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New to me 8” 1940s needing refurb

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#1 Cato85

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Posted 24 September 2020 - 10:11 AM

Hi and thanks in advance for any input. 
 

I've recently been gifted a what appears to be completely hand built 1940s 8” Newtonian refractor. I’m really keen on refurbishing and getting it to be a viewable instrument to introduce my kids into astronomy with history. I have a decent deal of experience with newer technology but have never touched anything older than 10 years. Any insight is greatly appreciated. 
 

what’s in the boxes:

60”x8-1/2” tube with spotter mount up to 1-3/4”

focal length from primary to secondary mirror 45-1/2”

tripod with counterweights

rack and pinion equatorial mount made by watts

4 eye pieces

4 prisms of various size types and finish

8” main mirror encased in non removable housing

 

all optics require cleaning/alignment as this has been in storage for the last 30 years. 
I’m trying to ascertain what I’m missing from the mount as it uses a third reflecting mirror Or prism so the user doesn’t need to stand on a viewing staircase. 

 

considering it’s age it’s in pretty good shape. 

Any pointers on where to start?

How should I clean the primary reflector as it’s encased in wood and I don’t want it to swell and distort the mirror?
 

 

EDIT: How should I clean this vintage mirror I.e. collodion, dish soap with d.i. Waters, or other means and how could I identify a older collodion coating on the surface?

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Edited by Cato85, 24 September 2020 - 06:45 PM.

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#2 starman876

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Posted 24 September 2020 - 10:24 AM

welcome to cloudy nights.  Looks like a very interesting telescope.



#3 Cato85

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Posted 24 September 2020 - 10:36 AM

Thank you I’m happy to be here. It’s definitely unique. 



#4 tim53

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Posted 24 September 2020 - 11:05 AM

Hi and thanks in advance for any input. 
 

I've recently been gifted a what appears to be completely hand built 1940s 8” Newtonian refractor. I’m really keen on refurbishing and getting it to be a viewable instrument to introduce my kids into astronomy with history. I have a decent deal of experience with newer technology but have never touched anything older than 10 years. Any insight is greatly appreciated. 
 

what’s in the boxes:

60”x8-1/2” tube with spotter mount up to 1-3/4”

focal length from primary to secondary mirror 45-1/2”

tripod with counterweights

rack and pinion equatorial mount made by watts

4 eye pieces

4 prisms of various size types and finish

8” main mirror encased in non removable housing

 

all optics require cleaning/alignment as this has been in storage for the last 30 years. 
I’m trying to ascertain what I’m missing from the mount as it uses a third reflecting mirror Or prism so the user doesn’t need to stand on a viewing staircase. 

 

considering it’s age it’s in pretty good shape. 

Any pointers on where to start?

How should I clean the primary reflector as it’s encased in wood and I don’t want it to swell and distort the mirror?
 

What you have there is a Springfield telescope.  It's a wonderful Russell Porter design.  A complete restoration of the scope would be my recommendation.  Do you have any information on who built it?  1940 sounds about right.  The design was popularized based on the Scientific American Amateur Telescope Making volumes 1 and 2 in the. 1920s and 1930s. 

 

I built one in 1981 based on those articles.  

post-6788-14073028371432_thumb.jpg

 

Check out:  https://stellafane.org/. (My internet connection is poor this morning, so I can't search out the specific pages covering the Springfield mount)

I also have a thread I started when I had just acquired a large Springfield mount head.  Sadly, I still haven't built a scope for it yet, but there are a lot of pics of various Springfield telescopes in there:  https://www.cloudyni...ingfield tim53

 

Others could also chime in with thoughts.  You might also consider contacting the Antique Telescope Society.  Some of their members are on here, and I hope they chime in as well.

 

-Tim.


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#5 tim53

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Posted 24 September 2020 - 11:08 AM

Here's a picture of Porter's 6" Springfield that is at Stellafane.  This one is most similar to what you have:

 

post-6788-1407302877812_thumb.jpg


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#6 starman876

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Posted 24 September 2020 - 11:15 AM

I thought the scope design lookes familiar.  Thanks Tim.  Awesome scope.


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#7 Cato85

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Posted 24 September 2020 - 12:05 PM

I’m absolutely ecstatic and immensely grateful for the information so I can research into it.



#8 Defenderslideguitar

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Posted 24 September 2020 - 12:11 PM

Cato85

Welcome aboard  you have come to the right place...………..congrats  that is so cool.

That is  a tremendous find...… looks like you want to get it up and working which is wonderful......if something like this gets thrown in  a dumpster when someone cleans out a place  not knowing what it was or what it could be  it is lost to history. Agree with Tim   it deserves a restore...…



#9 JamesMStephens

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Posted 24 September 2020 - 12:49 PM

Newtonian reflector, not refractor.  (Typo, I know smile.gif )  Terrific find!

 

Jim


Edited by JamesMStephens, 24 September 2020 - 12:50 PM.


#10 oldmanastro

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Posted 24 September 2020 - 02:34 PM

What a wonderful gift and restoration project. I read about the Springfield mount for the first time with in my ATM books and always admired Clarence P Custer telescope. The photo appeared in many books. Just sitting comfortably and not having to move with the eyepiece seems so nice. I wish you the best on this project. 


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#11 tim53

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Posted 24 September 2020 - 03:46 PM

An ultimate:  https://alaskaapplie...blue-telescope/


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#12 pbealo

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Posted 25 September 2020 - 09:38 AM

Are you in VT or western NH near the Connecticut River? I ask only because I wonder if the castings for that mount originated from the Stellafane group??

 

You might also reach out to Matt Considine who curates the Telescope Making Museum in Springfield. PM me for his email.

