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Tak DL and Prism Diagonal

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#1 NickWDavis

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Posted 22 February 2020 - 09:36 PM

I’ve never used a prism diagonal but I am curious about the Tak 1.25 due to it’s low price. Is my DL long enough to benefit from a prism? I’m currently using either a Meade or William Optics 2” dielectric.

Thanks

#2 coopman

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Posted 22 February 2020 - 11:14 PM

From what I have read, f/8 and above works well with the Tak prism diagonal. I have one of the prisms in the mail currently and hope to check it out when I get some more clear skies.

Edited by coopman, 22 February 2020 - 11:15 PM.

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#3 rkelley8493

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Posted 23 February 2020 - 12:08 AM

I have the Baader T2 Zeiss Prism. It works very well in my Stellarvue f/7 Apo. I haven't used it with the Tak-100DF yet, but I plan on it soon. I tried the other night, but I'll need an extender to achieve focus. It requires a bit of back travel..


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#4 StarDust1

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Posted 23 February 2020 - 06:48 AM

Taks prism is excellent. It should work fine with your DL.
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#5 Hesiod

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Posted 23 February 2020 - 07:10 AM

I use a 1.25" prism with my DL and it works fine
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#6 mikeDnight

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Posted 23 February 2020 - 07:24 AM

I’ve never used a prism diagonal but I am curious about the Tak 1.25 due to it’s low price. Is my DL long enough to benefit from a prism? I’m currently using either a Meade or William Optics 2” dielectric.

Thanks

Definitely! The Tak prism is excellent and the DL will perform flawlessly with it.  I've used the DL on many occasions with both a Tak 1.25" prism and the Baader 1.25" prism, and its performance is simply perfection. The Tak prism works flawlessly in my FC100DC, so the DL will have no problem with it. Even when introducing a binoviewer into the mix the DC and DL are CA free.

The Tak prism is strong too, so you'll have no issues with it carrying any 1.25" eyepiece or binoviewer.

 

IMG_0653.JPG


Edited by mikeDnight, 23 February 2020 - 07:27 AM.

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#7 barbie

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Posted 23 February 2020 - 07:26 PM

I use a Tak prism with my older FC76 and it has allowed me to push that scope to 325X on the moon and tight doubles and images remain sharp!!


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#8 Bill Barlow

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Posted 24 February 2020 - 11:30 AM

I own two Tak 1.25” prism diagonals.  One is used in the 76DCU and the other was used in a 6” f/12 MAK.   Both perform exceptionally well,  very sharp stars and a lot of detail on planets.  Highly recommended.

 

Bill


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#9 j.gardavsky

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Posted 24 February 2020 - 02:18 PM

Today,

I have ordered the 1.25" Tak prism diagonal.

 

Reading the posts on CN becomes expensive,

JG


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#10 NickWDavis

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Posted 02 March 2020 - 08:29 PM

Thanks everyone. The prism arrived today but of course it is cloudy.
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#11 coopman

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Posted 02 March 2020 - 09:27 PM

I used my Tak prism diagonal for the 1st time a few nights ago.  Gosh, get used to turning the collar a LOT if your normal routine includes numerous changes of eyepieces.  I had to really rack the focuser out a long ways too.  Other than these nits, it seemed to perform well.   



#12 Kunama

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Posted 03 March 2020 - 04:50 PM

I used my Tak prism diagonal for the 1st time a few nights ago.  Gosh, get used to turning the collar a LOT if your normal routine includes numerous changes of eyepieces.  I had to really rack the focuser out a long ways too.  Other than these nits, it seemed to perform well.   

When I use eyepieces like the Panoptic or DeLite that have those stupid 'safety' grooves I don't insert them into the Tak prism more than the unadulterated section, then the clamp takes up with a 1/4 turn....

Tak LE can be inserted the full way....

 

But it there is a little trick you can use if all your eyepieces were designed for the clumsy ones among the fraternity....... unscrew the silver collar from the prism, flip the grey nylon compression band over and reinstall the clamp.....it will then clamp on the little bit that wasn't ruined down by an overzealous lathe operator... flowerred.gif


Edited by Kunama, 03 March 2020 - 04:51 PM.

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#13 coopman

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Posted 04 March 2020 - 10:17 PM

The safety groove is the big issue, I agree with that.  I found myself using any/all of my smooth barrelled eyepieces. 

