Takahashi FS 128 vs Takahashi TSA 120 vs Televue NP101

[Joves]

Hi all,

Ok, so I'm ready to buy a premium largish (well, larger than my TV-76) APO and have pretty much put it down to one of these three. I'd love to go for a 6 inch Tak but, aside from not having a mount that I'm confident it would deserve, paying more than twice the price for an extra inch of aperture I just cannot justify. Certainly not under the type of conditions which I observe.

So, I need your advice please. Each of these scopes have their pluses, so I guess it'll come down to what I'll be using it for. I'll start by saying that it will pretty much be purely a visual scope. There is the possibility I may occasionally hook my Mallincam up to it, but I really have no grand designs of getting into AP. So, let's just call it a visual scope. If it ends up being one of the Tak's, it will be mounted on my Skywatcher AZ-EQ6. If the NP101 wins, I'll mount it on my Televue Gibraltar mount with SkyTour and move the TV-76 to permanent placement on my Televue Telepod mount which, until now, has served me perfectly for travel and for mounting of my PST during the day.

As I understand it, the FS 128 is a fluorite doublet, better served as a visual scope than for AP, as it isn't as well corrected for CA as Takahashi's new triplet lenses. It is the largest of all three scopes, both in physical size/weight and aperture, and has a 1040mm focal length. I'm feeling this would make a great planetary scope, which I would definitely be keen to use it for, but not solely for this purpose. I'm ideally hoping for a great all-rounder.

The TSA 120 Super APO is a triplet with, apparently, practically no CA whatsoever. It is obviously a slightly smaller aperture with a slightly shorter focal length of 900mm. Another very tempting option, particularly when compared with the FS 128, however, this is purely going to be a visual scope. I'm asking myself, "Do I really need the optics of a triplet for visual when apparently the fluorite doublets give arguable better contrast?"... "Would I be better off with the slight increase in aperture of the FS 128?" AND "Do I really want to spend an extra $1000 on this than I can purchase an FS 128 for when it has a slightly smaller aperture and I'm not going to be doing any AP with it??"

Then finally, the NP101. For some reason, I've had a hankering to get one of these for awhile now. I'm confident it is a cracking telescope, having heard barely a negative word about it. Plus, I already have the Gibraltar mount, which it seems almost criminal to not have one of these sitting on. Also, the Gibralter, to me, is pretty much the ideal grab and go mount for visual observation. However, it IS only a 4" scope. I'm sure the Petzval Quadruplet optics are about as good as they come and would hold their own against pretty well any other scope, but I can just see myself wanting for a bit more aperture if I go down this route. Plus again, I'm going to be using it purely for visual, so is it absolutely necessary to have such a flat field?

To summarise, the aperture and cost are attracting me to the FS 128. The aperture is attracting me to the TSA 120. This one is pretty well on par with the cost of the NP101, which is attracting me because... Well, because it's an NP101.

All suggestions and advice would be greatly appreciated!

Thanks folks.

[Nakedgun]

If you can find a 128 when you are looking for one, then aperture wins this contest of high-end rigs, in my view. You will not be disappointed in its performance. I'm not familiar with your mount, however. The Losmandy GM8 will support one, though it will be shakey in any breeze, while the G11 is ideal, from my experience.

Good luck.

[ollypenrice]

I've used a Genesis on my Gibraltar and found it OK, but not over mounted at high magnification. Since planetary views are lovely on great apos I prefer a tracking mount. For widefield it doesn't matter and the push-pull simplicity is nice and Dob-like.

The big plus of the 101 is the short FL giving vast views of targets like the entire Veil, the Pleiades in context, the Double Cluster with Stock 2 etc etc. If you love this kind of view the 101 is the one! However, if you want to go deeper and  are not so fussed about ultra wide fields then you'd be paying a fortune for a photographic flat field which you don't intend to use.

I don't know the newer Tak triplets but I'm sure that both the old 128 and the 120 triplet would be great.

You haven't considered a TEC140 Triplet Apo? These really are quite something as well. Ours is fine on an NEQ6.

