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Close up images of an Criterion RV-8 Mount

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#1 AaronHenderson

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Posted 15 April 2021 - 08:33 AM

The following was posted on the Facebook "Criterion Dynascope Owners" Group earlier. I thought I would post it here in case others needed this information.

 

I have a RV-8 f6 (it's actually a f6.23) that I am restoring and the previous owner(s) have drastically modified it. I am having problems finding detailed photos of the equatorial head. Could someone please take some close up pictures on your 8" Dynascope for this area. Specifically the RA and Dec. Dial indicators and pointers and general close ups of the head.

 

The pictures need to be from an RV-8 as It's different from the RV-6. The RV-8 has a slow motion knob on the RA axis (you can see the knob in the picture posted of my scope below). If so, I would be in your debt if you could take a few pictures for me that would be awesome. Anytime is fine, I am concentrating on the tube assembly right now and have not gotten to the mount yet? I'll probably 3D print the missing parts, If I can't fabricate them from sheet metal. It's not going to be a stock restore as mine has been so drastically modified. I'm just going for function first and aesthetics second.

This is an on going project. 

 

 

Thanks in advance.

 

IMG_1807 sm.jpeg


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#2 mpsteidle

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Posted 15 April 2021 - 08:46 AM

What an interesting counterweight!


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#3 P_Myers

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Posted 15 April 2021 - 08:48 AM


necessity is the mother of invention.....smile.gif
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#4 DAVIDG

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Posted 15 April 2021 - 08:50 AM

 The RV-6 and RV-8 mounts are just about the same. The only differences are that the Dec shaft is longer and the of course the rings are sized for a larger tube.  

   Here are pictures of the slow motion Dec control on my RV-6 which was an option and the same that came on a RV-8. 

 

                  - Dave 

 

criterion slow motion 2.jpg

criterion slow motion 1.jpg


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#5 AaronHenderson

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Posted 15 April 2021 - 08:56 AM

What an interesting counterweight!

 

 

necessity is the mother of invention.....smile.gif

 

LOL, yep, I'm in the process of making some counterweights. That rig was just so I could take some pictures LOL.  This has been quite the project. Did anybody see the two focusers on the OTA?

 

Cheers,

Aaron


Edited by AaronHenderson, 15 April 2021 - 09:00 AM.

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#6 AaronHenderson

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Posted 15 April 2021 - 09:00 AM

 The RV-6 and RV-8 mounts are just about the same. The only differences are that the Dec shaft is longer and the of course the rings are sized for a larger tube.  

   Here are pictures of the slow motion Dec control on my RV-6 which was an option and the same that came on a RV-8. 

 

                  - Dave 

 

attachicon.gifcriterion slow motion 2.jpg

attachicon.gifcriterion slow motion 1.jpg

Thanks soooo much! I didn't know it was as option for both the RV-6 and RV-8. Those show the pointers that I was looking for. I believe I can make them myself. Do you mind if I share these photos on the Facebook group?

 

Thanks Again!

Aaron



#7 mpsteidle

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Posted 15 April 2021 - 09:07 AM

That "focuser" looks like a crumpled up toilet paper roll...  I'm sure you can find a criterion focuser around here somewhere, they get parted out fairly often.


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#8 DAVIDG

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Posted 15 April 2021 - 09:17 AM

 Your mount is an earlier version since it has the handle on the bolt to adjust the tip of the mount to your latitude. I have seen around 12 to 15, RV-8 over the years and never seen one that was f/6 but did hear of one. The ads, especially the older ones always listed them as F/8 and that is what I saw and that would go with the time frame when you mount was made. So I think the mirror might not be original, especially will all the modifications to the tube.

   You welcome to use my pictures. If you need more I'll be happy to take  some. If you ever get up to Stellafane usually there is a former employee that brought up what was left of Criterion when they closed up. He has boxes of  those pointer and other parts as well that he sells at the swap tables. 

 

                    - Dave 


Edited by DAVIDG, 15 April 2021 - 11:01 AM.

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#9 starman876

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Posted 15 April 2021 - 10:29 AM

The following was posted on the Facebook "Criterion Dynascope Owners" Group earlier. I thought I would post it here in case others needed this information.

 

I have a RV-8 f6 (it's actually a f6.23) that I am restoring and the previous owner(s) have drastically modified it. I am having problems finding detailed photos of the equatorial head. Could someone please take some close up pictures on your 8" Dynascope for this area. Specifically the RA and Dec. Dial indicators and pointers and general close ups of the head.

 

The pictures need to be from an RV-8 as It's different from the RV-6. The RV-8 has a slow motion knob on the RA axis (you can see the knob in the picture posted of my scope below). If so, I would be in your debt if you could take a few pictures for me that would be awesome. Anytime is fine, I am concentrating on the tube assembly right now and have not gotten to the mount yet? I'll probably 3D print the missing parts, If I can't fabricate them from sheet metal. It's not going to be a stock restore as mine has been so drastically modified. I'm just going for function first and aesthetics second.

