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TAK Doublet or Stellarvue Triplet?

refractor astrophotography
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#26 25585

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Posted 13 September 2020 - 06:55 AM

When you buy Tak, you are buying into a system, as for photography. There is a manufacturer-customer mindset. Only Baader and Tele Vue have big astro accessory systems in the west AFAIK.

 

My only Tak accessories are (dedicated) extenders & a prism diagonal. All work excellently with my Tak fracs, as well they should.


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#27 Scott99

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Posted 13 September 2020 - 10:51 AM

I've used an FC100-DL and the color correction appears to be similar in the DZ.  Optically these are fairly unique and work just as well as a triplet, so I would base your decision on something other than the doublet/triplet issue.  I would decide based on the other aspects of the scope.


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#28 StarAlert

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Posted 13 September 2020 - 08:51 PM

I have the DL and the DZ. An astronomy buddy brought his DF over one night last week (before all the fires) to compare it to the DZ. We could see no difference between the two. I also compared the DL to my TSA 120 on several occasions (before I sold the TSA recently, and replaced it with a Mewlon). The DL doublet is nearly as good as the TSA triplet. That's to say that both scopes are top notch. You don't need a triplet when you go with a 4" Tak.

Just my two cents. 


Edited by StarAlert, 14 September 2020 - 09:05 AM.

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#29 barbie

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Posted 13 September 2020 - 09:49 PM

Over the years, I've had both Tak and Stellarvue( currently have Tak) and both brands are extremely excellent!!  You really can't go wrong with either brand.


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#30 sunnyday

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Posted 13 September 2020 - 10:07 PM

I have no regrets about my purchase, on the contrary I am very proud of it.
you will be a new victim of the disease called Takitis.


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#31 nicknacknock

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Posted 14 September 2020 - 05:10 AM

For those of you imaging with the Tak, do you find not having a dual-speed focuser as an obstacle, or no big deal?

You can install the MEF-3 dual speed focuser from Takahashi. I always prefer the comfort and absolute control over focusing offered by a dual speed focuser...


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#32 Hesiod

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Posted 14 September 2020 - 05:32 AM

I use my FC100 for imaging and the lack of dual speed focuser has never been an issue, as the focuser is smooth and accurate enough for the task.
I have however been bothered by the stiffness of the CAA, the wretched device which should allow the camera to rotate.

#33 25585

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Posted 14 September 2020 - 06:00 AM

I have the DL and the DZ. An astronomy buddy brought his DF over one night last week (before all the fires) to compare it to the DZ. We could see no difference between the two. I also compared the DL to my TSA 120 on several occasions (before I sold it recently, and replaced it with a Mewlon). The DL doublet is nearly as good as the TSA triplet. That's to say that both of them were top notch. You don't need a triplet when you go with a 4" Tak.

Just my two cents. 

But the TSA-120 is a 120 - nearer 5" than 4", and faster by f1.5. I have compared my DL and TSA-120, and the latter is perfect.

 

A TSA-102 v FC100DZ v FC100DC/F would be fairer. 



#34 Faber

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Posted 14 September 2020 - 06:04 AM

Dear 25585,
Sorry but by saying the tsa 120 is perfect you mean itโ€™s better corrected than the fc 100dl or more useful( sure the diameter is bigger). Thank and best regards

#35 RAKing

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Posted 15 September 2020 - 08:44 AM

Just to add: A doublet is perfectly fine for AP. The color correction on the DZ is simply sublime and for AP, paired with the right Takahashi reducer, it will produce pure apochromatic images.

 

If you check into the technical books on scope design, I think you will be satisfied that doublet refractors designed with CaF2 (fluorite) compare quite favorably with triplets using other ED types of glass - especially if you are working at longer focal lengths.  So I have no doubts that my Tak fluorite doublets can hold their own with any other scope in their aperture class.

 

 

For those of you imaging with the Tak, do you find not having a dual-speed focuser as an obstacle, or no big deal?

 

It's no big deal, especially if visual observing is your first love.  If the imaging bug bites bad enough, it's easy enough to add the Tak MEF-3 or the FeatherTouch MPA to your focuser at a later time.  The FT is my favorite, but either of these will add a nice touch to a really nice scope, IMHO.

 

This is my 26-year old FC-100 with the FT MPA and it still works great!

 

Cheers,

 

Ron

 

Tak FC-100 050120.JPG


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#36 PowerM3

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Posted 15 September 2020 - 09:10 AM

Interested in the recommendations given here. My question is: is a DZ/DL better color corrected then a FS scope(I used to own the FS-128)?



#37 aa6ww

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Posted 15 September 2020 - 09:38 AM

Unless the seeing and transparency is perfect in both cases, which happens sometimes less then once a year, I doubt visually anyone can see any differences between any Takahashi's of any vintage of similar apertures. Especially if your eyes are older.

They are all excellent. 

 

...Ralph

 

 

 

I have the DL and the DZ. An astronomy buddy brought his DF over one night last week (before all the fires) to compare it to the DZ. We could see no difference between the two. I also compared the DL to my TSA 120 on several occasions (before I sold the TSA recently, and replaced it with a Mewlon). The DL doublet is nearly as good as the TSA triplet. That's to say that both scopes are top notch. You don't need a triplet when you go with a 4" Tak.

Just my two cents. 


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#38 RAKing

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Posted 15 September 2020 - 10:11 AM

Interested in the recommendations given here. My question is: is a DZ/DL better color corrected then a FS scope(I used to own the FS-128)?

 

There is no visual difference between my Tak FC (Steinheil design) and my Tak FS (Fraunhofer design) aside from brightness. cool.gif   Both are f/8 and the only difference aside from aperture is the position of the fluorite element.

