A Newbie's Impression of the Takahashi FSQ106 EDX4-Update 2

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A Newbie's Impression of the Takahashi FSQ106 EDX4-Update 2

Post by chancy_sg » Tue Jan 17, 2017 10:20 pm

Having sold the FSQ85, a replacement was needed. After some asking around on potential 4inch scopes, I settled on the bigger version of the FSQ series. The 106 in its latest iteration - the EDX4 - comes without the captain's wheel and replaced this with a massive 4inch focuser and short draw-tube to maximise stability and minimise flex. On a trial run with a 50MP Canon 5DS, the stars are round all the way in the 4 corners - truly flatfield.

Tak now offers the 106 with double rings and plates, presumably for the Tak guider set with 35mm x2 spacing as standard- note this is not a hinged ring, it is solidly screwed on both halves. The original clamshell will not work with this Tak guider as it has a tripod screw on top. Starbase now sells a special version of the clamshell with the 35mm spacing, but you would need to personally go to the shop at Akihabara to pick it up...better to call and make sure. I use a basic Kowa 100mm CS lens with a 1.25inch guidecam on a K-astec mini saddle, so it works similarly to the Tak set with the 35mm spacing.

Setup aside, the image quality of the 106 is really good. on a 36x24mm, there is no noticeable light falloff...well, it covers an 88mm image circle with 60% falloff, but still it is nice to know it delivers as promised. At F5, the image is well defined, resolution is excellent, and focusing a breeze, especially on a DSLR with liveview. The focuser is smooth yet tight, with no backlash at all. I have yet to try the F3 reducer and will update here once I have enough experience with it. Total setup weight is about 10kg, and it balances very nicely due to the short and fat OTA design.

As an astrograph then, it clearly is a classic in the making, if not already. Only one drawback is the difficulty of adding the extender 1.6 to make it an F8 visual scope: there is no system chart for the EDX4 as of now to show how it is done, and without resorting to swapping out screws or replacing the entire imaging train with visual adapters a la the ED version.

No,it is not a cheap OTA, and many more generically made ones come very close, or possibly exceed it in optical standard, but somehow the whole package feels very robust and reassuring that is a well engineered piece of imaging equipment. If you are thinking of one, don't think too much longer; you won't regret getting it! I seldom see an FSQ106 ED version listed for sale ... :P

Some details:
Focal length 530mm at F5 and 318mm at F3 (848mm at F8 with extender)
Image circle - 88mm/44mm - flatfield
Weight about 6.5kg
125mm diameter tube
4inch focuser with short travel
4 element Petzval design

PS: Now to pair it with a suitable imaging camera... [smilie=hot.gif]

UPDATE: Recently, Takahashi released the system chart for adding the extender 1.6Q to attain the 848m focal length at F8. I managed to borrow an extender from the beginner and tried it out this last Mersing trip. The only major drawback is there is no camera angle adjuster in the image train and so any compositional adjustment is by releasing the screws. Took some images with the ASI1600MM cooled and the star-field seems flat, so no issues there. So this makes the FSQ106 a truly 3 focal length astrograph.

UPDATE 2: This July Mersing trip finally gave me an opportunity to use the F3 reducer with a unmodded fullframe 36x24mm DSLR. The reducer screws inside of the focuser body to achieve an F3 equivalent wide FOV of 318mm ie 6.5x4.3 deg with the FF sensor. It is the FOV that is the key, not so much the f ratio. With the 106mm aperture, wide vistas are captured with the image circle of 44mm, and stars are pinpoint with no CA to the extreme corners. Contrast is excellent and vignetting is minimal, at least for 300sec exposures. All in all, a great reducer to complete the versatile tri-focal astrograph setup from medium to wide field.
Last edited by chancy_sg on Tue Jul 25, 2017 3:55 pm, edited 3 times in total.
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Re: A Newbie's Impression of the Takahashi FSQ106 EDX4

Post by Airconvent » Wed Jan 18, 2017 1:59 pm

Very nice (and $$$) scope indeed. Taks were very popular in the early days of Singastro. One member even used a Tak 102 as a finder for his 10" LX200. :)
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Re: A Newbie's Impression of the Takahashi FSQ106 EDX4-Updat

Post by chancy_sg » Tue Jul 25, 2017 4:01 pm

UPDATE 2 included.
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Re: A Newbie's Impression of the Takahashi FSQ106 EDX4-Update 2

Post by tommy » Thu Jul 04, 2019 12:00 pm

Congrats, fsq106 is a very beautiful scope, but here are some issues you need to take care of, It’s not easy to get this scope work, especially when installing a full frame camera with it , the imaging plane will be very sensitive, you may need a camera tilt unit to help adjust, and you may replace the stock focuser to some very expensive one like FLI or nite crawler which will cost at least 3000SD, the reason is quite simple, TAK’s stock focuser sucks, it just can’t handle any weight over 2kg. And I don’t how dare it declare the focuser is especially designed for heavy image train
Btw, I personally don’t recommend to use full frame camera with fsq106 , even it’s official said to has a Monster image circle of 88mm, bcz I can only see a few people can get sharp and round stars ar 4 corners by using full frame camera
Hope you like your fsq106 , it’s not good enough but is the best among 4inch telescopes

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