21 replies to this topic

[natwin]

I'm in the market for a portable high end refractor for AP and would love to hear people's opinions about various options. I'm sure they'll be diverse and passionate.

 

My constraints include a 120-140mm aperture, a native focal length of 850-1000mm, compatible flattener to cover full frame (42mm diagonal) camera, compatible reducer for a 600-700mm focal length option, excellent color correction, tight peripheral spot sizes, and as light as possible. It will be used for AP 80% of the time and for visual the other 20%. Ultimately, I'm looking for a "lifetime" refractor in this focal length range.

 

Options I'm considering, in no particular order, are:

Tak TOA130NFB

Tak TSA120

Tec 140ED or 140FL

AP 130 GT or GTX

Others?

 

The TOA130 meets all the optical criteria, has a full range of native accessories, and is reasonably available. But it is heavy, awkwardly balanced, and the least portable of the mentioned refractors.

The TSA120 is lighter and more compact, but perhaps not as well suited for AP with a full frame camera given its smaller focuser?

The TEC140 has a nice aperture to weight ratio and a great focuser, but the ED version is corrected more for visual than photography and it seems the jury is still out on the FL version. Also, the TECs have a long lead time.

The AP130 is basically unavailable.

Perhaps there are others in this category that are a optical quality match for AP?

 

What would be your choice for a lifetime refractor for predominately AP?

 

[reddog1972]

Have you considered the Stellarvue SVX140T at a native f/6.7?  They make both a dedicated FF as well as a 0.74 FF/FR and will illuminate a full frame chip.

Light, high quality and much shorter wait times than some you've listed above - I hope to take delivery of mine sometime next month.

[bobhen]

You can get a Takahashi TSA 120 with a 3” Feathertouch focuser from many retailers. The TSA 120 will be the lightest and of course has superb optics.

 

Stellarvue offers their SVX 130 triplet but is weights slightly more than the TEC 140.

 

The AP 130s are very attractive (fast, light, compact, quick to cool, etc.), maybe consider running a wanted ad for one – but you will pay.

 

A Tele Vue 127is might be a consideration, if it meets your camera requirements. At 15.6 pounds they are very light, native flat fields as well.

 

If producing stunning images were a primary goal, I think I would choose the TOA 130 with it absolute best in class color correction and find a way to deal with the weight. And of course the TOA is a fantastic visual refractor as well. A sturdy mount for imaging and maybe another lighter weight mount (without the need to setup a GEM) like the alt/az DM6 for visual might be a consideration.

 

Good luck.

 

Bob

[natwin]

Have you considered the Stellarvue SVX140T at a native f/6.7?  They make both a dedicated FF as well as a 0.74 FF/FR and will illuminate a full frame chip.

Light, high quality and much shorter wait times than some you've listed above - I hope to take delivery of mine sometime next month.

It is a scope I've looked at and very appealing, at least on paper. It's relatively new though, and there's very little in the way of user experience available. If you post a review when you receive your copy, it would add to the wealth of information here on CN.

 

 

You can get a Takahashi TSA 120 with a 3” Feathertouch focuser from many retailers. The TSA 120 will be the lightest and of course has superb optics.

 

Stellarvue offers their SVX 130 triplet but is weights slightly more than the TEC 140.

 

The AP 130s are very attractive (fast, light, compact, quick to cool, etc.), maybe consider running a wanted ad for one – but you will pay.

 

A Tele Vue 127is might be a consideration, if it meets your camera requirements. At 15.6 pounds they are very light, native flat fields as well.

 

If producing stunning images were a primary goal, I think I would choose the TOA 130 with it absolute best in class color correction and find a way to deal with the weight. And of course the TOA is a fantastic visual refractor as well. A sturdy mount for imaging and maybe another lighter weight mount (without the need to setup a GEM) like the alt/az DM6 for visual might be a consideration.

 

Good luck.

 

Bob

The TSA120 has been on my short list for a while. Great optics, though not to the degree of the TOA, light weight, and not too expensive. The big "but" is that the 35FL field flattener for it only produces a 40mm corrected image circle, thus truncating a full frame chip.

 

As for the SVX130T or 140T, see my comment above.

 

I put my name on the wait list about 3 years ago for an AP130. By most accounts, I've got another 7 years to go, if ever. Can't wait that long.

