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TV85 vs Tak FC-76DC vs Tak FS-60C


Stu
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I will do some more in depth reviews of these scopes side by side when I get a chance, but I did a brief comparison of them on the sun just now using my normal Lunt Herschel Wedge, Continuum filter and BGO's.

The surprise is... there is no surprise. Working up from the 60 which I bought as an ultra portable, go anyway, almost 'chuck in the boot' scope, I found this gave quite acceptable views with enough detail to be interesting but significantly off my experiences of the TV85.

It is the fine detail which is lacking, as you would expect given the resolution differences. You can see the same basic shapes and structures with the 60, but it is just 'softer', like it has a gauze over it compared with the others. There is nothing wrong with the scope, it is just that 60mm of aperture has its limitations. Given the 355mm focal length, I was using a 7mm BGO giving x50 which was around the max it will take whilst keeping the definition. It remains perfect in terms of the tiny size and ruggedness, and is easier to use now I have switched the dual speed focuser round and mounted it on an L bracket.

The 76 gives a very useful step up in resolution and brightness and would be more than enough to keep me happy. This is the idea as it is significantly more portable than the 85 because it is lighter and splits in half. It is also easier on the mount, and wobbles less. The dual speed focuser is quite nice, although there is a small amount of image shift so this is not the strongest part of the scope.

Finally the 85. As expected, this was definitely the strongest in all areas. Better definition in the fine detail, more granulation visible plus the faculae were better defined. The focuser is a lovely, smooth R&P which in someways feels lacking after using a dual speed, but in reality it allows you to obtain precise focus just as easily. That said, I am still keen to try a FT microfocuser on it.

Given that all three are top notch scopes, I'm not surprised that the fundamentals ie aperture are what is driving the differences in image quality, at least in narrowband solar.

The Taks are probably better optically than the 85, so it will be interesting to do a comparison of night time Astro targets too at some stage.

For now though, they each fill a niche for me. I know that for solar observing at home, the 85 is the best option, but for times when I don't have room or luggage capacity to take the 85, the Taks, particularly the 76 are plenty capable enough.

Once I get the FT for the Tak, I will actually have three complete scopes rather than the 76 being an add on to the 60. I will keep the short CSV tube and original focuser on the 60, then use the FT and the longer tube for the 76. Will post some pictures to explain this more clearly.

Stu

Edited by BigMakStutov
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Great report Stu,you exposed the fundamentals using those optically excellent scopes.The 120ED used here is about the most aperture that seeing conditions allow,with 200x being common and 250x "gravy" on solar.90% of portability is lost however.Your TV 85 must deliver fine views with good portability.

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Great report Stu,you exposed the fundamentals using those optically excellent scopes.The 120ED used here is about the most aperture that seeing conditions allow,with 200x being common and 250x "gravy" on solar.90% of portability is lost however.Your TV 85 must deliver fine views with good portability.

Thanks Gerry. The 85 does seem to be a very good mix of portability and performance for solar observing, particularly with the Leica. It proved itself again today, showing more granulation, faculae and fine detail than the 12.5mm BGO.

I didn't try the Leica in the 76, should work very well in there are f7.5

When I have some time, I will try to do some sketches showing the comparative views, might be interesting

Stu

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Really nice report! Now you have me wanting a TV85 as well....I cannot buy a 7th scope, can I?*

*The answer is no, if I want my girlfriend to talk to me :grin:

Despite a recent purge I seem to be back at 8 again (if you count the Taks as 2).

I'm sure your girlfriend does very well for shoes Matthew, so why not? :-)

There is a lovely TV85 in the classifieds at the moment which is hugely tempting. I do like the older shiny anodizing on the Televues.

By the way, have you bought yourself a Herschel Wedge yet ;-)

Stu

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  • 4 weeks later...

Bigmak, im tempted to buy the 76mm upgrade for my FS60c. In your opinion, what scope gives the best visual star fields to to the edges, the 76upgrade or the Tv85?

As much as i do love the super sharp stars in the centre 50% of the fov with the fs60, out from there they are not so great and actually disappointing. I assume its because its only f5.9, i assume the 76mm upgrade at f7.5 would give much flatter field and sharp stars in the entire fov?

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Edited by Pingster
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Hi Pingster,

Which eyepieces are you using?

So far I've only used the Tak FS-60c for solar so haven't seen issues with lack of sharpness towards the edge.

One problem I do often see with the smaller ED refractors is field curvature so there is a need to refocus between centre and edge. I suspect the 60 is just the same but will check and compare it with the 76 and 85 when I get a chance.

I have used a flattener (from TS) occasionally to solve this problem and it does work quite well.

From first impressions with the Tak 76, it is a lovely objective and seemed pretty sharp, at f7.5 I would expect the curvature to be less of an issue.

