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Need Help With TAK Purchase...

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#1 pb12

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Posted 20 August 2018 - 12:12 PM

Hello --

 

I currently own (and love) a Takahashi FC-76DS that I use as my travel scope, and keep setup on a DM-4 and tripod in the summer months (thats when you can actually see the sky here in Oregon...except for the smoke...anyway), I also own a TEC-160FL that is obviously not a grab and go type of set-up. Honestly, its huge, and a bit of a task to set up...you all know how it goes.

 

So, I am in the process of buying another scope, and I am desperately trying to decide between the FC-100DL or TSA-120. What caught my eye recently was this review on a Vixen scope;

 

http://scopeviews.co.uk/VixenFL80S.htm

 

In particular, his comments about the red spectrum being so poorly corrected for. I am curious if anyone can comment on how the 100DL might compare with the TSA in this regard. 

 

The other question I have is, while the TSA is a good 50%+ more money than the Dl, but will I really notice any difference in the DL compared with my 76DS, on planets for example?

 

Lastly, this is strictly for visual use.

 

Thoughts?

 

Michael



#2 balu01

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Posted 20 August 2018 - 12:59 PM

I do have the DL however I cannot compare it with the TSA as I have not tried one YET.
If you are after visual the DL is hard to beat, in my opinion when you consider - cool down, weight etc compared to a triplet.
Superb star test, no false color on planets. Takes extreme mags, will run circles over the 76DS on planets.

You really can't go wrong with either one , if you are also imaging, the triplet might serve you a tad better, I do image with the DL also, not much objectionable regardless of being a doublet.

Edited by balu01, 20 August 2018 - 12:59 PM.

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#3 jay.i

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Posted 20 August 2018 - 01:15 PM

120mm gathers 2.5x as much light as 76mm. You will see quite a difference. I can see a difference between 105mm and 76mm which is 1.91x the light gathering. You should definitely be able to see an improvement with 100mm over 76mm (1.73x) but it might not smack you in the face like going up to 120mm would. You need not worry about red correction in either of those scopes, both being at the top of the heap for their aperture class. If you can afford it, I would go for the TSA-120 for sure. It will take a little longer to cool down than the FC-100DL, but not by much, and you'll get a lot more bang out of it.


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#4 RAKing

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Posted 20 August 2018 - 01:17 PM

I have a couple of thoughts - how often do you use the TEC 160?  It is obviously the best scope in the bunch, but if you rarely take it out....

 

Both the 100 and 120 will show a lot more than the 76 and the 120 will show more than the 100.  The doublet 100 would be a better grab and go rig than the TSA-120 triplet.  The 100 could replace your 76 on the grab and go DM-4 if that is important to you.  The 100 will show quite a bit more than the 76 in day to day use and the 76 could stay as your travel scope.

 

But if you are looking for something bigger that you might use more often than the TEC 160, then downsizing to the 120 makes the most sense.  I owned a TSA-120 while I was recovering from surgery in 2012 and it was a nice substitute for my TEC 140.  I considered it to be more than a big 4-inch scope - it acted more like a "smallish" 5-incher.  Other than the slightly dimmer view, there is no difference in quality.

 

No matter which one you choose, you will end up with three top quality scopes. cool.gif 

 

Cheers,

 

Ron



#5 dweller25

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Posted 20 August 2018 - 02:02 PM

I have a TSA102 and an FS128 - The FS128 shows a lot more planetary detail visually.

 

If I had to choose between the FC100 or the TSA120 it would be the latter (with the Feathertouch focuser) as it is not too heavy and will show more detail. Both will out perform the FC76.

 

Nice choice to have smile.gif


Edited by dweller25, 20 August 2018 - 02:04 PM.

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#6 Erik Bakker

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Posted 20 August 2018 - 02:30 PM

Hello --

 

[....]

 

What caught my eye recently was this review on a Vixen scope;

 

http://scopeviews.co.uk/VixenFL80S.htm

 

In particular, his comments about the red spectrum being so poorly corrected for. I am curious if anyone can comment on how the 100DL might compare with the TSA in this regard. 

 

[....]

 

Lastly, this is strictly for visual use.

 

Thoughts?

 

Michael

Michael, you misinterpreted the graph. It's about the red correction for an f/6 scope, NOT the Vixen fluorite.

