Refractor people - unbiased opinion please

[glend]

I am considering one of two modified Achro refractors:

The Vixen NA140SS, which uses a 4 element objective (Petzval like correcting lens at the rear).

Link to description and specs here:

http://www.optcorp.com/vx-5868-na140ss-neoachro-refractor-w-dual-speed-focuser-tube-rings.html

and the iStar Asteria 127mm R30, which uses its longer FL and more exotic glass to reduce CA.

Link to description and specs here:

http://www.optcorp.com/istar-asteria-127mm-f12-r30-refractor.html

Both of these scopes have good reviews online, and are similiarly priced and will fit within my mount payload capacity just fine.

I'd like to hear from anyone who has one of these scopes, or is familiar with them through research.

The scope will be primarily visual use, but I will be trying to get into some basic imaging. Planetary is assumed, I have a big dob as well for DSO work. Both of these refractors have their strong points in my view.

And finally please, I'd rather not hear from the ED APO thought police. Thanks

[h0ughy]

well if they are the rules then go the vixen

[PlanetMan]

I can speak from first hand experience with a NA140

At the outset I have to say that I love Vixen products and as such really wanted to like the NA. In many respects it is a remarkable scope which looks nice and is amazingly light for a refractor in its size and gives good widefield.

However, you have to keep in mind it is primarily made in China with some final assembly and QC in Japan. The optics are 100% made in China. This is not a point of discrimination because so are the optics in the Istar. But you should be aware that Vixen makes two streams of refractors - one stream is 100% made in Japan and then there are the hybrid manufactured refractors such as the NA I just mentioned.

I earnestly tried to like the NA but the clincher for me was the planetary performance which I found awful especially for a 5.5 refractor. The final straw was the ultimate side by side comparison of petzval design scopes and thus "quantity" represented by the NA140 with 5.5 of glass versus "quality" represented by a Televue NP-101 with a mere 4 of top notch glass and all of Uncle Als pride in refractor design.

The result was a no-contest.

With respect to planetary the 101 didn't just blow the Vixen away but blasted it out of the city. This I didn't find too bad as it is easier to make smaller than bigger refractors and the 101 is more than double the price so for that kind of money it had better perform. Unfortunately, the real disappointment was despite the Vixen having all the extra aperture there was nothing in terms of DSO's etc that the NA140 could resolve that the NP101 couldn't also pick out even though it only had 4' of glass. So it was no contest as the NP101 could do everything and more than the 140 and yet was a third of the size (although more than twice the price)

For these reasons and the excellent reviews I have read (read the Neil English reviews in particular) I would recommend the Istar

[MortonH]

The latest version of the NA140 is made in Japan and is supposed to have better optics. Haven't seen any reviews yet to verify this.

[PlanetMan]

Sorry to disappoint but the assembly process has had quite a strange back in forth as first being made in Japan, then over to China, then back to Japan, then back yet again and then finally the half half. However, with the exception of the original NAS (ie 120, 140) when Vixen still used the green colour on the focuser the glass is made in China. Where the glass is made is not however a proper reason to dismiss it as no-one can get a straight answer out of Televue where their glass comes from other than it is very good

[MortonH]

Flashdrive has a new one. Maybe ask him...

http://www.iceinspace.com.au/forum/showthread.php?t=115262

[brian nordstrom]

:) I have an Istar 127mm f8 achromat and its the best refractor I have ever looked thru , for a doublet and if the R30's are all they claim ( as many people do ) they would be very good indeed .

But yes the Vixen is a nice scope , but I would put my money in the R30 f8 if all out visual correction is your goal as these perform like an f12 instrument .

But then there is the weight issue , from what I have heard the Vixen 140 is quite light but the 127mm Istar is very soild and well made and quite heavy so this brings us to the mount , what are you looking to use ?

Brian.

[MattT]

If it's a Planetary refractor you want then the choice is easy. The Istar 127 R30 will act like a 5" f15 in terms of false colour, or lack of colour. The Istar comes with a Moonlite as standard, or Feather Touch, focuser and are built like a tank.

If you want to wait for a little while Istar are bringing out a new tube which is lighter and has a retractable dew shield.
The Istar will be more expensive the the Vixen is the only downside.
Send Mike Hardin at Istar an email asking about the new tubes. Mike always answers questions. Istar is a fantastic company to deal with from my experience with them. The only downside is shipping and import taxes, which is why I built my own scope using an objective from Istar.

Can't comment on the Vixen but would think that at half the FL, CA would be an issue. I went from 6" f8 to 6" f12 and the difference in CA is huge, almost a non issue in the f12.