 

Finally, the TeleVue 127is is a petzval design and the native focal length is a little short for my intended FOV. It would be, however, better than the FSQ106 for my purposes.

 

 

So a couple of questions for the community: Does the TOA130 require additional weights on the tube to counter the very front heavy objective? In my case there would be a filter wheel, OAG, and full frame camera on the back end. Second, why is the TAK 67FL not listed as an option for the TSA120 when all the other accessories seem interchangeable with the TOA? Has anyone tried a 67FL on a TSA120?

[teashea]

It sounds like you are approaching the issue from a good perspective.  You know what you want and you know the technical issues involved.

 

I suspect that the biggest issue you will face is finding one.  There are almost no quality refractors available in the US.  This is particularly true of Takahashi telescopes.  I had to purchase my last three Takahashi telescopes from Germany and Japan.  I would rather purchase them here - Takahashi America is such an excellent organization - but there simply are none. none.  

[Chris Ryan]

Might not be quite the correct focal lengths, but what about the APM LZOS 130/780?

[natwin]

It sounds like you are approaching the issue from a good perspective.  You know what you want and you know the technical issues involved.

 

I suspect that the biggest issue you will face is finding one.  There are almost no quality refractors available in the US.  This is particularly true of Takahashi telescopes.  I had to purchase my last three Takahashi telescopes from Germany and Japan.  I would rather purchase them here - Takahashi America is such an excellent organization - but there simply are none. none.  

The pandemic has no doubt strained supply, while the demand has gone up because... well, we're mostly stuck at home and astronomy beats TV any night. I'm not in a huge rush, I just don't have forever to wait for an AP130. I checked with TEC today and they told me there's currently a 12 month wait for the 140FL. That corresponds to the 12-14 months others have reported for a TEC. I assume a TAK would come faster, even from TAK USA. Then there the used market. Seems like a TOA or TSA comes up once every few months. I just want to be certain of the right scope for the job and ready to pull the trigger when one is available.

 

 

Might not be quite the correct focal lengths, but what about the APM LZOS 130/780?

Don't know much about APM, except they have a good reputation. A focal ratio of f6 is quite fast for a refractor. What's the color correction like on the LZOS130? Also, where are they made? Who sell them? I happen to live pretty close to the TEC facility in Golden, so the idea of driving over to pick one up or to have one serviced is very appealing.

 

I very much appreciate all the suggestions and info. It helps create a more complete picture of the options available.

[natwin]

Just looked up the APM LZOS 130/780. Looks like they also make a 130/900. German mechanics and Russian optics. Also looks like you'd have to order one from Germany. That's a lot of shipping if there's a problem. Still, I'd be interested to hear from people with first hand APM experience.

[DeanD]

Another option may be a CFF made-to-order 135mm or 140mm: https://cfftelescope...ducts/refractor

 

Approx. 9 months waiting time may be better than some other options.

 

Happy choosing!

 

- Dean

[Faber]

I had a LZOS 130/780: the color correction was superb and the portability was at the hightest leve. It’s difficult to choose. Perhaps for portability my short list could be tsa 120 and lzos 130/780. Good luck!

[k5apl]

I did not see a budget problem when you said "high-end", so I have an opinion.  Like you, I wanted a portable high-end refractor, and was fortunate enough to purchase an Astro-Physics 130edfGT.  The reasons I recommend it are:

1.  It is high-end:  Viewing from Hawaii in pristine skies proved this point, over and over

2.  It is portable:   I could put it in an overhead bin in airliners going to and from Hawaii with  temperature and pressure

                            controlled environment for travel.  Breaks down into 3 pieces.

3.  It is flexible:    The focuser can be upgraded to the larger focuser for larger cameras

4.  It is available: A Want-Ad will turn one up sooner or later

5.  It is small:       I used a Celestron CG-5 mount in CONUS, alt-az for overseas

6.  It is quality:    Astro-Physics telescopes are legendary

 

It is lifetime for me as long as I can use it.  After owning 128mm and 160mm refractors, this one at 130mm fits my observing needs.  It has allowed me to see the night sky in ways that I never could see it at home.    If the AP130edfGT is the telescope you choose, then you will find a way to acquire one.