 

In the text Roger Vine explains why some scopes do poor in the red end of the spectrum. NOT the FL80 S however, that's why he likes it so much. Other quality f/8 wish fluorite doublets like the Tak FS/FS also do well in the red. Not ED doublets as he explains. Others have also found the fluorites to be well corrected in red. Both the FC-100 DL and TSA120 are even better corrected. Much better even.

Here is a similar graph across the spectrum of an 102mm f/8 Tak fluorite doublet.

 

A quote from the same review you mentioned sums up Roger Vine's opinion nicely:

 

"The FL80 is, in my view, another example of where fluorite matters. In this case the magic mineral provides a level of correction for chromatic aberration that I have never seen in an ED doublet of similar spec’ (though I’m willing to stand corrected if one turns up). Make no mistake about it, the difference is quite subtle, but turn up the magnification on a double star or planet (especially Mars) and the FL80 performs noticeably better than a fast ED doublet, even an excellent one like the TV-76 or TV-85."

 

Hope this clarifies the matter.


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#7 dr.who

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Posted 20 August 2018 - 02:57 PM

The extra 20mm will be quite noticeable. As an alternative sell the 160, buy the TSA and FC, get a Mewlon 210, get a Baader 1.25x GPC, Baader prism diagonal, Tele Vue binoviewer, Tele Vue Nagler 16mm and 11mm pair as well as a 24mm panoptics pair, mount the TSA and Mewlon on a Skywatcher AZ-EQ6 or if you are into star hopping the Losmandy AZ8 and get the best of both worlds. My Mewlon 210 changed my opinion of Jupiter and moved it from my least favorite planet to my third behind Saturn and Uranus.

In the binoviewers on a good seeing night it is breathtaking. As are the other planets, small DSO, small planetary nebulae, globulars, and small galaxies. The TSA rides next to it and goes for open clusters, large DSO/Nebulae, and doubles. Like peanut butter and chocolate, a winning combination. And the combination will be substantially easier to mount and move than the 160. The FC can be your G&G.

Means you will be much likelier to use them thus making them the best scopes for you. Per th3 rule of thumb on the best scope.

#8 NickWDavis

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Posted 20 August 2018 - 02:57 PM

When I read the title of your post I thought you were going to ask for financial help.

 

That is the kind of help I need with a Tak purchase.


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#9 pb12

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Posted 20 August 2018 - 03:09 PM

Michael, you misinterpreted the graph. It's about the red correction for an f/6 scope, NOT the Vixen fluorite.

 

In the text Roger Vine explains why some scopes do poor in the red end of the spectrum. NOT the FL80 S however, that's why he likes it so much. Other quality f/8 wish fluorite doublets like the Tak FS/FS also do well in the red. Not ED doublets as he explains. Others have also found the fluorites to be well corrected in red. The TSA and DL do even better, but are very different scopes.

Here is a similar graph across the spectrum of a fluorite doublet.

 

A quote from the same review you mentioned sums up Roger Vine's opinion nicely:

 

"The FL80 is, in my view, another example of where fluorite matters. In this case the magic mineral provides a level of correction for chromatic aberration that I have never seen in an ED doublet of similar spec’ (though I’m willing to stand corrected if one turns up). Make no mistake about it, the difference is quite subtle, but turn up the magnification on a double star or planet (especially Mars) and the FL80 performs noticeably better than a fast ED doublet, even an excellent one like the TV-76 or TV-85."

 

Hope this clarifies the matter.

Erik -

 

Thanks for chiming in here. No, I fully understood what he was saying. The reason it caught my eye is because he was, as you point out, talking about how well the Vixen does in this regard, BUT how poorly other, well, I'll just quote:

 

"The following graph, of optical quality, in the guise of Strehl ratio, at different wavelengths for a fast APO, explains why such scopes can be poor on Mars. To put those Strehl figures into context, 0.95 is excellent, 0.80 barely acceptable. So, in the red (and even yellow to some extent) your expensive, beautifully figured APO lens turns into a piece of bottle glass!"

 

Now, HERE is where I certainly may have misinterpreted ...Are both of these not "Fast APO's"?

 

Then, there is this graph from telescopes.net for the TSA:

 

https://telescopes.n...lescope-4e3.jpg

 

Looks to me like the red spectrum is the worst of the bunch...but maybe it is all relative, and its still great compared with other scopes?