Matt

[Kunama]

I tried to find information on the origin some time ago, every source I found indicated that the NA140SSf was of Chinese origin, the new NA140SS is made wholly in Japan. Just curious how did you came by this info?

I've spoken to a friend in Japan who has dealt directly with Vixen Optics and also said this scope is Japan made. (Edit: in the end I went with a Tak)

[PlanetMan]

Same source

I will make this comment that if you are interested in one of these refractors then 1) If you can find an original (green focuser) - get it immediately (this is the original glass) or 2) If you want to try something unique - get it immediately

The NAS are an innovation gamble by Vixen which has often been described as neither fish nor fowl - unfortunately this has translated to mediorce sales and it seems like a toss up every 18months whether they will even continue with them.

The real problem is making petzvals is very hard and trying to meet the QC standards while keeping the price down has seen this contorted history and huge challenge for Vixen. It is easy for Televue and Takahashi to make petzvals as they A) Don't make them as big and B) Charge the price of a small car for one. The real killer for the NAs are all the big glass 5' budget APO and now - ironically - everything Istar - they have made a huge impact in the market - more so than DG

For these reasons I recommend getting one (if they hold an allure) as I suspect with the changing market they won't be around for much longer (new). Originally there was a 120 and a 130 but the 140 has only lasted because it provided big glass at an irresistible price - but even that is under attack from Istar with scopes like the R30 - Again I strongly recommend folks read the reviews by Neil English who is a very modest and measured reviewer.

[Logieberra]

I saw this YouTube video some time ago, but was waiting for the right thread on here to share it. It's a rare view into the production of Vixen refractors. In what country? Who knows. You experts can debate that. I just like the vid, with its funky Japanese diagrams and quirky music, as you'd expect :)

Watch "THE MAKING（２０３）天体望遠鏡ができるまで" on YouTube
THE MAKING　（２０３）天体望遠鏡ができるまで:

http://youtu.be/QKtyIlgc6FI

[casstony]

AFAIK it would be within the law to import a tube/focuser and an objective separately (say 3 weeks apart), keeping both shipments below $1000.

[glend]

Thanks folks for all the comments. I have studied the review by Neil English and that did get me excited about the iStar.

I have fixed up the links in the original post so they work now (sorry about that).

I posted this thread over on Cloudy Nights as well, simply because there is a much larger catchment of modifed Achro users over there.

I haven't been able to find out how much the iStar Asteria weighs (yet), but assumed it was close to the Vixen. If it's over 20+ lbs then I will have a mount payload issue so I need that information. Will check the UK website.

Keep it coming, I find the views helpful.

[Kunama]

Great video Logan, thanks for posting ( yes it is the right thread, was it a long wait?? )

[Shano592]

It is completely legal to do this.

The only downside is that you would have 2 lots of shipping charges, and it may be just as cheap to pay the GST and Duty, and get it all sent as one.

But yes, definitely not illegal. If it can be separated, there is nothing wrong with that.

[MattT]

When I looked into buying an f12 150 Istar achro it was about the same to buy it complete as brining it in in bits. As DIY is my thing, and the fact that Aluminium tubes are readily available in the sizes I needed, it ended up being 1/3rd the cost to make my own....easy decision for me.

Glen I have seen your CN thread and BillP does make a good point on the 120 ED Skywatcher, a bit more expensive but after shipping etc it might work out pretty much the same price :question:
Matt

[LewisM]

Vixen FL102S.... SUPREME and sublime.

I just sold mine to fund a Takahashi. Madness.

As to the choice of the 2, it depends on the NA - if Japanese hammertone green as mentioned, GRAB it. If Chinese "f" suffix, still a good scope, but...

IStar... NICE stuff!!!

DId I mention Vixen FL102S? :)

[MortonH]

Had a quick look at Neil English's site. The iStar is a long scope. Would be ok for visual but tricky for imaging.

By the way, the mount he's using in his website pictures:

http://neilenglish.net/my-adventures-with-an-istar-asteria-127mm-f12-refractor-part-ii/

is a Skywatcher SkyTee 2. I had one for a while and it is very, very sturdy (with a good tripod). Don't underestimate the mount that would be required for this scope!

[FlashDrive]

Well...I just came across this thread.......