 

What I like the most about these two scopes is their weight.  Both of these scopes replaced similar-sized triplets and both of them are much lighter and easier for me to handle than their predecessors. 

 

Having said that, Tak has reduced the tube diameter of the new FC series scopes and they are even lighter than my older FC-100.  I think any of the new FC-100D series (DC, DF, DL, or DZ) would be a great choice for a new 4-inch refractor.  I owned an FC-100DC before I found this older Tak and it was a superb scope.

 

Cheers,

 

Ron


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#39 Lola Bruce

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Posted 15 September 2020 - 10:31 AM

Tak


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#40 PowerM3

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Posted 15 September 2020 - 10:45 AM

There is no visual difference between my Tak FC (Steinheil design) and my Tak FS (Fraunhofer design) aside from brightness. cool.gif   Both are f/8 and the only difference aside from aperture is the position of the fluorite element.

 

What I like the most about these two scopes is their weight.  Both of these scopes replaced similar-sized triplets and both of them are much lighter and easier for me to handle than their predecessors. 

 

Having said that, Tak has reduced the tube diameter of the new FC series scopes and they are even lighter than my older FC-100.  I think any of the new FC-100D series (DC, DF, DL, or DZ) would be a great choice for a new 4-inch refractor.  I owned an FC-100DC before I found this older Tak and it was a superb scope.

 

Cheers,

 

Ron

Ok, thanks for the input! Visually I agree that a Tak doublet is a good choice. I have not used the Stellarvue scope in question so I cannot comment on that. I can say that even visually the Tak doublets do show a decent amount of secondery color at high power when side by side with a premium triplet(I have compared side by side with a 102/650 LOMO). My eyes are very sensitive to blue though so maybe most would not see much of a difference visually...

 

Not trying to start a Tak holly war, just a data point. I still own an FSQ-106 and think that Taks are good scopes.


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#41 bulletdodger

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Posted 15 September 2020 - 11:02 AM

Buy Used!!

Lots of good opportunities to get a Telescope that fills your needs right here on CN. Please don't let that money burn a hole in your pocket. I have a TV-102 and an SV 102 APO lomo doublet that were half price and in great shape. The money saved from new could finance a field flattener and an Ethos. Fate rewards patience, (Usually! ๐Ÿ˜‰)
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#42 kmparsons

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Posted 15 September 2020 - 01:02 PM

I asked this same question several years ago and got a mixed response, with most favoring the TAK. I got the SV because I was able to do a trade-in and get a price reduction. I can only say that as a strictly visual observer, I have been most happy with my choice. I find the color correction to be excellent, and no  visual defects or aberrations. A longer focus would make planetary and lunar observations a bit more comfortable, but I have been told that the TV 3-6mm zoom eyepiece is excellent and allows for outstanding high magnification views for short to moderate focal lengths.


Edited by kmparsons, 15 September 2020 - 01:12 PM.

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#43 barbie

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Posted 15 September 2020 - 02:14 PM

I'm doing mainly visual so my long focal length fluorite doublet is all I really need or want. At f12.75, my Tak fc76DCU+ CQ extender is color free, has no field curvature or spherical aberration, and at 3 inches is extremely easy and portable to set up. I don't need anything more complicated or larger, I'm EXTREMELY pleased with the way this 76mm fluorite doublet presents the moon, planets and brighter multiple stars and DSO's which are what I primarily observe.


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#44 gnowellsct

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Posted 15 September 2020 - 02:36 PM

I would toss the hat of the CFF 105mm into this ring (f/7 or f/9).  It appears to be price competitive.   It is a triplet oiled objective.

 

Greg N


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#45 gnowellsct

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Posted 15 September 2020 - 08:26 PM

You have to get yourself into the mood to buy a refractor.  You may think it's an AP or a Vixen or whatever you have your heart set on.  But 9 times out of 10  something else comes first and it's terrific and you're in a mood to buy.

 

Greg N


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#46 Tyson M

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Posted 16 September 2020 - 12:42 AM

I use my FC100 for imaging and the lack of dual speed focuser has never been an issue, as the focuser is smooth and accurate enough for the task.
I have however been bothered by the stiffness of the CAA, the wretched device which should allow the camera to rotate.

My CAA on my TSA102S is like that too. Just awful and stiff to use.



#47 mikeDnight

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Posted 16 September 2020 - 08:51 AM

Interested in the recommendations given here. My question is: is a DZ/DL better color corrected then a FS scope(I used to own the FS-128)?

The FC100DZ technically has better colour correction than the FS and the DL, but I suspect the difference would only be detectable, with a critical eye as regards the FS and not at all with the DL.

 

2020-06-09 18.33.37.png

2020-09-16 15.09.07.png


Edited by mikeDnight, 16 September 2020 - 09:01 AM.


#48 StarAlert

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Posted 16 September 2020 - 08:57 AM

The FC100DZ technically has better colour correction than the FS and the DL, but I suspect the difference would only be detectable, with a critical eye as regards the FS and not at all with the DL.

 

attachicon.gif2020-06-09 18.33.37.png

How does one read this chart? 



#49 mikeDnight

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Posted 16 September 2020 - 09:11 AM

I'm not entirely certain as the Japanese is all Greek to me, but I imagine the 1.000 on the vertical graph could represent the diameter of the Airy disk. All colours are within that diameter on the DZ, and just one colour barely outside on the DL. I doubt this would be visible visually, and I haven't found a similar graph so far for the FS. Of course I could be wrong!


Edited by mikeDnight, 16 September 2020 - 09:14 AM.


#50 mikeDnight

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Posted 16 September 2020 - 09:28 AM

Here's a TSA / FS comparison.

 

2020-09-16 15.36.34.png


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