Whatever your choice, I hope you will be content for a long lifetime.

Wes

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Edited by k5apl, 03 April 2021 - 12:46 PM.

[andysea]

I can only comment two of the scopes on your list the TOA and the GTX because they are the only ones that I actually owned/own.

 

The TOA is absolutely stunning from the image quality stand point. I never had particularly bad cool down issues like many complain about. My main complaint about it was the bulk and weight of the scope. It is heavy and large for its aperture. Some argue that's actually a good thing as it's over engineered. The TOA was my 5inch refractor while I was waiting for the GTX.

 

The GTX is equally good as far as I can tell but it's a lot smaller and lighter. I believe that technically the TOA is better corrected.

The other pluses for me are the Quad TCC and the fact that it's a faster scope.

 

So I find the GTX a bit more friendly for portability and ease of mounting/dismounting.

 

In the end they are both amazing instruments.

[payner]

Given the lens design of the TOA (modified Cooke), the lenses are very widely spaced. Hence, superb correction, requiring a robust lens cell to hold those lenses over a wide spacing so as not to move out of collimation. To reach the level of near perfection in correct, SA to a point virtual nonexistence, requires the heavy lens cell. I subscribe to a preference for a robust OTA in general for maintenance of optical alignment/rigidity.

 

Randy

[natwin]

It seems without question that the AP 130GTX is by far the best, of all the premium refractors in the 130mm range, for portability and travel. The clear problem is availability. At this point, only a used one would be an option. While I'm certainly not averse to buying used, the timing is up to the winds of chance. As a consequence, I've settled on the TOA130 and TEC140 as the most likely options. The relative availability, extensive selection of dedicated accessories, and color correction make the TOA a strong candidate. Only the size and weight for the aperture are holding it back. The TEC, while less available, is appealing for its larger aperture, and lighter weight, not to mention that the TEC facility is 30 minutes from my house. At this point, if either one came up near my location (I prefer local pickup), I'd probably go for it. I can't imagine being anything other than ecstatic using either of these fine instruments.

[natwin]

The one thing I'm still trying to get some first hand information on is whether the improved color correction of the TEC140FL is worth the wait, as I'd almost certainly have to buy a new one. I understand for visual, the differences between the 140ED and 140FL is spitting hairs. There is, however, relatively little chatter from people who have used both scopes for AP, in particular with a full frame camera. Also, TEC doesn't publish spot diagrams for their scopes with flatteners or reducers, so a direct comparison with the TOA isn't possible.

 

If anybody has experience using both the TEC140ED and TEC140FL for AP with a full frame camera, I'd love to hear your thoughts on the comparison. I recently contacted TEC and they told me the FL "has much better color correction" than the older ED version. I've seen the "Wings of Strehl" diagrams that support this, but haven't heard any first hand accounts.

[Jared]

I own an AP-130 GT/GTX (meaning a GT with a GTX focuser) and the appropriate field flattener. It does a great job with a full frame camera. Solid choice if you can find one used. In fact, it would be my first choice of those listed, just a little harder to find. 
 

My second choice would be the TEC in fluorite. I probably wouldn’t choose the ED version for 80% photography. Great scope, but really oriented to visual use. I have never owned a Tak scope, so can’t say one way or another. The Stellarvue offering is simply too new for me to recommend at this level. The TeleVue’s are great, but I think a step below the AP, Tak, and TEC offerings. 
 

Last thing I’ll mention, not to complicate your math, but it’s worth giving a little thought to... I’m not sure what camera you are planning to mate this up with, but as pixel sizes get smaller and smaller every year, you may find faster scopes like the FSQ are actually a really good match as well. You could get the benefit (for some subjects) of a wider field without actually giving up much, if any, resolution. Of course, you can buy reducers for many of the scopes listed as well, so an FSQ is not the only option for a fast scope, but it’s something to think about. Even full frame chips these days have pixel sizes under four microns, so even something like the AP-130 at its native focal ratio would be sampling at just under 1” per pixel, and that trend is likely to continue.

