Tasco, whose reputation went south during the 1980’s due to the cost cutting mentioned above. Although some astronomers look back on the early Tasco scopes with bitter memories and gritted teeth, i’m sure the same people who now have age,experience and possibly a sturdier tripod would look upon these small scopes more favourably.

 

This is the second 66TE i’ve bought, the first has some damage to the coatings that wasn’t apparent when i bought it. The vendor had assured me that it was all in good order but dirty. Only when the dirt was carefully removed i found slight damage. I have tried the scope and it works perfectly but the coating damage makes it look worse than it really is. A neighbour is an optician who i asked about coatings, he said it would cost more than i paid for the scope to have it recoated… sad really. it’s only a tiny 1.5-2mm blemish that just looks like the coating didnt take properly. It isn’t obvious and takes a lot of looking before you can see it and it doesnt affect performance.. but i know it’s there….. you know what i mean…?

Luckily the new one that arrived today has just a little dust and no damage 🙂 the EP’s look clean and the diagonal is clean too. It’s almost complete.. sun/moon filters all nuts and bolts, the terrible metal legged tripod, but only the 12.5mm EP missing.. i have spares so i can make up the set. The weather looks favourable so it may get first light tonight. Which reminds me….. i must see about getting tube rings for the 50mm scopes so i can use them on the SkyTeeII. More soon…..

SkyWatcher SkyMax 102 Maksutov

My latest purchase is the SkyMax 102 made by skywatcher that i bought for the princely sum of £60.. bargain :). Brand new..the only downside was it had been dropped but i was assured by the vendor that it was still in good collimation. The day it arrived i threw in an eyepiece and lined up a red dot finder ready for the first clear night.

 

The Test

The clear night duely arrived 3 days ago and i got to test it.. using a 32mm plossl everything looked good and the view was almost exactly the same as my Celestron 80×900 refractor fitted with a cheapo 25MA eyepiece, so far so good. The OTA had been cooling for over an hour so i decided to try a few doubles, thats when i realised something wasn’t quite right!

Defocusing the stars revealed miscollimation that wasn’t present in the 32mm, that view was perfect with excellent symmetrical diffraction rings! i was using my trusty Celestron zoom EP which appeared to be okay from 24mm to around 16mm but then things got messy. At first i thought it may be “seeing” or not enough cooldown, so i tried the zoom in the 80mm refractor. The views were spot on.. so what was wrong with the Mak?

 

I spent the rest of the evening on the 80mm refractor, the Mak could be dealt with another time. The vendor had said the corrector cell (objective cell for us refractor lovers) had been removed to check for damage as there was a small dent in the lip of the cell. I wondered if there was any damage myself so i packed the gear away and took the Mak indoors to check it over. Disaster?? maybe… closely checking the cell revealed that it wasn’t sat straight, there was a 1mm gap on one side of the OTA where the cell sat flush with the tube at the end of it’s threaded section. This meant recollimating the Mak…. which for some reason is considered either unnecessary or a return to manufacturer situation by most people on the Astro forums. The devil on my shoulder said..”go on, it was only £60,.. it aint workin so fix it!”. I buy a lot of damaged/second hand scopes and i’ve seen all sorts of things that can easily be fixed or are a dead loss. I was hoping that the Mak that i bought primarily to be a travel scope would be fixable… first step is to find out how to get it apart without damaging anything.

 

The Problem

Consulting the internet and it’s vast wealth of info revealed one simple fact… Mak owners don’t like to mess with their gear! Eventually i found a collimation guide for an Orion Mak that closely resembled the Skymax 102. The rear cell has the same 6 screws (3 push/3 pull) and the collimation was akin to adjusting the primary on a Newtonian, all done by eye looking down the focuser tube. Great… in went the collimating tube, twiddle the allen keys and i managed to get a concentric reflection like the Orion guide had shown. All i had to do now was wait for the next clear night so i could star test it.

 

Back on the tripod and Polaris centred… the big reveal!… it was worse!! how could this be? so i twiddled the allen keys and got something like but not great. Back to the drawing board!

Indoors i decided that stripping the OTA down was now a necessity rather than an option. Off came the front cell, then holding the tube upright with the focuser at the bottom i removed the focus knob and then the 3 larger allen bolts. I had the backplate in my hands and now it was time to start measuring everything in an attempt to see where the misallignment was. just turning the backplate it wasn’t too obvious that the mirror was tilted, measurements made the tilt just over a millimetre on one side! thats why things were so messy and the tilted primary meant that the 1mm gap at the front cell was throwing everything out. At this point i was hoping the “drop” the tube had suffered hadn’t stretched the threads that hold the front cell. Measuring the OTA showed that everything was square as far as alignment was concerned so the answer must be a tilted corrector!

 

Noted all the symptoms, targeted the problem, now to see if it can be cured. The corrector cell is like those found in binoculars, a holder that the corrector sits in with a threaded ring holding it in place. Now onto the next problem, the cell “dent” is where the threaded ring screws out… Hmmmm only one way to remove the ring and that means knocking the dent out of the cell… with the corrector lens in place.. eeeek!! and trying to do it without ruining the threads! sounds like a nightmare but i had no option. I know that hitting a lens cell can make it go “out of round” so i needed to put it back in the OTA.. this would also help to hold the corrector while i hammer it.. sounds barbaric.. but i know how to be gentle when the need arises.

