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Edmund 8" f/8

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#26 Bomber Bob

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Posted 03 June 2021 - 03:37 PM

Nice work, Zane!  I bet the views are eye-watering.  Gotta Love Edmund.


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#27 starman876

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Posted 03 June 2021 - 04:27 PM

Looks beautiful Zane.   Looks like a keeper to me.  First one I have ever seen.


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#28 Augustus

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Posted 03 June 2021 - 04:46 PM

It really looks great.

I've never seen one in such nice and original condition.

That is a real treasure you have there.

 

Robert

Thank you! You really think so? I knew these scopes weren't common but now I'm beginning to wonder if more than a couple hundred complete units ever sold - if that.

 

Yes  agree   it looks great   even better cleaned up      nuf said on the ota   Anyone should be proud to have it

As mentioned before   we really like that patina    that off white color is sweet...

enjoy it

Thank you! I'm gonna bring it with the Fecker to the BBQ at WAS on the 15th if you wanna have a look through either! 

 

Nice work, Zane!  I bet the views are eye-watering.  Gotta Love Edmund.

Thank you! I sure hope so! Will find out soon.


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#29 CHASLX200

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Posted 03 June 2021 - 06:18 PM

The included 7x50 finder with this thing is really odd - huge 2" eyepiece with seemingly no field stop, AFOV in excess of 90 degrees. I wonder how it does at night.

Finder makes a good one eye sweeper. I used to hand hold mine for sweeping. Very wide FOV.


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#30 geovermont

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Posted 03 June 2021 - 07:38 PM

It would be great fun viewing Mars through that beauty at the next opposition. Jupiter, Saturn, the prominent globulars, all should be pretty nice if the mirrors are of decent quality.


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#31 davidmcgo

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Posted 03 June 2021 - 08:16 PM

Those finders are about 5x or 6x with a 12 degree field and do get blurry off axis.  The eyepieces were surplus anti aircraft gun sights and objectives were either from same or 7x50 binocular objectives.

 

Dave


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#32 apfever

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Posted 03 June 2021 - 09:47 PM

On the serious side should the eyepieces be checked for radioactivity?   I have one of those old brass military surplus eyepieces for collector purposes. I keep it in the original metal lined cloth shipping bag, and then foil wrap the box. Mine will rock a Geiger counters world big time. 


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#33 Augustus

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Posted 03 June 2021 - 10:25 PM

On the serious side should the eyepieces be checked for radioactivity?   I have one of those old brass military surplus eyepieces for collector purposes. I keep it in the original metal lined cloth shipping bag, and then foil wrap the box. Mine will rock a Geiger counters world big time. 

It kind of looks like it has thorium coatings, and it has weird schmutz on the eye lens that's difficult to clean off. 


Edited by Augustus, 03 June 2021 - 11:32 PM.


#34 clamchip

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Posted 03 June 2021 - 10:56 PM

Thorium was used in the glass recipe and usually by now it will have decomposed

and tinted the glass to a tea color.

If anyone is planning to use a suspect lens have it tested. They are dangerous because

your eye is a easy entrance into your body.

Years ago a favorite of mine was Kodak Aero Ektar recon camera lenses. These used

a Thoriated element.

We would buy these lenses from surplus stores and camera shops who seemed to like

using the big heavy lens for door stops.

Us kids would build richest field telescopes with them. Quite a good deal on a 50 cents

a week income.

Robert

 

post-50896-0-02565900-1532906656.jpg


Edited by clamchip, 03 June 2021 - 11:03 PM.

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#35 Augustus

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Posted 03 June 2021 - 11:01 PM

Thorium was used in the glass recipe and usually by now it will have decomposed

and tinted the glass to a tea color.

If anyone is planning to use a suspect lens have it tested. They are dangerous because

your eye is a easy entrance into your body.

Years ago a favorite of mine was Kodak Aero Ektar recon camera lenses. These used

a Thoriated element.

We would buy these lenses from surplus stores and camera shops who seemed to like

using the big heavy lens for door stops.

Us kids would build richest field telescopes with them. Quite a good deal on a 50 cents

a week income.