[natwin]

Jared, thanks for your insights. I will certainly keep my eyes open for an AP-130, but they seem the most rare of breeds. Also, I have considered the FSQ, as it would be a much simpler setup for AP, not requiring a flattener and all. But the focal length is a little short for the targets that interest me when using a full frame camera. And the bigger triplets make for more versatile visual scopes, on the occasion I do visual. As for the camera, I'm currently using a Canon 5D2 and also a Sony A7R4, but have been holding out for the elusive Atik APX60. Latest word is a year from now, so may go with a QHY instead. And yes, the trend is certainly in the direction of ever smaller pixels.

 

I actually print some of my AP work on wide format Canon and Epson printers, so sticking with full frame, as opposed to smaller formats, benefits print quality. So I've kind of worked backwards from targets of interest, to format and resolution requirements for printing, to appropriate focal length ranges. Fortunately, a lot of nice refractors fall in this sweet spot. Unfortunately, they can be hard to come by.

[base16]

Most of what I wanted to say has been said by @bobhen above. I have in fact owned all of those scopes now or some time in the past.

 

Given your criteria, I would suggest jumping on a TSA-120 if you see it on the used market. The newer ones come with a Feathertouch already installed straight from Japan. Only call out here is that at F7.5 you'll be wanting longer exposures. The reducer for these scopes are not cheap. But it does check all your criteria and in fact you can even order new and get it much sooner than a TEC or an AP.

[alan.dang]

I have owned the Astro-Physics AP130EDF, Takahashi FOA-60Q, TEC APO110FL, a Questar 3.5 1/10th wave, Vixen VSD100 and Televue Pronto.

All of them live up to their well-deserved reputations.

The first thing to ask yourself is about the weight. The 130 EDF is not a heavy scope for its class, but to me, it’s a night and day difference between the 100 or 110mm class to the 130mm class in terms of convenience. The AP gives me the best performance of my gear but it definitely crosses the threshold in a way that the TEC110FL did not.

All of them are lifetime scopes. My bias is that while you have the energy to carry a heavy scope, do it. If the TEC 140FL is in your budget, start off with that and then work down over time.

[edif300]

So a couple of questions for the community: Does the TOA130 require additional weights on the tube to counter the very front heavy objective? In my case there would be a filter wheel, OAG, and full frame camera on the back end. Second, why is the TAK 67FL not listed as an option for the TSA120 when all the other accessories seem interchangeable with the TOA? Has anyone tried a 67FL on a TSA120?

No. TOA don't requiere additional weights. Its a front heavy but can be perfectly balanced with no additional weights.

TSA-120 has 2.7" focuser and TOA-67FL needs a 4" focuser, I think it could perform very good (I didn't check this) on TSA-102/120.

[fate187]

Well, if you consider an LZOS 130/780 you are in for a treat . I have the slightly smaller 123/723 version of that scope coupled with a 3" FT. This is such a nice little scope and quite fast at f/6. There is the Riccardi reducer and flattener for APM scopes. The reducer is 0.75 bringing the 130 below f/5. The compact nature of the scope will also make it easier to handle on the mount. Importing from Germany shouldn't be too much of a problem, because APM and the like are familiar with shipping large telescopes around the globe.

The other scope 130/900 you mentioned is in fact a 130/1200 f/9 telescope, mostly used for planetary astronomy.

 

Regarding CFF 140, last time I looked there was one available at teleskop service, but pricey, compared to TEC in the US. There are dedicated full frame flatteners for CFF scopes.

 

And finally my opinion on the TEC140ED. I think pictures on astrobin and the like speak for themselfs. It delivers very tight stars with the dedicated flattener or 0.9 reducer. The tuning of the ED-version towards green in favour of visual performance is is of no issue if you use the dedicated flattener from TEC. Out of the box the FL-version does have an advantage on stars in the blue part of the spectrum. But that's is common internet knowledge. I can only speak for the ED here.

 

best of luck with your choice.

[andysea]

No. TOA don't requiere additional weights. Its a front heavy but can be perfectly balanced with no additional weights.

TSA-120 has 2.7" focuser and TOA-67FL needs a 4" focuser, I think it could perform very good (I didn't check this) on TSA-102/120.

That Is correct. The only one that needs a rear weight is the version with the 2.7" focuser which in my opinion is more suited for visual. 

The 4" focuser and the 67 flattener are so massive that essentially they act as a counterweight for the front cell.

Edited by andysea, 09 April 2021 - 02:06 PM.