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Anyone Recognize This Focal Reducer (Maybe)?

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11 replies to this topic

#1 Tom Duncan

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Posted 26 November 2019 - 09:03 PM

Got this with a bunch of older astro stuff, mostly Takahashi, looks to be a focal reducer or some such. 

 

No ID markings on it at all. Inside threads on the end that looks to be the end that accepts a camera or some such are 42mm (peak to peak) but NOT Pentax thread. Likely the threads of whatever go into this will measure close to 43mm. I would think the threads would be designation 43mm. I notice Takahashi used 43mm threads a lot. 

 

Male threads on the other end that likely goes into the scope drawtube are 60mm.

 

Glass appears to be multi-coated, probably a singlet but might be a doublet (the edge of the element/group is not easy to see). Element/group is convex on the scope side, looks to be flat or nearly so on the camera side. 

 

A Google Image search on "Takahashi focal reducer" didn't help, nothing that looked like this. I'd be surprised if this a Tak product, I don't think I've ever gotten anything Tak that didn't have their name on it. 

 

Anyone know who made this and what scopes it goes to? 

 

Thanks

 

Tom Duncan 

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#2 noisejammer

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Posted 28 November 2019 - 10:24 PM

I have a Tak field flattener on my e-160, It uses a M60x0.75 thread to mount, I think the same applies to the e-130 & e-180. These don't have the Tak logo on them.

 

Your optic is too small for the FS 102. If I was to guess, I'd take a flier at a field flattener for something like a 60, 76 or 90 mm doublet.

 

BTW - Are you sure the smaller thread isn't M42x0.75? This is the common T2 thread. (Pentax is M42x1).



#3 Tom Duncan

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Posted 29 November 2019 - 07:36 PM

Definitely not T-threads, too large, a T-threaded piece just drops in loosely, no thread engagement at all. I'm pretty sure this would be designated as 43mm threads. Pitch is 1.0mm, so the proper designation would be M43x1.0. The male threads on the other end are M60x0.75 so that looks promising. 

 

I see Tak makes extenders as well as reducers and field flatteners, not sure which this would be...any way to test for this without having the proper scope? 

 

I found this Tak piece on the Land, Sea & Sky website, labeled "TAKAHASHI F/3 0.6X REDUCER", described as "The Takahashi 0.6X reducer converts the FSQ-106 and -130 refractovers (sic) to f/3 optical systems for use in astrophotography"...only $1640 (!):

 

( https://www.landseas...6x-reducer.html )

 

I have an email into L,S & S with a photo, I'm assuming I won't hear back any earlier than Monday. 

 

Tom 



#4 noisejammer

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Posted 01 December 2019 - 10:15 AM

I see Tak makes extenders as well as reducers and field flatteners, not sure which this would be...any way to test for this without having the proper scope? 
 

A reducer is a positive lens, so i should be able to focus a light bulb onto you hand.

A field flattener is usually a weak negative lens and won't focus light.


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#5 Tom Duncan

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Posted 02 December 2019 - 12:59 PM

It won't focus an image of a light bulb on my hand so it's a likely a flattener then, at least between a flattener and a reducer. How about a check for an extender?

 

Thanks for the tip on that, helpful. 

 

Tom 



#6 TxStars

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Posted 03 December 2019 - 07:05 PM

That is not for a Tak FSQ anything, It is far too small..   lol

 

 

**It might be for the 60mm refractor..

Part # 18

Or

Part # 80

https://static.shopl...ystem-chart.pdf

 

**Edit**

It is not for the 60mm refractor either

The threads are in the wrong places.

Likely not a Tak product unless they have a visual only corrector, which I have not seen yet.


Edited by TxStars, 03 December 2019 - 07:25 PM.


#7 noisejammer

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Posted 04 December 2019 - 11:38 PM

It won't focus an image of a light bulb on my hand so it's a likely a flattener then, at least between a flattener and a reducer. How about a check for an extender?

 

Thanks for the tip on that, helpful. 

 

Tom 

You're welcome

An extender is a fairly weak negative lens. Look through it and things should appear further away.



#8 edif300

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Posted Yesterday, 05:13 AM

Pentax?



#9 MGD

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Posted Yesterday, 10:44 AM

I think it's the f8 corrector for the mt130 newt.

Mike



#10 Tom Duncan

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Posted Yesterday, 03:31 PM

You're welcome

An extender is a fairly weak negative lens. Look through it and things should appear further away.

Hard to say, but it appears the image is magnified slightly with it held at arms length. 

 

Tom



#11 Tom Duncan

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Posted Yesterday, 03:47 PM

I think it's the f8 corrector for the mt130 newt.

Mike

I think we're getting closer. I see there are many iterations of the MT, 130, 160 and 200 at least. I found one 'reducer' that looked right except for the crosshatch vs ribs on the outer edge. 

 

Tom 



#12 TxStars

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Posted Yesterday, 08:47 PM

It does not have the threads in the correct locations to be one of the f/8 correctors.

 

MT_f8_corrector.jpg

 

And the end with the female threads is too small for it to be one of the Epsilon / MT / FC  correctors.

 

It could be a Nikon or Borg part?

 

Does the knurled ring thread off ??


Edited by TxStars, Yesterday, 08:54 PM.



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