Most of you know I have a NA140SS if you read my Sig'.
Mine is about 4 months old.....I can still smell the new paint in the Dew Shield.
This Model is Made in Japan....how do I know ....all the literature that came with it...states....Made ( exclusively ) in Japan by Vixen Optics....and even the supplier I got this through was emailing Japan ( I have proof of this )..as I had to wait nearly 2 months while a batch of them were being made.
In fact ...all the old NA140SSf Models were NO LONGER available....all new stock was sold.....

The New Model released now is the NA140SS ...Made in Japan.
With new ' refined Optics ' and the latest in modern Broad Band Coatings.
Several were shipped in for Aussie Customers .....3 were already ' SOLD ' ... 1 of which was mine.... the rest went into Stock.

I spoke by email to one of the other buyers ( while we were waiting for our Scopes to arrive ) to keep up with the progress of arrival....anyway he got his before I did ( I was next in line )....he was so impressed with his purchase ( he also owns the earlier NA120 Model )....he had nothing but praise for it's performance, Quality of Build and Optical Goodness.

I got mine about a week later ....and I have to say I love it.....everything about it suits my needs. I've looked at Jupiter with it ( using a FK Filter )...great views ( easily see the bands and all the moons ) using a Tak LE7.5mm and Saturn ....you can see the separations in the rings.

My real ' WOW ' moments have been looking at M42 ....it is just gorgeous, I can see 4 and a hint of the 5th Star in the Trapezium and the Nebula just ' sprays ' out like a set of ' wings '

M7( open cluster ) is a nice target to view, along with Omega Centaurus,
M45 ..Pleiades another.....I can go on...!!
I realize this Scope is not for everyone tastes...but for me...a large excellent made Refractor like the NA140 is a winner IMHO.

Flash......

[PlanetMan]

Yep - mine had labels clearly stating it was made in Japan too

Likewise - the manual and box stated it was made in Japan as well and the coatings and OTA was all in good condition

However, simply because a manufacturer lists this doesn't mean it is exclusive merely it satisfies a certain percentage for that claim. For example, Televue don't actually make glass themselves but their refractors are clearly labelled as made in USA. It is the way of manufacturing in the world that they subcontract to someone else and them assemble themselves - which satisfies the made in usa ratio for the providence statement

Anyhow, it shouldn't make a difference where something is made but rather how it performs - for my two cents worth I had rare opportunity to try both at the same time - there is a lot to be said for these NA as they produce a stack of big glass at an unbeatable price. However for me the NP101 won the contest easily - however - the key point was that is also cost almost 3x more:P

[FlashDrive]

Just spoke to a Vixen Representative in Sydney... ' ALL ' Vixen NA140SS are made solely in Japan

The previous models which has the ' f ' on the end of the ' SS ' as this SSf were conjointly manufactured in Japan and China.

' ALL ' manufacturing of the newer NA1400SS is Japan made......period.

These were his words....Not mine....Phone him if you want.... his name is Warren
PHONE: (02) 9436 4360 .....

By the Way ...all the NA140SS that were imported at the time I got mine were 'SOLD'
Plenty of other people consider these as a worth while purchase....that speaks for itself.

and of course it won't be as good on Planets .....it's focal length is predominately for ' wide field ' deep sky viewing...which it excels at and with a flatter field and very sharp. I use low mag' eyepieces most of the time....17mm down to 40mm

As one owner of a NA140SS has said ..... Doesn't excel at everything, but does nothing badly, and in a small, lightweight package that is easy on the mount.....In fact, the Vixen 140 is a really superb all around telescope.....information from CN

http://www.vixenoptics.com.au/details.asp?id=MAS-046C2


Flash.....:D

[Profiler]

I had one of these Vixen NA140 as well but I wouldn't have a clue whether it was made in Japan or China or Timbuktu!

I think everyone has gone way off track as I do agree what counts is how the mechanism performs. In this context there are some big benefits about the Vixen which have been under-estimated and some disadvantages which - irrespective of whether it is made by Merlin himself - won't change.

The huge plus I found about the Vixen was its weight - absolutely amazing that something so large can weigh so little. It is probably the only 5 inch + refractor that you can easily pick-up with one arm - this has huge benefits in getting your backside and the scope easily outside in dark locations and on a relatively small mount - do not underestimate this factor - it is very significant

The bad side which everyone seems to gloss past except for Flash that you have to keep in mind is the optical design of the Vixen as a very fast Neo Achro - thus it is optimally designed for exactly what Colin wants which is widefield observing with refractor quality optics. There is no fluoro element in the optical design and instead uses a 4 lens design.

So planetary observing is not its forte and never will be. This is not a weakness of whether it is made in China or Japan but fundamental to optical principles in how optics perform.

