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what distance betting objective

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#1 jack savard

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Posted 03 May 2005 - 06:33 PM

I am in the process to built a binocular whit two 90mm triplet objective at about 350 mm FL

I built it whit mirror and my question is about how much distance I can put betting the two objective

if I put it at maximun I have something like 15 inch betting the two or I can put it very near something like 6 inch look like my ordinary 25X100

do i have a better perpective at 15 inch
or nothing better

advise please

:tonofbricks:

#2 edcannon

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Posted 03 May 2005 - 07:40 PM

I'm going to attempt a reply. I think instead of "betting" you mean "between", so your question is how far apart your objectives should be on your home-made 90mm binocular. I can only guess on the correct answer to that question, but I would think that there would not be much to gain by setting them far apart, as your targets in astronomy are at "infinity" in terms of lens focus. I would think that there would be no reason to have them any farther apart than the minimum distance to allow them to work mechanically.

Good luck!

Ed Cannon - Austin, Texas, USA

#3 Guest_**DONOTDELETE**_*

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Posted 04 May 2005 - 06:40 AM

I believe this forum had a discussion on the visual effects of changing the objective spacing many months ago. A forum search could probably dig it up if anyone is interested.

#4 EdZ

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Posted 04 May 2005 - 07:47 AM

That was relative to the close focusing of terrerstrial viewing and pertained to depth of field. Very good discussion, however it would not pertain to viewing at infinity.

I agree with Ed C, no benefit for astro observing.

edz

#5 Guest_**DONOTDELETE**_*

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Posted 04 May 2005 - 11:49 AM

Oh yeah. That was it. Excellent recall EdZ...or did you cheat and look it up? ;)

#6 EdZ

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Posted 04 May 2005 - 01:05 PM

While I struggle to remember the names of people that walk by my desk every day whom i've worked with for 10-15 years, that little nugget was stuck in some otherwise unused brain cell.

edz


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