 

The Fix

A piece of wooden dowel, a good hammer, a workmate (portable workbench) and some spacers to keep the tube level. Now it’s time for the dirty work.. tap,tap,tap the wood was compressing, so i rooted out an aluminium drift and started again. It was straightening the dent but marking the threads, ah well… the threaded ring will cut some new ones on its way out.. almost there.. then i noticed something!, the ring isn’t sat directly on the lens.. Closer inspection revealed a rubber o-ring or seal between the ring and corrector lens.. and it wasn’t located properly!

I very carefully pushed it into place and i heard a tiny “clunk” sound. Was that the corrector relocating itself.. must have been! theres nothing else that could move. Back indoors and time for the sighting tube.. collimation was definitely out, but the opposite side to before. i carefully adjusted the rear cell ’til it was looking good.. now to wait for nightfall and hopefully clear skies.

 

The Result

The star test was great in the 32mm.. minor adjustment brought perfect diffraction rings.. then the jump to 12mm.. slightly out but again a minor twiddle and it was perfect.. i spent around 2 hours just around Lyra and Cygnus. The double double wouldn’t split.. 12mm gives 108x which wasn’t enough. In my light polluted environs i can cleanly split Epsilon Lyrae at around 130-150x with my 80mm refractor, i get figure 8 at around 120x. so i popped in a 9mm which gives 144x in the Mak with it’s 1300mm F/L, the result was a little untidy.. but the split was there!! success!! sort of 🙂

It was 1.20 am and time to pack away.. i had my allen keys in hand and should have done the final collimation there and then.. but didn’t. That’ll have to be tonight.. weather permitting.

 

Final Thoughts

The reason for purchasing the Mak was purely based on need of a good,cheap,portable scope that i could use for double stars and planets. Something with long focal length but compact size. My first thoughts were to go for a Meade ETX, High cost and mixed reviews put me off, others had reported all sorts of issues with the mounts and drives along with collimation issues. I had thought of the ST80 refractor.. but again short focal length was going to limit double star observing. The 102 Mak seemed to tick all the boxes, and it does now i have it collimated. Performance wise it’s almost exactly the same as my 80×900 Celestron. Using a 32mm in the mak gives 40x mag and beautiful views, the celestron with a 25mm MA gives 36x and is comparable to the Mak. The Mak does however show slightly fainter stars but only just. The Skymax 102/ F12.74 is really the equivelent to an 80mm F11 refractor. This is what i was hoping for in a travel scope. I did own a Celestron Travelscope70 for a while which was great until 100x mag which was about it’s limit. The long f/l refractors have always been a favourite so finding the same performance in such a small package has really cheered me up… now it’s fixed 🙂

 

I will probably set up a page with pics for the collimation side of things. There’s practically no info on these small maks other than the manufacturer blurb, so it may be of use to others.. stay tuned.

 

40mm Towa Zoom Telescope.

Last week i came across a 40mm Towa that looked like a smaller version of the 60mm Towa featured elsewhere in this blog. Bought very cheaply as i was the only bidder, the scope arrived and was in a sorry state. The 40mm objective (like all the others i own) is cemented not air spaced, but unlike my others this had been unglued by the previous owner!! Sadly the muppet had decided to pry apart the 2 lenses resulting in chipped edges and lots of balsam left in patches. A few minutes cleaning and the objective was almost useable, i say almost as when i tested it the view wasn’t as good as any of my other 40mm scopes. Now i have the choice of either buying Canadian balsam and reglueing the objective or attempt to foil space it… maybe another day.

The rest of the scope hadn’t faired much better, the focuser mount holes which are threaded to accept bolts are stripped, with various screws used in place of the original bolts. Shouldnt be an issue as i have Taps and dies and will eventually get round to sorting it. The mount as with all my other 40’s is the tabletop variety, all metal tripod with lockable yoke. The performance dispite the objective lense issue is fairly good, it looks like Towa have used the same design and quality of lenses as used in the 60mm version. As an added bonus the eyepiece on this scope provides a lower mag than the ep on the 60mm, they are interchangeable and so provide a wider choice of mags. Using the ep from the 60mm scope will provide a zoom range of 30-90x, which is almost the limit for the 40mm objective. I have regularly had 100x mag from the 40mm scopes in my collection, but beyond 100x things get a bit messy. Maybe clearer skies would allow greater magnification, something for the future but 90x is good enough for now.

Epsilon Lyrae Through 80mm

Tonight i was really pleased to split the infamous “double,double” with my 80mm, Yes… i know it can be done with as little as 60mm, but from my urban location with Lyra sitting  north east  barely above the top of nearby houses it was a treat. To give a better idea of the minor achievement, my target was only 26degrees above the horizon just emerging from the glow of nearby street lighting. 180x magnification split the C+D components cleanly, with A+B kissing with occasional visible dark line with averted vision. Add to this that because my time outdoors was limited, i only grabbed what was available in my garage which was pretty much OEM accessories. The ubiquitous 10 and 25MA eyepieces and correct image diagonal that came with my Astromaster 70AZ, along with a cheap 2x barlow were all i had to hand. My plossl’s and decent diagonal were tucked away nice and warm in the house.

The Celestron 80LCM optical tube has been a good performer so far and the super low price of £15 i paid for the optical tube has proved to be a bargain. Next light will give me a chance to use some decent equipment and maybe get a good split on the A,B pair. A quick look on the starsplitters site will no doubt provide a few more targets in that locale, with maybe a tour of Coma Berenices and Bootes while i’m out there.. time permitting as always.

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.