This is an on going project. 

 

 

Thanks in advance.

 

attachicon.gifIMG_1807 sm.jpeg

that rope holding the counterweight bar is classic in its own rightsmirk.gif


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#10 AaronHenderson

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Posted 15 April 2021 - 11:02 AM

that rope holding the counterweight bar is classic in its own rightsmirk.gif

You can't beat a truckers hitch for holding power - LOL



#11 clamchip

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Posted 15 April 2021 - 11:09 AM

I also own a f/6 the seller's dad bought it new from Criterion.

Serial on the mirror back is #136, motor date is 12-81

Robert

 

post-50896-0-04497100-1409164170_thumb.jpg

post-50896-0-82956700-1409103442_thumb.jpg

post-50896-0-84032800-1409103463_thumb.jpg

post-50896-0-47313000-1409164193_thumb.jpg


Edited by clamchip, 15 April 2021 - 11:26 AM.

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#12 AaronHenderson

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Posted 15 April 2021 - 11:27 AM

 Your mount is an earlier version since it has the handle on the bolt to adjust the tip of the mount to your latitude. I have seen around 12 to 15, RV-8 over the years and never seen one that was f/6 but did hear of one. The ads, especially the older ones always listed them as F/8 and that is what I saw and that would go with the time frame when you mount was made. So I think the mirror might not be original, especially will all the modifications to the tube.

   You welcome to use my pictures. If you need more I'll be happy to take  some. If you ever get up to Stellafane usually there is a former employee that brought up what was left of Criterion when they closed up. He has boxes of  those pointer and other parts as well that he sells at the swap tables. 

 

                    - Dave 

Dave, I think you're spot on about the mirror not being an original, it's in too good of condition to be 55-60 years old. That's some great information and details you provided about this wonderful telescope. I would like to put as much original hardware as I can on it. Thanks again for the pictures and information, Aaron



#13 AaronHenderson

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Posted 15 April 2021 - 11:31 AM

I also own a f/6 the seller's dad bought it new from Criterion.

Serial on the mirror back is #136, motor date is 12-81

Robert

 

attachicon.gifpost-50896-0-04497100-1409164170_thumb.jpg

attachicon.gifpost-50896-0-82956700-1409103442_thumb.jpg

attachicon.gifpost-50896-0-84032800-1409103463_thumb.jpg

attachicon.gifpost-50896-0-47313000-1409164193_thumb.jpg

Thanks Robert! Those are very helpful as well. You can never have too many photos of what the scope should look like when your restoring one of these beauties. 

Aaron



#14 DAVIDG

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Posted 15 April 2021 - 11:57 AM

 Aaron,

   There is  a date stamped in the side of the clock drive motor that will give you a pretty good idea of when the mount was made. 

 

 

                          - Dave 


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#15 apfever

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Posted 15 April 2021 - 01:12 PM

Just pictures.

Attached Thumbnails

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Edited by apfever, 15 April 2021 - 01:21 PM.

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#16 apfever

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Posted 15 April 2021 - 01:40 PM

Aaron,

 

Your DEC slow motion assembly is rotated 90 degrees compared to the other three scopes shown (including mine).  This will be a matter of preference. Your scope has the fine tune knob (on long shaft) straight out for best centered position. The rest of us have both lock knob and fine tune knob kind of further out to reach both.  

 

Your Right Ascension Setting Circles look different.

 

You do not have "CRITERION" engraved into the bottom of the motor cover. This is strange as everything else about your scope says it is an early version. Criterion started with the engraving, then went to a sticker, then went to nothing like yours on the last ones made. You have the short R.A. housing, regular feet instead of moon pads, and fancy schmansy altitude lever lock bolt. All of those items would indicate the first run. 

 

hang on....



#17 AaronHenderson

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Posted 15 April 2021 - 01:41 PM

 Aaron,

   There is  a date stamped in the side of the clock drive motor that will give you a pretty good idea of when the mount was made. 

 

 

                          - Dave 

Dave, here is a picture I took of the motor. It looks like June 1965 "JC665D". It that correct?

 

IMG_2121sm.jpeg



#18 apfever

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Posted 15 April 2021 - 01:59 PM

I don't think that number is a date but I'm not sure.  My motor is EXACTLY the same down to each number and symbol, so I doubt that is a date.   

The Haydon motor was the first one used and much less common than the later Synchron motors.  The Synchron were distinctly dated and much more common so dating the motor is often suggested. I haven't found a dating system for the Haydon.  Your motor is another indicator of first run scopes. 

