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Davidson 10" reflector 1947

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#1 Mr Magoo

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Posted 22 June 2014 - 10:27 PM

Hi folks. I have a chance to buy this scope from the guy who posted here about it back in 2009. Davidson Reflector Archived post He is moving away for retirement and can't take it with him. Just curious to see if anyone has any new thoughts on this. It is a really interesting scope. No mount with it. It still looks the same as when he posted it in '09.

#2 Ducky62

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Posted 23 June 2014 - 12:28 AM

I skimmed the thread. Do you know if Davidson made mounts and sold whole 'scopes? Were they just an ATM parts supplier?
Did Davidson make the mirror and is anything inscribed on it? Can you look through it?

Those are all the deciding questions I'd have if someone offered it to me. Unless it was really cheap, then I'd just buy it and figure it all out later :lol:

#3 apfever

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Posted 23 June 2014 - 02:52 AM

I looked in my 1948 issues of S&T and found nothing. I searched the 40's on the DVD set and found nothing.

So far it is a name on a cast part.

#4 Mr Magoo

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Posted 23 June 2014 - 09:09 AM

I can get it at a good price. I need another big heavy reflector like a hole in my head, but if you saw it in person I think you would do the same. The construction on it is interesting. I really don't think it was an ATM scope. I am starting to wonder if it was part of a larger rig. One thing thing I noticed is that there are no other holes in the OTA where a finder may have been mounted.

#5 Mr Magoo

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Posted 04 August 2014 - 11:28 PM

Well, I go to pick this scope up tomorrow. With some help that is since I'm still recovering from surgery and on a weight restriction. My friend that owns it told me to just come get it out of his way for free! Can't beat free especially since I don't have telescope funds right now. I'm really intrigued by the history of this scope. Wish I could find out where it came from. Going to have to build some kind of mount for it. 


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#6 Mr Magoo

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Posted 05 August 2014 - 04:57 PM

Picked up the scope today. I will try and get some pictures of it up. There were some pictures in the archived thread that my friend who I got it from posted in 2009, but looks like we can't get at them yet. This is one big mystery scope for sure. 


Edited by Mr Magoo, 05 August 2014 - 04:57 PM.


#7 Mr Magoo

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Posted 05 August 2014 - 05:05 PM

Here is one picture of the OTA which is all I got, no mount. Attached File  005-001.JPG   474.91KB   1 downloads


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#8 Deven Matlick

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Posted 05 August 2014 - 05:22 PM

Here is one picture of the OTA which is all I got, no mount.

 

Well that's different...



#9 Mr Magoo

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Posted 06 August 2014 - 08:48 PM

Spent some time disassembling the scope today. After working with it I really feel that this scope is a total ATM scope. There are several things that lead me to believe this. For starters, most all of the metal pieces have layout scribe lines on them for the screw holes. You generally would not see that on a commercial product. There are even centering lines molded in reverse, in the cast aluminum mirror cell for the collimation bolt holes. I think that a person with the name F. Davidson built all of this scope in 1947 and cast their name and date right on the mirror cell I also believe that 99% of what I have has been with the OTA since it was built.

 

The tube sections are some sort of a resin tube. I really don't know how or what to describe it. The color of the tube is black inside and does not seem to be painted. It is very smooth with no spiral pattern like on my Criterion OTA's. I really can't see layers even in the end cut.

 

Now for some pictures. I'll start with the cast aluminum mirror cell. Very interesting design. Each brass collimation bolt is spherically ground on the end and a hole drilled in it to receive a brass nail. The back side of the little triangles are machined with a reverse counter sunk hole that is spherical so that if can pivot on it making it able to pivot. The centering pieces on the sides are basically the same except that they use a allen head set screw. The collimation knobs appear to be handmade. No two are exactly the same.

 Attached File  004.JPG   486KB   0 downloads


Edited by Mr Magoo, 06 August 2014 - 09:39 PM.


#10 Mr Magoo

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Posted 06 August 2014 - 08:50 PM

Flotation triangles and centering pads. Attached File  006.JPG   484.53KB   0 downloads



#11 Mr Magoo

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Posted 06 August 2014 - 08:51 PM

Support triangles. 

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#12 Mr Magoo

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Posted 06 August 2014 - 08:52 PM

Centering pad.

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#13 Mr Magoo

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Posted 06 August 2014 - 08:54 PM

You can see the layout lines for the hole. They must have been etched into the casting mold. 

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#14 Mr Magoo

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Posted 06 August 2014 - 08:56 PM

Outside of cell. I don't think it was originally painted. Someone did a crude job of masking off all of the holes and spraying it while it as all assembled. 

 

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#15 mdowns

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Posted 06 August 2014 - 08:59 PM

Ken,

 Will this one become another dob for you or do you have something else in mind?



#16 Mr Magoo

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Posted 06 August 2014 - 09:00 PM

Now for the spider. Again, appears to be all ATM. I don't think the vanes are original. They are made of banding 1.25" wide. The machined aluminum hub is 1.5" long and not painted where the vanes attach on. I think they were replaced. Each vane position has a letter stamped into the hub and there is a corresponding letter etched inside the tube where it attaches.

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#17 Mr Magoo

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Posted 06 August 2014 - 09:04 PM

Ken,

 Will this one become another dob for you or do you have something else in mind?

Well Mike, I'm loathe to chop up any old scope, so I'm going to try and use what is here and build a mount for it. Not sure if you know our member Eric Allen or not, but he is an experienced mirror maker and I'm going to see if he will test the mirror for me to see what it is like. I should have mentioned that the scope is a 10" f/8. Coatings are not great, but for now they will have to do. 


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#18 Mr Magoo

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Posted 06 August 2014 - 09:07 PM

Here is a close up of the secondary holder. It pivots on one hinge and has a brass knurled thumb screw with a spring opposite of it. Not sure how easy it is to collimate like this. I don't think this arrangement is all original either. Notice the top of the hub, unpainted and there are 4 taped holes there for something. I'm thinking there was another disk mounted there or something. The washers don't jive with the rest of the scope build either. Most all of the hardware is brass. 

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Edited by Mr Magoo, 06 August 2014 - 09:09 PM.


#19 Mr Magoo

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Posted 06 August 2014 - 09:11 PM

This is the secondary holder disassembled. It is a 2" secondary and also has the initials F.D. in pencil on the the backside. I want to know who F.D. is!

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#20 mdowns

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Posted 06 August 2014 - 09:14 PM

Ken,

 I do know Eric and Roberta and enjoyed thier company and 24" while I was there in May. BTW,I cant recommend Spectrum coatings enough should you choose to recoat. Good luck!



#21 Mr Magoo

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Posted 06 August 2014 - 09:17 PM

Now for my favorite part, the focuser! All machined brass helical focuser. I don't know the proper name for this style. It is a helical focuser, but the center tube does not rotate. It moves like butter. It has a separate base that is machined to the O.D. of the OTA. 

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#22 Mr Magoo

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Posted 06 August 2014 - 09:18 PM

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#23 Mr Magoo

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Posted 06 August 2014 - 09:19 PM

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#24 Mr Magoo

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Posted 06 August 2014 - 09:21 PM

This eyepiece was in the focuser. I'm guessing it a Ramsden. 1.25" and I'm assuming made by F. Davidson. No markings on it at all. 

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#25 Mr Magoo

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Posted 06 August 2014 - 09:22 PM

Last one for tonight. Flip side. 

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