 

In his review of the FC-100DL:

 

http://www.scopeview...k/TakFC100s.htm

 

he shows another graph in comparison of the FOA-60...looks as though the DL and TSA are pretty similar in the red spectrum...or am I reading that incorrectly? And again, for visual...does it matter?

 

 

Thanks!

Michael


Edited by pb12, 20 August 2018 - 03:13 PM.


#10 pb12

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Posted 20 August 2018 - 03:33 PM

I have a couple of thoughts - how often do you use the TEC 160?  It is obviously the best scope in the bunch, but if you rarely take it out....

 

Both the 100 and 120 will show a lot more than the 76 and the 120 will show more than the 100.  The doublet 100 would be a better grab and go rig than the TSA-120 triplet.  The 100 could replace your 76 on the grab and go DM-4 if that is important to you.  The 100 will show quite a bit more than the 76 in day to day use and the 76 could stay as your travel scope.

 

But if you are looking for something bigger that you might use more often than the TEC 160, then downsizing to the 120 makes the most sense.  I owned a TSA-120 while I was recovering from surgery in 2012 and it was a nice substitute for my TEC 140.  I considered it to be more than a big 4-inch scope - it acted more like a "smallish" 5-incher.  Other than the slightly dimmer view, there is no difference in quality.

 

No matter which one you choose, you will end up with three top quality scopes. cool.gif

 

Cheers,

 

Ron

How much do I use the 160....thats the issue right there, not much. But(!) I love the thing...Its a ton of money tied up in a scope that gets out a 2-4 times a year...My hope of course is to one day have it permanently mounted. In the mean time, its really a "special occasions" scope. 

 

Your thinking on keeping the 76 as my travel scope only, is spot on. It fits in a cary-on case perfectly.

 

The 76 on a Berlbach Planet is one trip to the back yard, not sure a TSA would still be one trip.


Edited by pb12, 20 August 2018 - 03:39 PM.

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#11 Erik Bakker

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Posted 20 August 2018 - 04:05 PM

The FC-100 DL and TSA120 are both wonderful, yet very different scopes. If your scope endures larger temperature swings, the FC-100 DL will deliver fantastic images much sooner. Like up to an hour earlier than the TSA120.If temperature swings are small, or if you have the time to let the TSA120 settle, it is an absolutely stunning scope too, with more aperture. Albeit front heavy because of the triplet objective.



#12 jay.i

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Posted 20 August 2018 - 04:07 PM

The FC-100 DL and TSA120 are both wonderful, yet very different scopes. If your scope endures larger temperature swings, the FC-100 DL will deliver fantastic images much sooner. Like up to an hour earlier than the TSA120.If temperature swings are small, or if you have the time to let the TSA120 settle, it is an absolutely stunning scope too, with more aperture. Albeit front heavy because of the triplet objective.

The TSA-120 doesn't really need >1hr to cool down, does it? I have read that it cools down faster than expected for a triplet of its size. I would expect maybe an hour if it's a >=25F temp delta, but not 15 or under... 



#13 CounterWeight

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Posted 20 August 2018 - 04:39 PM

Greetings from a fellow PDX'er.  A while back you could have come over here (I'm over in the Ladds / Hawthorne area) and sky permitting seen for yourself...  I love the Tak line of scopes. And possibly compared with one of my FS-128's !  at least that is what I was doing.

 

I owned the 'DF' variant and was a s sweet as I hoped, really top quality and color free.  The TSA is an amazing little scope for several reasons.  Small and lightweight for a triplet (especially a Tak, wrt the TOA 130), easy to mount!  I was using an Orion Skyview pro for both - no issues and I like a solid mounted view.  Comparing the TSA 120 to the FS 128 was more labor than I like.  I really between the FS and TSA could never find anything remotely objectionable or less than outstanding, planetary views 'comparable', globulars 'comparable', doubles 'comparable'.

 

Both the newer 100 mm line and the TSA have a cooler view to my eye than the older 'FS' variants, using the ep's in my sigline.

 

IMO in our typical and even better than typical skies you will run out of sky conditions or exit pupil if pushing the magnification up to the high end.

 

There is to me a noticeable but NOT big difference in going from 100 to 120 on planets, globs, doubles.  To me these are small aperture and good to temper expectations based on that.  Wonderful scopes all, and if I was better off financially I'd still have them all.