 

It looks like you have the drive disassembled.  How your clutch is held to the RA shaft is a big indicator of age.  It may be bolted on or held with set screws. The far left RA shaft is threaded on the end. Most of the scopes have a straight shaft end like the rest.   The clutch assembly screws directly onto the threaded shaft, the other assemblies are held on with three setscrews. 

Attached Thumbnails

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Edited by apfever, 15 April 2021 - 02:27 PM.

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#19 AaronHenderson

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Posted 15 April 2021 - 02:01 PM

Aaron,

 

Your DEC slow motion assembly is rotated 90 degrees compared to the other three scopes shown (including mine).  This will be a matter of preference. Your scope has the fine tune knob (on long shaft) straight out for best centered position. The rest of us have both lock knob and fine tune knob kind of further out to reach both.  

 

Your Right Ascension Setting Circles look different.

 

You do not have "CRITERION" engraved into the bottom of the motor cover. This is strange as everything else about your scope says it is an early version. Criterion started with the engraving, then went to a sticker, then went to nothing like yours on the last ones made. You have the short R.A. housing, regular feet instead of moon pads, and fancy schmansy altitude lever lock bolt. All of those items would indicate the first run. 

 

hang on....

Ok, Yes my DEC assembly is rotated, I may position it correctly or leave it there, I don't know yet. The slow motion knob was custom made by the previous owner. I am looking to revert it back to a more stock appearance, except with a larger knob, again time will tell.

 

The RA circles are another modification made by the PO and I have already removed the extra bits. He actually put a slow motion gear and knob. It was not working correctly so I removed it. 

 

I am attaching a picture of "CRITERION" on my motor housing.

 

criterion_cover sm.jpg


Edited by AaronHenderson, 15 April 2021 - 02:09 PM.


#20 apfever

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Posted 15 April 2021 - 02:35 PM

I back track with edits so pictures have been added to my previous post.  Compare your clutch to my pictures. 

 

Woo hoo, with that engrave motor cover - you may have an original oldie.  This is getting good. More in a few hours, have to run now for irrigation stuff before rain and snow.



#21 AaronHenderson

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Posted 15 April 2021 - 03:05 PM

I don't think that number is a date but I'm not sure.  My motor is EXACTLY the same down to each number and symbol, so I doubt that is a date.   

The Haydon motor was the first one used and much less common than the later Synchron motors.  The Synchron were distinctly dated and much more common so dating the motor is often suggested. I haven't found a dating system for the Haydon.  Your motor is another indicator of first run scopes. 

 

It looks like you have the drive disassembled.  How your clutch is held to the RA shaft is a big indicator of age.  It may be bolted on or held with set screws. The far left RA shaft is threaded on the end. Most of the scopes have a straight shaft end like the rest.   The clutch assembly screws directly onto the threaded shaft, the other assemblies are held on with three setscrews. 

I had it disassembled and it did not have any cork in the clutch others have talked about. I lapped the clutch surfaces smooth to get rid of metal on metal grinding that has been going on for who know how long and put plastic milk bottle ring in the clutch and it works better now for holding and letting me move the RA shaft. 

 

My RA shaft is like the one on the far left. It has three set screws (The old set screw holes were stripped and the clutch was attached with epoxy :-/ and I had to tap slightly larger holes and put in new set screws but it was successful ) and has threads on the end that takes a large nut. This is indeed exciting, to know I have an early model. I have it in my kitchen collimating it and getting it ready to use (I'm not through working on it, but I wanted to see how good the optics were) , I may get a chance to have first light on it tonight if the clouds clear up and take a look at the 3 day old moon.  Aaron



#22 Gil V

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Posted 15 April 2021 - 05:26 PM

The differences between RV-6 and RV-8 mounts when I built them were, if memory serves, as follows.

Larger saddle, with longer Dec shaft. 24”, I think.
Dec slow motion control added.
Extra counterweight, if we remembered to put it in the box.

Edited by Gil V, 15 April 2021 - 05:27 PM.

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#23 CHASLX200

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Posted 15 April 2021 - 06:01 PM

It was way too small for my RV8 OTA. 



#24 AaronHenderson

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Posted 16 April 2021 - 07:04 AM

I had first light last night on my vintage RV-8 f6.23. It was wonderful to get this scope under the stars. I did not spend a lot of time collimating it as I will be dismantling it soon for some body work. I just got it lined up and returning the laser. The Moon was an excellent target. It was detailed and crisp and came to a sharp focus as much as the below average seeing would allow. I'm going to love this scope. Fortunately the extra .23 in f ratio did not keep me from coming to focus at infinity. I can also use my 2.4x Dankin Vernonscope Barlow to really push the magnification when the seeing is more favorable. Did I say I love this scope.

 

I'll post some pictures soon of this project.

Aaron


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#25 mpsteidle

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Posted 16 April 2021 - 08:43 AM

There's nothing like a big reflector!  Share some more pictures when you get the chance!


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