Finally, trying to compare the Vixen to the Istar is an apples and oranges comparison as they are very different telescopes designed to do very different things and have different strengths. For what Colin likes observing the Vixen sounds perfect. However, if I were after something for planetary observing I would probably pick something with a longer fl:hi:

If you want excellent bang for your buck in terms of planetary observing a whole bunch of beautiful f11 4 inch achros are now available - I think you can pick one up brand new for $500 (OTA)

If one of these appeals you will however have to come to grips with owning a telescope exclusively made in China - and good product too boot as well in my humble opinion.

[Kunama]

Couldn't agree with you more Richard, horses for courses!!!!

Oh and there is no telescope making facility in Timbuktu, I've been there!! In fact you would be hard pressed to find a telescope anywhere in Mali ...... but I digress.

[Profiler]

It sounds like potentially a wonderful dark sky site:rofl:

[glend]

Thanks to everyone for their ideas and comments. I have had a talk with Istar and based on that I have decided to buy the objective lens set from iStar and build a scope for it over the coming months. This will bring my costs way down, teach me alot about optics, and utilise my dormant boat building skills to create a platform for the objective.

[brian nordstrom]

:thumbsup: Good choice Glen , but either way both scops rock .
Will you be joining Istar scope club ? hope so its small but like IIS here very friendly and helpful , ask MattT .

Do you mind telling us what you are getting ? and please , please keep us all up to date as this project progresses , I am sure I ain't the only one interested in this ,,,,
Refractors rule even my lowely Achromat ( by Istar ) ;). I hope to get east within the next couple of years and I will show what mine is capable of to any who are interested ,,, I will never sell it , like a few Perthites have seen receintly ..:lol: .

Brian.

[Satchmo]

2c on the subject of planets through refractors , from an owner of both a good reflector and an ED refractor who has been observing the planets for over 40 years .

I would recommend also putting a 6" off-axis stop on your 16" to give you effectively an unobstructed `apo' equivalent ( colour free ) to see how well a small aperture works on the planets compared to larger

I do like observing the planets and own an excellent 120mm ED refractor that is well colour corrected, but I wouldn't use it instead of my 14" Newt if the seeing is reasonable and I want to see loads of detail on the planets. 5" or 6" is just not enough light to get high enough magnification to see fine detail. A 6" will show you the red spot on Jupiter but a 12" to 16" will show swirls inside the spot and colour differentiation amongst the features.

There is more to the issue of the appeal of apparently sharper planetary views in refractors ( due to their not resolving the finer turbulence that a larger scope `sees' and marginally better contrast ) . They are not good at showing complex smaller scale and larger scale band detail due to inability to supply colour differentiation of features in the disc view.

The ability to show colour differentiation needs a larger exit pupil and this is where the extra aperture comes in. If you are using ( maximum ) 2mm pupil for this ability on a 6" you only have 75X ( too low mag for resolving detail ) but on a 16" it is 200X which is at the lower end of useful magnification for planetary observing . A 1mm pupil will be too small to show clear colour differentiation with any size scope - but it is more likely going to be needed with a refractor to get the magnification high enough ( ie 150X on a 6" refracator) .

Even when the seeing is not so good colour differentiation will show you a mass of features that are invisible in a smaller aperture which is operating at a small pupil showing essentially only shades of grey on the disc features and that is even on nights where the seeing is soft - the small telescope will show a soft disc with mimimal detail but the larger scope operating at a larger pupil ( which activates the cones in the eye ) may show a wealth of detail ( albeit soft ) due to colour differentiation of the features .

I hope I explained this point clearly enough .

[glend]

This thread started as a request for input on a choice of two possible refractors (neo achro doublet designs) and simply invited comment on those two, re a purchase decision. I had hoped to limit it so that it did not drift off or get highjacked (as they seem to do) into theory discussions on Achro vs APOs, or the other - and certainly the merits (or not) of reflectors was not a consideration.

Both the scopes were 'fit for my purpose' and I subsequently made a decision to go with iStar (well to buy the iStar objective and build the rest myself).

The rational for a refractor is mine, and no amount of masking a 16" dob is going to make it weigh less than 15kg, regardless of what might be done to make it a better choice. I love my 16" dob but it is big, heavy, and not easy to transport - all advantages that those two refractors offered.

[Satchmo]

It doesn't look like any one here has experience with the 5" F12 I30 objective and there are no spot diagrams on the site but I dont think you could go wrong as long as you accept that all achros will have some degree of false colour.

[PlanetMan]

It is good to see so much diverse input