I was tweaking my Genesis again last night, and now that the petzval is properly placed, it shows a very flat field even with a 21 ethos.

I'll let you know what I find.

Stu

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Im using a TV 24mm pantopics. That eyepiece gives the least field curvature of all my eyepiece. During the day i do notice edge sharpness drops a bit, but its nowhere as distracting as star fields. Ill be interested in your findings when you try yours at night. Even with having to refocus between centre & edge stars, its my favorite visual finder as the stars are generally more consistent than any other finder in the centre of the FOV.

Just as a side note for anyone looking for a visual super finder, personally i find 80mm is better as 60mm does not quite show star clusters with enough detail. However finding a lightweight 80mm is tricky, hence my consideration of buying the 76 OG unit for the Tak.

Big Mak in your estimation. How much does the OG unit weight itself?

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Edited by Pingster
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Plz post a picture of it when you can. Bino finder! Thats epic

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Sorry to disappoint/mislead, when I mean bino finder, I mean using one objective from a pair of damaged binos, not a genuine bino finder.....

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BigMak. Do you know how to remove the empty part of the ota from the focuser block? As i am sure i read on a blog that it can be done so that you can achieve focus with binoviewers.

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BigMak. Do you know how to remove the empty part of the ota from the focuser block? As i am sure i read on a blog that it can be done so that you can achieve focus with binoviewers.

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Not totally sure what you are referring to. I have a long and a short tube for my 60, the short one allows bino viewers to be used but I haven't tried this yet

Stu

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My FS60, the rack and pinion is house in a lime green moulding which ill refer "focuser block". The. Theres the lens cell and dew cover than unscrews leaving an empty OTA section attached to the focuser block.

So i ask those who have an fs60, can the empty tube be removed from the focuser block, it does not seem to unscrew. Ived tried with a lot of force. The PDF manual i read says nothing about how it separates.

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My FS60, the rack and pinion is house in a lime green moulding which ill refer "focuser block". The. Theres the lens cell and dew cover than unscrews leaving an empty OTA section attached to the focuser block.

So i ask those who have an fs60, can the empty tube be removed from the focuser block, it does not seem to unscrew. Ived tried with a lot of force. The PDF manual i read says nothing about how it separates.

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Hi,

That's clearer, and the answer is yes, the tube should unscrew off the focuser block. I do not recall there being anything tricky about it, or even a locking screw but it definitely separates on mine. As said, mine came with two tubes so you can change it over completely.

I do however recall reading that you can convert one version into the other, but not the other way round. Not entirely sure what that means in reality. How long is your tube 145 or 110mm?

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The empty part of the ota is 125mm. The empty part plus lens cell/ dew cover section is 210mm. Thats odd... Mine does not match your dimensions. Mines the blue CB edition. Got it from astro buy sell last week, impulse by because i wanted to own a "premium brand" at an affordable/ish price.

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It looks like the anniversary model is slightly different then. My two tubes are 105 and 145mm respectively, so it looks like your tube a designed to split the difference. May still be ok with binoviewers.....

The Objective Upgrade weighs in at 940g ish including caps. Just weighed my FS-60C including tube rings and 2" diagonal plus FeatherTouch and it is bang on 2kg. Pretty good. Means I've can take 2 scopes away for under 3kg!

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Thats amazing. I have a horrid feeling the OG upgrade may not work on my anniversary model due ti the different tube lenght. Do you mean that you FS60 comes with two tubes and you can choose which one you wish to use?

Thanks for the weights and time. I am sure a lots of people will find your facts very useful. I am very grateful. [emoji4]

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Edited by Pingster
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I will post up some pictures in a while, maybe tomorrow.

Please don't worry about your scope, I am pretty sure that the scope you bought was sold by the same chap I bought my Objective Upgrade from, which would imply they work ok. Normally with Taks it's just a case of getting some extension tubes if needed anyway as they are more aimed at imaging.

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Awesome xD you are a gent. Maybe if i twist harder it will come off as "fitted" it looks like yours, it appears it could well be wielded on . But i can clearly see the thread and it looks very fine pitched.

Btw i stumbled into a thread where you used a TS flattener on your TV scope with 2in eyepieces. Are you still using that combo?

And cant wait till you get to do the three scope faceoff in your original post.

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Perhaps it is cold welded in some way? You should check into this more but applying gentle heat (hair dryer?) to the tube may help....

When I use my widefield eyepieces such as the Ethos then yes I do use the TS flattener. It does allow centre and edge focusing simultaneously and improves the view.

Unfortunately I think field curvature is just a fact of life in short focal length refractors, 100 degree afov eyepieces just draw even more attention to it.

Stu

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