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#14 Kunama

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Posted 20 August 2018 - 05:09 PM

I think the TSA fits better between your current scope lineup. Having said that, the FC100DL is a beautiful visual instrument, better corrected than the shorter DC/DF, also half the weight of the TSA120.

The DL cools in half of the time of the TSA120. TSA dew shield retracts whereas the DL does not.  As visual instruments you wouldn't be unhappy with either.

The TSA comes with a larger 2.7" focuser vs. the 2.5" on the FC100DF and DL.


Edited by Kunama, 20 August 2018 - 06:05 PM.


#15 StarDust1

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Posted 20 August 2018 - 07:23 PM

Michael,

 

I have used both, FC-100DL and TSA-120. These scopes are build with a different philosophy by Takahashi. From these two the FC-100DL is a grab&go compared to the TSA-120. The TSA-120 needs a beefier mount then the FC-100DL. The FC-100DL has a tube diameter of 95mm compared to the 125mm of TSA120. The FC-100DL fits inside the belly of the TSA120. The FC-100DL is thin, long and a low weight, it cools really fast. Both give color free views to my eyes. The visual difference on the planets between the FC-100DL and TSA-120 is small IMHO, but on deepsky like globular the TSA-120 is the way to go. That extra 20mm makes big difference in my book on deepsky, but not so much on the planets. 

 

If I had to choose between these two scopes, I would ask my self the following question:

- The average duration of my observation sessions? 1hour or longer?

- Would I be able to leave the scope outside before observing for the cooldown?

- Would I mind the extra weight of the TSA-120 over the FC-100DL

 

If I would use the scope for short sessions, like an hour or two each session then I would go with the FC-100DL.

If I would use the scope on average for longer sessions, for example more than two hours, and I wouldn't mind the extra weight, then I would go for the TSA-120.

 

The best current available portable 4" Tak is the FC-100DF by a long shot. And the most gorgeous 4" Tak is the FC-100DC.

 

TSA120 and FC100DC.jpg

Edited by StarDust1, 20 August 2018 - 07:29 PM.

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#16 Howard Gao

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Posted 20 August 2018 - 08:08 PM

Just FYI FC-100DL has been discontinued and there a few ones in stock.



#17 jag32

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Posted 20 August 2018 - 08:11 PM

I don't think a FC-100DL vs. TSA-120 comparison is very good, rather the TSA-120 is more comparative to the TOA-130.  The FC-100DL and TSA-120 are two different scopes in two different classes.  The TSA-120 is, hands down, better than the FC-100DL in every way except for size/weight.  And the size/weight of the TSA-120 is very light and your DM-4 mount is absolutely perfect for a TSA-120.  You don't need to worry about size/weight with the TSA-120, it is compact enough with the dew shield retracted and and only weighs 14 pounds, which is nothing and can be lifted with a finger.  Personally, I think the TSA-120 is overpriced at roughly $4,500 and then you'll need another ~$500 in accessories to include the tube ring, finder scope, finder scope bracket, etc. bringing the total cost to a $5,000 scope.  I think you would be better served buying an APM 140 with FPL-53 glass, which is only about 4 pounds heavier than a TSA-120, half the price, equivalent optical quality, and an additional 20mm of aperture.  I'm a Takahashi guy through and through, I still have two, but the APM 140 is a hell of a telescope.

 

I sold the TSA-120 because I got aperture fever and bought a 16" Newtonian from Orion Optics UK with 1/10 optics.  Wish I still had it, but if I ever choose to replace it, it will be with a used TOA-130 at roughly the same cost as a new TSA-120.


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#18 jay.i

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Posted 20 August 2018 - 08:14 PM

I don't think a FC-100DL vs. TSA-120 comparison is very good, rather the TSA-120 is more comparative to the TOA-130.  The FC-100DL and TSA-120 are two different scopes in two different classes.  The TSA-120 is, hands down, better than the FC-100DL in every way except for size/weight.  And the size/weight of the TSA-120 is very light and your DM-4 mount is absolutely perfect for a TSA-120.  You don't need to worry about size/weight with the TSA-120, it is compact enough with the dew shield retracted and and only weighs 14 pounds, which is nothing and can be lifted with a finger.  Personally, I think the TSA-120 is overpriced at roughly $4,500 and then you'll need another ~$500 in accessories to include the tube ring, finder scope, finder scope bracket, etc. bringing the total cost to a $5,000 scope.  I think you would be better served buying an APM 140 with FPL-53 glass, which is only about 4 pounds heavier than a TSA-120, half the price, equivalent optical quality, and an additional 20mm of aperture.  I'm a Takahashi guy through and through, I still have two, but the APM 140 is a hell of a telescope.

