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Kenton "Kencor 4000/C5-8C Precision Telescope Drive" - Celestron C8

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#1 Tom Duncan

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Posted 23 July 2021 - 06:52 PM

Picked up this old Celestron C8 fork/base assembly (no OTA) recently, looking for information about it.

 

From this AM ad of 2012 it would seem the lower half of the base is an aftermarket "Kenton Kencor 4000/C5-8C Precision Telescope Drive" utilizing giant dual worm drives and a very thick 7" driven gear but that's all the info I could find with a cursory internet search. Assuming one of the motors is inside the base the other is hanging off the side. Hard to tell due to the shrouding but the worm looks to be about 1.135" diameter and the driven gear 1/2" thick. 

 

I plugged it in and stood back, it just ran, didn't blow up. In one hour it moved one hour on the scale. These old clock motors are really bulletproof!

 

Any info appreciated, I'd like to know more about this mount accessory.  

 

Tom Duncan 

 

 

Attached Thumbnails

  • KENCOR-1-A.jpg
  • DSC_KENCOR-2-A.jpg
  • KENCOR-3-A.jpg
  • KENCOR-4-A.jpg

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#2 kansas skies

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Posted 23 July 2021 - 07:05 PM

I've never seen anything like this - but I like it...

 

Bill



#3 Creedence

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Posted 23 July 2021 - 07:15 PM

Found this on Astromart (though you may have come across this in your search, so forgive me if you already have this information).  An original owner of the system had it listed some time back for $225:

 

Kenton Engineering Kencor 7700 Astro camera drive (original owner) for sale
includes 7' 120V AC power cord
includes optional 5x24 right angle polar finderscope
Includes 2 sheets with operating instructions plus copy of pertinent pages from original sales brochure

It has precision 2-stage worm reduction (sector main gear) - extremely accurate guaranteed to not exceed 15arc seconds peak to peak periodic error
It has high-torque permanent magnet synchronous motor
Dimensions = 4"x6"x8"
Weight ~ 3.5 pounds
Mounts to tripod via 1/4"-20 screw thread
in excellent to mint condition both cosmetically and mechanically



#4 Tom Duncan

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Posted 23 July 2021 - 07:31 PM

Found this on Astromart (though you may have come across this in your search, so forgive me if you already have this information).  An original owner of the system had it listed some time back for $225:

 

Kenton Engineering Kencor 7700 Astro camera drive (original owner) for sale
includes 7' 120V AC power cord
includes optional 5x24 right angle polar finderscope
Includes 2 sheets with operating instructions plus copy of pertinent pages from original sales brochure

It has precision 2-stage worm reduction (sector main gear) - extremely accurate guaranteed to not exceed 15arc seconds peak to peak periodic error
It has high-torque permanent magnet synchronous motor
Dimensions = 4"x6"x8"
Weight ~ 3.5 pounds
Mounts to tripod via 1/4"-20 screw thread
in excellent to mint condition both cosmetically and mechanically

Thanks Creedence, not sure why that ad didn't show up with a Google search. Looks like I have part of the same setup though in his the drive corrector is not Kenton and the model of the drive is 4000, not 7700. And his is much earlier if the serial number means anything, 227 vs 4228. 

 

Tom 



#5 gnabgib

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Posted 23 July 2021 - 07:49 PM

Tom;

      I too have one of the drive bases.  They are well built and offer a huge improvement in tracking accuracy compared the the original Celestron  spur gear drive system.  I am not sure how many were made but in my 50+ years of telescope making and using yours makes the third unit I have come across.  So they SEEM pretty rare BUT look at your serial number then look at mine.  I do not know what to make of this.   My unit also has a thumb knob under the worm block to allow disengaging/ adjusting the worm mesh.  Your worm block looks quite a bit different so perhaps this shows the evolution of these units as time went by.

 

 

Attached Thumbnails

  • Fork Assembly.jpg
  • Kenton Label.jpg
  • Worm Wheel.jpg
  • Worm.jpg

Edited by gnabgib, 23 July 2021 - 07:51 PM.