Olly

[ChrisLX200]

You've excluded a lot of suitable scopes by limiting the choice to the 3 mentioned, especially if photo performance is not a big issue. A lot of money goes into the design and construction of fast, photo-capable APOs that you would not reap the benefit of by using it solely (or even primarily) as a visual instrument. The NP101 for example, offers a very fast focal ratio combined with a flat field which makes it a great imager, and whilst it will perform superbly as a wide-field visual scope too, plonk a WA eyepiece in a longer f/l scope and the effect will be similar - at a big saving. Of the 2 Taks then the 120 is a nice light-weight scope and perfect for visual use. You wouldn't need the FeatherTouch focusser upgrade (which is available as an option on this OTA) unless you want to image with it.

I suggest you look wider though, there are many options open to you in this price bracket. For visual use then aperture rules - a camera doesn't care that much and will happily sit there collecting photons for minutes on end but your eyes are far less patient and many deep-sky objects will be disappointing despite the superb optics.

ChrisH

[Peter Drew]

I've had the pleasure of using a Tak TSA120 and it's hard to imagine a better 120mm telescope. However, I wouldn't spend such a lot of money on a small telescope for purely planetary visual use, aperture equals resolution and resolution is the requirement for planets.    

[Joves]

Thanks for the replies guys, they're very helpful.

David, I'm definitely leaning toward the FS 128. There is one currently available and the size/cost is appealing to me at this stage.

Olly, the NP101 is also very tempting. Would you think it'd be worth owning purely as a visual scope? Who knows, perhaps one day I might try my hand at imaging (never say never) but it seems unlikely at this point in time. I have neither the knowledge, skill or patience for it at this stage. I must say, the TEC140 looks like a great scope and has some great reports. However, there don't seem to be any australian distributors of this particular telescope, so the cost will blow out considerably if I purchase one and have it imported here.

Chris, I'm sure I've left out a HEAP of suitable scopes, mainly due to what is currently available to me. However, I'd love to hear what others you guys feel I should throw into the mix. This being said, I'd ideally like for it to be either a Tak or TV. Not hellbent on this, but it's definitely my preference.

Peter, so you'd advise to go for the FS 128 or are you suggesting I go for a lesser quality telescope than all I'm currently considering in lieu of as large an aperture as possible? Bare in mind, I do also own a 10" LX90.

Thanks again guys.

[ollypenrice]

Thanks for the replies guys, they're very helpful.

David, I'm definitely leaning toward the FS 128. There is one currently available and the size/cost is appealing to me at this stage.

Olly, the NP101 is also very tempting. Would you think it'd be worth owning purely as a visual scope? Who knows, perhaps one day I might try my hand at imaging (never say never) but it seems unlikely at this point in time. I have neither the knowledge, skill or patience for it at this stage. I must say, the TEC140 looks like a great scope and has some great reports. However, there don't seem to be any australian distributors of this particular telescope, so the cost will blow out considerably if I purchase one and have it imported here.

Chris, I'm sure I've left out a HEAP of suitable scopes, mainly due to what is currently available to me. However, I'd love to hear what others you guys feel I should throw into the mix. This being said, I'd ideally like for it to be either a Tak or TV. Not hellbent on this, but it's definitely my preference.

Peter, so you'd advise to go for the FS 128 or are you suggesting I go for a lesser quality telescope than all I'm currently considering in lieu of as large an aperture as possible? Bare in mind, I do also own a 10" LX90.

Thanks again guys.

For me the TeleVue would be worth it if you love ultra-widefield views. You can get the TV down to about 15x but if you are happy with the still considerable FOV the larger refractors would offer you then I'd go for one of those.

While I can't argue with Peter's physics or his expertise, I generally prefer the planetary views in our TEC140 to those of our Meade 10 inch SCT. There are nights when the SCT wins but more often than not I'd go for the TEC. The problem s that eyes are very personal things!

Be warned, I'm one of those crackpots with an irrational love of refractors!

Olly

[Plantins]

For visual use the fs128 is the way to go.

[Naemeth]

I'd go for the TEC 140 over them all for all but widefield views .

[Peter Drew]

I have at least a dozen refractors including a 102mm flourite, 127mm F15 triplet and a 220mm F 12.5 achromat, I still prefer the detail in my 16" SCT on a good night though a younger observer may well do better with the others.