Robert

 

attachicon.gifpost-50896-0-02565900-1532906656.jpg

Hmmm, where could I find someone with a Geiger counter?


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#36 JamesDuffey

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Posted 03 June 2021 - 11:12 PM

Hmmm, where could I find someone with a Geiger counter?

High School or College physics department. 


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#37 Augustus

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Posted 03 June 2021 - 11:41 PM

First thing to do is take the finder apart and see if the lenses are really all that brown. If they are I will try to find somebody with a Geiger. If they aren't, I think it's safe to assume there's nothing radioactive.


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#38 highfnum

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Posted 04 June 2021 - 12:58 AM

nice catch

its big!



#39 CHASLX200

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Posted 04 June 2021 - 05:38 AM

I used mine for years and never even get a cold. 



#40 starman876

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Posted 04 June 2021 - 07:16 AM

I used mine for years and never even get a cold. 

there are other issues that occur from radioactive contamination.  You wont know until it is too late. 


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#41 Augustus

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Posted 04 June 2021 - 10:11 AM

While it does look like there is coating failure on the eye lens, all surfaces are perfectly clear and devoid of tint, so safe to assume they’re not thorium glass
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#42 Terra Nova

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Posted 04 June 2021 - 10:27 AM

To my knowledge, the 50mm Edmund Super Finder of the 1960s used this heavy brass 30mm WideField Kellner that was originally part of an anti-aircraft gun sight. They did not use thoriated glass. Here’s mine. It’s one of my absolute favorite eyepieces! It may be a Reverse Kellner as it totally delivers that ‘spacewalk’ impression in my 6” Newtonian RFT, my TV Genesis SDF, and the ST120 I used to have.

Attached Thumbnails

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#43 Augustus

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Posted 04 June 2021 - 10:34 AM

To my knowledge, the 50mm Edmund Super Finder of the 1960s used this heavy brass 30mm WideField Kellner that was originally part of an anti-aircraft gun sight. They did not use thoriated glass. Here’s mine. It’s one of my absolute favorite eyepieces! It may be a Reverse Kellner as it totally delivers that ‘spacewalk’ impression in my 6” Newtonian RFT, my TV Genesis SDF, and the ST120 I used to have.

Mine looks exactly like that! I did notice it can be removed from the finder without taking the crosshairs with it - which means I suppose it works as a scope eyepiece. The one thing to note is there's a notch on the barrel used for focusing.


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#44 clamchip

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Posted 04 June 2021 - 10:39 AM

I have a Deluxe finder and it's a favorite of mine.

And I have just about everything I need to assemble a Edmund 8" f/8 except I need the tube.

Yes they are scarce. They were expensive.

Robert

 

post-50896-0-78994200-1571696943_thumb.jpg


Edited by clamchip, 04 June 2021 - 10:41 AM.

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#45 clamchip

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Posted 04 June 2021 - 10:46 AM

One of the many great features of the 8" f/8's 'Extra Heavy Duty' mounting is the pedestal

is standard 4 inch NPT so you can buy sections of pipe and make it taller to refractor height.

Robert

 

post-50896-0-09084200-1545870196.jpg

 


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#46 clamchip

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Posted 04 June 2021 - 10:51 AM

Here's a 1962 Edmund catalog with the introduction of the 8"f/8 I think it

was actually 1961:

 

https://wiki.telesco...2-3_Catalog.pdf


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#47 clamchip

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Posted 04 June 2021 - 10:59 AM

Zane the motor should have a date.

Robert

 

post-50896-0-11105800-1432935439_thumb.jpg


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#48 highfnum

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Posted 04 June 2021 - 11:06 AM

hey Zane

I got a rad counter

 

i


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#49 Terra Nova

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Posted 04 June 2021 - 11:08 AM

As far as I remember, the 8” Edmund came with a set of three 1.25” Edmund (circle T) volcano-top Orthoscopic eyepieces and the Edmund Barlow.



#50 Terra Nova

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Posted 04 June 2021 - 11:14 AM

At $389 in 1962 (and remember, that didn’t include shipping which was F.O.B.), that would have been a months take-home wages for someone in an entry-level professional career (~$5000 per year). It wasn’t by any means, a cheap telescope.


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