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#6 ccwemyss

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Posted 23 July 2021 - 08:10 PM

I bought one for my C8 around 1981. It was the only way to upgrade the tracking on a C8 at the time. Kencor did precision machining for aerospace, as I recall, and this was a side line. The periodic error on the gears is very small. They also made some of the earliest quartz digital drive correctors, which I also bought from them. I sold the C8 around 1988, but still have the drive corrector, which works well with my 120VAC scopes.

 

When I was working in the telescope shop, we had someone come by from Celestron, and I brought my C8 in to show him what I felt they should be offering. It had the worm gear drive, University 8x50 finder, and after market fine adjusters for altitude and azimuth. He took pictures and notes. On his way out, the shop owner said, "Oh, and another thing. Paint them black." It may have been coincidence, but the next year they came out with the Super C8, with the Byers drive, 8x50 finder, wedge with fine adjusters, and of course, it was black. That basically put Kencor out of the telescope drive business. 

 

Chip W. 


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#7 deepwoods1

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Posted 23 July 2021 - 08:31 PM

And this is why CN is the best! All this knowledge and snippets of time.


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#8 Tom Duncan

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Posted 23 July 2021 - 08:45 PM

Tom;

      I too have one of the drive bases.  They are well built and offer a huge improvement in tracking accuracy compared the the original Celestron  spur gear drive system.  I am not sure how many were made but in my 50+ years of telescope making and using yours makes the third unit I have come across.  So they SEEM pretty rare BUT look at your serial number then look at mine.  I do not know what to make of this.   My unit also has a thumb knob under the worm block to allow disengaging/ adjusting the worm mesh.  Your worm block looks quite a bit different so perhaps this shows the evolution of these units as time went by.

Mine also has the knob to allow the lifting of the worm off the driven gear, plus a spring that holds it to the gear. 

 

So is there another motor/worm gear inside the case as was described by the seller of the unit in the AM ad I linked: "It features a dual worm drive gear train with a 7 inch diameter, 359 tooth primary gear and 10rpm Hurst (Model A) motor".

 

Tom 



#9 gnabgib

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Posted 23 July 2021 - 10:02 PM

Tom;

   Only one motor.  The "dual" worm comes from the 10 rpm motor driving the main worm with a smaller worm gear set.  Your picture of the worm housing shows the smaller worm in a vertical position.  The worm drives the small wheel on the end of the main worm hence the "dual" worm drive.


Edited by gnabgib, 23 July 2021 - 10:52 PM.


#10 Tom Duncan

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Posted 23 July 2021 - 10:14 PM

Tom;

   Only one motor.  The "dual" worm comes from the 1/10 rpm motor driving the main worm with a smaller worm gear set.  Your picture of the worm housing shows the smaller worm in a vertical position.  The worm drives the small wheel on the end of the main worm hence the "dual" worm drive.

Ah, I get it, thanks for the clarification. 

 

Tom



#11 Tom Duncan

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Posted 25 July 2021 - 04:46 PM

It looks like the former owner of this mount has more parts for it, a drive corrector, special mounting plate, wedge and tripod. Not sure when I can get there to pick them up, will add more to this thread when I get them. 

 

Tom 


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#12 ccwemyss

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Posted 26 July 2021 - 09:48 PM

Well, I knew I had this stuff somewhere. Here is pretty much everything you would want to know about Kencor products. Two brochures, and the instructions for the 7500 drive corrector, including the computer printout table of corrections for atmospheric refraction:

 

https://www.cloudyni...cor-literature/

 

Here is the only image that's small enough to include in a post (go to the gallery to see the rest):

 

Kencor 81-1.jpg

 

Chip W. 


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#13 Tom Duncan

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Posted 27 July 2021 - 09:05 AM

Wow! Thanks Chip, very helpful. Amazing how I keep running into astro stuff I've never seen or heard of before, great fun.

 

In 1978 the drive base was $250, $1049 in todays dollars. We don't know how good we have it...

 

Tom


Edited by Tom Duncan, 27 July 2021 - 08:33 PM.


#14 Brianfromsyr

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Posted 14 October 2021 - 03:41 PM

Hi. I actually have that 7700 model someone posted. It is a astro camera drive.
For some reason it is also listed as Kajer Model 7700. The gears that you show are the same as what I have.
No manual came with mine.


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