 

Peter


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#13 Cato85

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Posted 25 September 2020 - 12:30 PM

Are you in VT or western NH near the Connecticut River? I ask only because I wonder if the castings for that mount originated from the Stellafane group??

 

You might also reach out to Matt Considine who curates the Telescope Making Museum in Springfield. PM me for his email.

 

Peter

Thank you Peter, Matt beat me to the button and contacted me. I’m really excited about the project. I’ve already begun working on the four eyepieces and tonight I’ll be working on the tube and cleaning the main reflector. I’ve acquired this instrument here in Iowa... I know one of the worst places to get consistent observing nights. 
 

-Phillip 


Edited by Cato85, 25 September 2020 - 12:31 PM.

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#14 steve t

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Posted 25 September 2020 - 01:14 PM

Welcome, you'll find that there are a lot knowledgeable folks in this group.

Wow, looks like you may have a cool piece of telescope making history.



#15 mconsidine

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Posted 25 September 2020 - 04:28 PM

For anyone interested, take a look at pages 30-33 of an early (non-reprint) version of Ingalls/Porter's "Amateur Telescope Making" (ie not the "Advanced" or "Book III" versions)

 

There are obviously similarities, but also some differences from those drawings.  The set screw for the counterweight is located in a slightly different spot.  And the base the provides the elevation seems to be constructed differently, as is the RA disc (ie the drawings show it "domed").  My initial reaction is that the eyepiece area has been modified/upgraded/changed, but I think we need more photos.  Also, is the mirror cell a new item?  It may mean that the mirror is too.

 

There were blueprints produced by the club, but I don't have copies handy.  It's entirely possible that they differed from the drawings above and showed some elements simplified.  There was at least one "simplified" version of the mount drawn, but I don't recall that it looks like this instrument.  I'll try to find those for a comparison.  But the upshot is that the basic principles are pretty straightforward, so someone could easily start with the blueprints and develop a few shortcuts along the way.

 

If you are going to clean anything and can take the mirror out of its cell, it would be worth carefully examining the edge and back for any writing or inscription.  I suppose the original could have been Pyrex, but equally likely plate glass (?).  If it were plate glass then I'd guess its also an original mirror.  But that would just be a starting point.  And it's just my 2 cents.

 

Matt


Edited by mconsidine, 25 September 2020 - 04:38 PM.

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#16 pbealo

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Posted 25 September 2020 - 04:42 PM

Plate glass would be indicated by it being "white" when viewed through the edge. Pyrex is greenish.



#17 Cato85

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Posted 25 September 2020 - 05:19 PM

For anyone interested, take a look at pages 30-33 of an early (non-reprint) version of Ingalls/Porter's "Amateur Telescope Making" (ie not the "Advanced" or "Book III" versions)

 

There are obviously similarities, but also some differences from those drawings.  The set screw for the counterweight is located in a slightly different spot.  And the base the provides the elevation seems to be constructed differently, as is the RA disc (ie the drawings show it "domed").  My initial reaction is that the eyepiece area has been modified/upgraded/changed, but I think we need more photos.  Also, is the mirror cell a new item?  It may mean that the mirror is too.

 

There were blueprints produced by the club, but I don't have copies handy.  It's entirely possible that they differed from the drawings above and showed some elements simplified.  There was at least one "simplified" version of the mount drawn, but I don't recall that it looks like this instrument.  I'll try to find those for a comparison.  But the upshot is that the basic principles are pretty straightforward, so someone could easily start with the blueprints and develop a few shortcuts along the way.

 

If you are going to clean anything and can take the mirror out of its cell, it would be worth carefully examining the edge and back for any writing or inscription.  I suppose the original could have been Pyrex, but equally likely plate glass (?).  If it were plate glass then I'd guess its also an original mirror.  But that would just be a starting point.  And it's just my 2 cents.

 

Matt

 

Plate glass would be indicated by it being "white" when viewed through the edge. Pyrex is greenish.

It’s a blue tinted type of glass. To my knowledge it’s a very pure type of glass. Without any engraving/markings or sticker. More pictures of the mount coming in the next hour or so with a quick sketch and measurements. 


Edited by Cato85, 25 September 2020 - 05:20 PM.

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#18 tim53

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Posted 25 September 2020 - 05:33 PM

I do have a set of blueprints for the Springfield mount that I got from my late friend Dick Zanteson from JPL about 25 years ago.  If others can't find them, I can try to upload my copy.



#19 mconsidine

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Posted 25 September 2020 - 06:42 PM

Tim53 - could you post or email to me the drawings you have?  I'd be interested in seeing how they compare.

 

All - At Springfield we have a blueprint that was mailed out to those inquiring about the mount, on the heels of the publication of Porter's Scientific American articles and ATM book.  John Pierce initially made them available and then after he died I think a guy in Michigan (John Holmes) had some.  The design was intended by Porter to be a gift to the amateur community, so if I can get a decent image of a full blueprint, I'll post it.  The images I do have don't "mosaic" well due to the conditions under which I photographed them.

 

Matt

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#20 tim53

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Posted 25 September 2020 - 07:15 PM

I'll try to remember to do that before we head out for a week of some vacation time.  I seem to remember it's very similar to what you posted, and also dated 1926.  But I'll try to verify.



#21 mconsidine

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Posted 25 September 2020 - 07:42 PM

The original-original version has John Pierce's address in the place of Holmes'...

#22 Cato85

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Posted 25 September 2020 - 07:51 PM

Here’s photos and hand sketch’s with measurements. Last photos are of the primary reflector. 

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#23 Cato85

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Posted 25 September 2020 - 07:54 PM

More. 

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#24 mconsidine

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Posted 25 September 2020 - 07:55 PM

That's a bit of a variant I don't think I've seen before. Ie the latitude adjustment ...

#25 Cato85

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Posted 25 September 2020 - 07:56 PM

Main reflector. 

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