[ollypenrice]

Ah, now a 16 inch is what you CALL an SCT!

Olly

[Naemeth]

Ah, now a 16 inch is what you CALL an SCT!

Olly

Super Cool Telescope?

Mind you, going to 16" of aperture weight becomes an issue, not 100% sure a AZ-EQ6 would handle it.

[Rainmaker]

Aaron, although I have just sold my TSA120 I would rate it ahead of the FS128.  The TSA shows no colour unless your eyepieces introduce it into the equation.

I ended up going up to the Mewlon 210 and for wider /quick views still have the FS60CB (which is a superb scope and easily gives 100X with a 3.5mm ep)

Although the TSA is incredibly sharp, I find that to view nebulae and fainter stuff like DSOs the µ-210 is much better.

The aperture difference between the 120 and the 128 is more than compensated for by the TSA's colour-free, super sharp views.  That is not to say that the FS128 is not a  great scope.

The Mewlon must however be allowed to cool to get the best out of it, once cooled the views are excellent.  I don't know the Televue scopes so no comment on them other than to say that I personally find 4" scopes too small in aperture for my liking. 

PM me re the FS128 if you want to know its history.

Matt

[ChrisLX200]

For purely visual use I would go for a large aperture (and high quality) binocular. From a dark site I could see more galaxies/DSOs using both eyes through my Miyauchi ED binos (20-30x, 80mm) than I could with a 10" LX200 using one eye.  There is something about using both eyes together where the result is better than merely adding the two images together. Recommend you try looking through a pair if you get the chance.

ChrisH

[ollypenrice]

For purely visual use I would go for a large aperture (and high quality) binocular. From a dark site I could see more galaxies/DSOs using both eyes through my Miyauchi ED binos (20-30x, 80mm) than I could with a 10" LX200 using one eye.  There is something about using both eyes together where the result is better than merely adding the two images together. Recommend you try looking through a pair if you get the chance.

ChrisH

Hmmm, I thnk this may vary from person to person. I have a lazy eye and don't find anything too spectacular happens when I use a binoviewer or large binoculars. Exactly what effect a binocular has on 'light grasp' is pretty mysterious. It certainly dosen't have the effect of doubling it. Close one eye and the view doesn't get dimmer. It's a difficult question. Some really love using both eyes but it doesn't do much for me, really.

Olly

[StarryEyed]

Lazy eye ! You lucky man I suffer from a lazy mind. Sometimes cant even be bothered to finish an

[StarryEyed]

TSA 120 Its versatile. I am trying to hold off buying one. I like visual astronomy always makes me smile. Nice and simple. I would buy one of those new FC100D if there came as a FC120D.

I hate choosing.

[dweller25]

I have a Takahashi 102 and a 128 - the 128 shows much more planetary detail then the 102.

Had a Mewlon 210 but wasn't impressed when I put it up against the 128.

Olly has thrown a 140 into the equation - definitely worth considering.

As Peter says - aperture rules - A good 10" Newt will beat all of the above.

[jetstream]

I have at least a dozen refractors including a 102mm flourite, 127mm F15 triplet and a 220mm F 12.5 achromat, I still prefer the detail in my 16" SCT on a good night though a younger observer may well do better with the others.

Now that,Sir,is a telescope!(16" SCT) Mighty impressive looking,I can only imagine!

[ollypenrice]

Sorry, but I don't believe aperture rules. It would rule if all else were equal, but it isn't. Not by a million miles.

Olly

[paulastro]

Ha ha Olly, that made me smile.  Spoken like a true refractor man!  More seriously, of course you're right.  My take on it would be that sometimes it does and sometimes it doesn't!.  I have to confess I love refractors, but my best view ever (in over 40 years) of Mars was with Peter's 16inch SC when we took it to Kelling a few years ago.  Anyone who knows me well will know how much it pains me to say this, ha ha.

[Stephen]

Mirrors are for shaving

[Naemeth]

Mirrors are for shaving

Lenses are for glasses .

[Stephen]

Lenses are for glasses .

 

[Naemeth]

 

I'm not being too serious - I've got 4 refractors, and only 3 reflectors .

Edited January 13, 2014 by Naemeth