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Connecting CCD to Tak FSQ85

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#1 Greg S

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Posted 26 March 2014 - 06:52 PM

I just downsized to a new imaging rig which is a Tak EM11 with an FSQ85 ED running at the native focal ratio of F 5.3. I've got an Atik 460EX Color I want to hook up with all screw on connections.

The Atik needs 18mm of back focus. I have a whole bunch of Tak stuff lying around and none of the pieces let me connect other than as a 1.25" nosepiece which will have too much flex.

Are there any Tak experts out there that can tell me what pieces I need starting at the end of the camera angle adjuster and ending by threading into the Atik unit? It's got me baffled and these Tak adapters are expensive so I don't want to go by trial and error.

#2 andysea

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Posted 26 March 2014 - 08:03 PM

If the 460 has a t-thread you can have precise parts make a custom adapter that goes from the CA-35 to the T-thread of the camera.
I did that for my QSI. My adapter provides exactly 56mm back focus (accounting for the filter as well). That way I can use the CA-35/custom adapter combo with the FSQ106/reducer and TOA130/reducer. You may not be interested in the reducer but it's nice to have the option. Most takahashi configurations terminate with the CA-35 (TCA-1030) as the second to last piece. The back focus from the CA-35 is always 56mm so once you have a custom adapter that couples your CCD with the CA-35 and provides the required back focus your are set. There are a few exceptions like the FS-60.
There may be other ways to achieve this but this my experience. And yes those Tak adapters are very pricey!
You can find the system chart for the FSQ85 here
http://www.takahashi...ww.takahashi...

#3 Greg S

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Posted 27 March 2014 - 02:07 PM

Thanks Andy. I'm not sure it's any clearer to me. Maybe I'll just call Texas Nautical.

#4 andysea

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Posted 27 March 2014 - 02:21 PM

That is probably the best thing to do. I can assure you that once you figure it out the Takahashi system makes perfect sense especially if you have multiple scopes with different configurations, like reducers, extenders etc...

#5 yzhzhang

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Posted 27 March 2014 - 03:55 PM

If you're connecting FSQ85 without a reducer, then you probably don't have to worry about the back focus distance. I'd just have preciseparts make an adapter from M72(the end of the CAA) to T thread.

#6 andysea

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Posted 27 March 2014 - 05:25 PM

I actually think that if a custom adapter has to be made it may as well be one that provides the right back focus so that it can be used with reducers etc... in the future.

#7 Greg S

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Posted 27 March 2014 - 06:33 PM

That's what I'm going to do since I already have extenders and may use the reducer some day. Atik says this camera needs 13mm of back focus so that's how I will order the part.

$190.00 Ouch!

#8 andysea

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Posted 27 March 2014 - 07:13 PM

Yes I know. Pricey. However Preciseparts quality is excellent.

#9 Greg S

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Posted 27 March 2014 - 07:24 PM

Update. I need two parts as the reducer has a male thread and the effective focal length needs to be 59.2mm. One for the reducer; one for native.

#10 andysea

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Posted 27 March 2014 - 08:06 PM

Are you sure? I have the same reducer for my 106 and I have the following configuration.
Reducer + TCA-1020 (aka CA-35) + custom adapter for 56mm bf + QSI583wsg.
As far as I know the bacfocus is always 56mm from the CA-35.

There are three different CA-35's for different scopes and they always have the same male thread on the camera side and they all require 56mm back focus.






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