Thanks for the tip Matt.  I will try that next time out.


Edited by coopman, 04 March 2020 - 10:23 PM.


#14 noisejammer

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Posted 05 March 2020 - 03:37 AM

Thanks for that idea, Matt. I'll give it a go with my Tak turret.

 

On prisms - my primary scopes are f/7 (APM 115/805) and f/7.3 (TOA 150). I only use my prisms and I have not observed spherochromatism. It may be there but it's drowned out by atmospheric dispersion.



#15 25585

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Posted 05 March 2020 - 04:57 AM

I have a DL which is fine with the Tak prism. But the T2 Zeiss from Baader would be more versatile. 



#16 NickWDavis

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Posted 05 March 2020 - 11:19 AM

I got to try out my new prism last night. Things didn’t go so great. Only one of my eyepieces was able to focus. For the others there wasn’t enough back focus. I tried using the extension that came with the scope but then there was too much.

#17 25585

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Posted 05 March 2020 - 12:11 PM

I got to try out my new prism last night. Things didn’t go so great. Only one of my eyepieces was able to focus. For the others there wasn’t enough back focus. I tried using the extension that came with the scope but then there was too much.

Which eyepieces did you have trouble with?


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#18 rkelley8493

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Posted 05 March 2020 - 02:39 PM

I used a generic 35mm extender with my T2 Zeiss prism to get it to focus. The extension tube that comes with the FC-100D looks like it's suited for a camera that requires a ton of back focus distance, or if you're doing straight thru viewing without a diagonal. It's a bit overkill for adding just a small distance to bring an accessory into focus.


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#19 25585

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Posted 05 March 2020 - 03:03 PM

I used a generic 35mm extender with my T2 Zeiss prism to get it to focus. The extension tube that comes with the FC-100D looks like it's suited for a camera that requires a ton of back focus distance, or if you're doing straight thru viewing without a diagonal. It's a bit overkill for adding just a small distance to bring an accessory into focus.

Baader 31mm Clicklock extension is a nice option. Switching to Clicklocks on Taks has a thread IIRC.


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#20 coopman

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Posted 05 March 2020 - 05:55 PM

I solved my problem. Got some chrome tape & filled up all of the safety grooves.

#21 NickWDavis

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Posted 05 March 2020 - 07:17 PM

My Delos 10, 6, and 3.5 couldn’t achieve focus. Only the 17.3 could

#22 Tyson M

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Posted 06 March 2020 - 12:55 AM

My Delos 10, 6, and 3.5 couldn’t achieve focus. Only the 17.3 could

Yea those 3 require backfocus, the 17.3 requires in focus.  You need an extension tube or a 2" dielectric diagonal and possibly a hi hat adapter.


Edited by Tyson M, 06 March 2020 - 12:55 AM.

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#23 Kunama

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Posted 06 March 2020 - 08:07 AM

Due to the short light path of the small prism you end up with too much backfocus so you need to use a short extension tube ....
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#24 John Huntley

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Posted 08 March 2020 - 05:49 PM

I use a Baader T2 Zeiss prism with my FC-100DL. It works excellently. I connect it to the scope using the Tak 2 inch visual back and the Tak 2 inch - 1.25" adapter with the compression ring fitting. The diagonal has a smooth 1.25" barrel fitted to the scope side and a Baader 1.25" click lock to the eyepiece side. I can bring all my eyepieces to focus with this setup which include 17.3mm and 14mm Delos and the Panoptic 24mm which has a focus point at the same place as the shorter focal length Delos eyepieces.

 

 

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#25 NickWDavis

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Posted 11 March 2020 - 05:34 PM

I use a Baader T2 Zeiss prism with my FC-100DL. It works excellently. I connect it to the scope using the Tak 2 inch visual back and the Tak 2 inch - 1.25" adapter with the compression ring fitting. The diagonal has a smooth 1.25" barrel fitted to the scope side and a Baader 1.25" click lock to the eyepiece side. I can bring all my eyepieces to focus with this setup which include 17.3mm and 14mm Delos and the Panoptic 24mm which has a focus point at the same place as the shorter focal length Delos eyepieces.

Does the click-lock add any length to your diagonal? I’m so close to being able to achieve focus. If I put just the end of the eyepiece barrel in I can see that’s it’s pretty sharp so an extra inch is probably all I need.




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