 

I sold the TSA-120 because I got aperture fever and bought a 16" Newtonian from Orion Optics UK with 1/10 optics.  Wish I still had it, but if I ever choose to replace it, it will be with a used TOA-130 at roughly the same cost as a new TSA-120.

A TSA-120 would be marginal on a DM4 depending on the tripod. Check this thread here for mounting suggestions: https://www.cloudyni...-tsa-120-setup/



#19 StarDust1

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Posted 20 August 2018 - 08:28 PM

You don't need to worry about size/weight with the TSA-120, it is compact enough with the dew shield retracted and and only weighs 14 pounds, which is nothing and can be lifted with a finger. 

I needed both hands to lift the TSA-120 ota comfortably, as with the FC-100DL ota one hand was enough. I need to go to gym more often mad.gif



#20 jag32

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Posted 20 August 2018 - 08:57 PM

A TSA-120 would be marginal on a DM4 depending on the tripod. Check this thread here for mounting suggestions: https://www.cloudyni...-tsa-120-setup/

 

I had my TSA-120 on a DM4 and it was rock solid, in fact I've had nearly 30 pound OTAs double in weight on my DM4 and it was solid.  As long as the setup is supported by a robust tripod there won't be any issues with the SAME and TSA-120 combo.



#21 jay.i

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Posted 20 August 2018 - 09:02 PM

I had my TSA-120 on a DM4 and it was rock solid, in fact I've had nearly 30 pound OTAs double in weight on my DM4 and it was solid.  As long as the setup is supported by a robust tripod there won't be any issues with the SAME and TSA-120 combo.

Which tripod did you have DM4 on, when you ran the TSA-120 on it? Your Planet? I am considering a UNI 24 but the Planet isn't much heavier (like 25lbs vs 20lbs) and it would be even sturdier.



#22 jag32

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Posted 20 August 2018 - 09:08 PM

Which tripod did you have DM4 on, when you ran the TSA-120 on it? Your Planet? I am considering a UNI 24 but the Planet isn't much heavier (like 25lbs vs 20lbs) and it would be even sturdier.

My report 723. The uni 24 will be more than fine. You don't need a planet unless you have a much heavier TOA130 or TOA150.



#23 jay.i

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Posted 20 August 2018 - 09:19 PM

My report 723. The uni 24 will be more than fine. You don't need a planet unless you have a much heavier TOA130 or TOA150.

The thing is I might get an even larger scope to use with a heavier duty mount than what I currently have. The Planet would be future-proof in that sense. I like the ease of use carrying my Report out onto the balcony with even the TMB105 already mounted on it, but with either the UNI or Planet it would be much more of a grunt and go setup. Might as well spend a little more if I'm gonna deal with the weight and get the sturdier tripod. Then I can sell the Report.



#24 CounterWeight

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Posted 21 August 2018 - 12:27 AM

I had a BB Planet tripod for many years, very solid!  I think largest mount I used was the A-P mach1 / , pretty certain you could go larger.  I only had the 'single leg clamp' version, there is a double clamp as well.



#25 CounterWeight

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Posted 21 August 2018 - 12:37 AM

WRT the TOA-130 ... again I found it difficult to see improvement compared to the FS-128 doublet in typical and better PNW seeing, I usually only recommend if imaging is in the cards. In the climate here if can be left out to acclimate the TOA no problem.  If setting up and tearing down the FS-128 or the TSA-120 a better choice IMO in the ~5" realm.  The FS-102 and FC100 DF again the only difference to my eye was the color tone, the FS being warmer.  But this is in ways hair splitting.  Looking at the double cluster or Alberio for example, both show star colors and are great 'eyepiece testing' platforms.

 

There are no 'bad choices' here in Tak lineups, all I have owned have been fantastic visual tools within what they can reasonably be expected to do.


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