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Equipment Discussions >> Classic Telescopes

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actionhac
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Mr. Edmund gets a Drive
      #5469767 - 10/14/12 01:06 PM Attachment (74 downloads)

Today I'm going to install a drive on my Edmund Scientific 4"f15 refractor.
Feast your eyeballs on this:


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5469776 - 10/14/12 01:10 PM Attachment (59 downloads)

Here is the drive. Year/model doesn't make much difference, if you have a 1" Edmund mount and a 1" Edmund drive they should be compatible.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5469779 - 10/14/12 01:12 PM Attachment (39 downloads)

Specs from the drives motor. This one was made 6 (June) 1970

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5469788 - 10/14/12 01:17 PM Attachment (42 downloads)

The manual mount. Soon it will be able to compensate for the earth's rotation, automatically and hands free.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5469798 - 10/14/12 01:22 PM

I'll see you in a while. I seem to be missing a few parts like the slow-motion cam lever and a small ball-bearing, they could not have gone far.

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tim53
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5469835 - 10/14/12 01:43 PM

That's a handsome scope!

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trainsktg
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Re: Mr. Edmund gets a Drive new [Re: tim53]
      #5469842 - 10/14/12 01:48 PM

A very nice setup indeed. What keeps the legs from flying apart though?

Keith


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bremms
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Re: Mr. Edmund gets a Drive new [Re: trainsktg]
      #5469862 - 10/14/12 02:01 PM

friction with the gound?

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bremms
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Re: Mr. Edmund gets a Drive new [Re: bremms]
      #5469863 - 10/14/12 02:03 PM

I really like long refractors. Very nice.

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apfever
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Re: Mr. Edmund gets a Drive new [Re: trainsktg]
      #5469864 - 10/14/12 02:04 PM

Quote:

A very nice setup indeed. What keeps the legs from flying apart though?

Keith




The coefficient of static friction on the ground only. I'd get a chain in there.

The RA shaft is short but it should work. The bushing needs to be removed. The RA housing is machined to take the pin assembly and the drive should mount on the exposed shaft after the bushing is removed. Those drives are the same on several different Edmund shaft diameters. They have bushings that adjust for the shaft sizes.

I finally have an original lens on the way to replace the shattered flint in my 57 Edmund 4".


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: apfever]
      #5469995 - 10/14/12 03:18 PM Attachment (44 downloads)

That's great you found a lens Neil. You have a ultra cool scope, much older than mine.
I should get a safety chain although the pointed legs do not slip. Those are Astro Optical legs from my 7TE-5. I don't have any original one piece Edmund legs. I am planning on making some.
Here are the missing pieces, the slo-mo lever and the steel ball that retains it:


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5470003 - 10/14/12 03:22 PM Attachment (25 downloads)

You remove this collar from the polar shaft. The drive mounts to the newly exposed shaft and the housing where it steps down.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5470009 - 10/14/12 03:26 PM Attachment (24 downloads)

You should do some maintenance like clean/oil this worm thrust bearing and oil the motor output shaft bearings.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5470013 - 10/14/12 03:29 PM Attachment (24 downloads)

There are 2 shaft set screws down through the housing, rotate the shaft within the housing until these are exposed and then you can lock it down to the polar shaft.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5470031 - 10/14/12 03:39 PM Attachment (41 downloads)

Once the pieces are installed adjust the eccentric studs A to remove slop from the slo-mo cam. The 2 thumb screws B are to adjust the slip clutch. Balance the optical tube in it's saddle and then tighten/loosen the clutch till it just holds without slipping.
You are ready now for hands free high power tracking. And extended observation at the eye-piece so your brain has time to process what it is seeing.
Robert


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M Schnittker
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5470038 - 10/14/12 03:43 PM

Very nice! I built my first telescope in 1969 using an A Jaegers mounted 4 1/8" objective ($69) with Jaegers aluminum tube and focuser on an Edmunds mount ($49?), had a Unitron 40mm finder scope. The had one eyepiece, a Brandon Vernonscope 16mm and a Dakin 2.4x Barlow, I think they were something like $24 and $29 each. I bought the mount version that mounts on a pipe intended for reflectors vice the tripod equipped version thinking it would be more stable, I found a heavy 3" x 5 foot long pipe for it at a junk yard. I still have that scope and mount, great lens. Now I'd love to find the parts to convert my pipe mounted mount to a tripod rig. May end up making the parts myself. Couldn't afford a clock drive at the time, it was 1969 and part time jobs brought in $35 in a good month so it took a while to save up for the parts I did buy. I recall the clock drive was close to $40, something like that. I now have 3 of the 1" shaft Edmund mounts which I use for various scopes and all have Edmund drives, their ID plates have various dates all in the 1960's, there are some differences in the design over the years, can provide photos if anybody is interested. As I get older I find it very fun to acquire items like the Edmund clock drive that I lusted for in my youth but couldn't afford, a circle completed. I really like the old Edmund mounts, would like one of the 1.5" versions they sold with their 8" reflector, THAT was a scope I really lusted for! Seemed so huge then.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: M Schnittker]
      #5470105 - 10/14/12 04:18 PM

I still have my first Edmund catalog from 1969. I could only afford chipped lenses and prisms, I wasn't even a teenager yet. I'm making up for it now though.
Actually I bought one of these 4 inchers back in the 70's and have had a few since.
Now I'm sort of doing a mock-up here with this one, it really needs a full restoration but I assembled it and again refreshing my memory over the superb lens. I've had this one a few years but have not used it at all for a while.

It would be great to see any pictures you might have. I'd like to see an older style drive, before Edmund added the slo-mo lever assy., don't know if you have one like that.

Robert


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amicus sidera
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5470246 - 10/14/12 05:43 PM

Excellent thread, Robert, and a fine photo-tutorial!

I notice that the motor shown doesn't appear to have an oil port in the base to allow for lubricating the gearbox; the reduction gears are the trouble spot on these motors, as the speed reduction needed is so great compared to a 1 rpm, or even 1/10 rpm motor of similar design. If you're interested, there's a CN thread detailing how to go about getting into the gearbox on these old synchronous motors here... properly lubricated, it should last for decades.

Have fun with that fine refractor!


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: amicus sidera]
      #5470296 - 10/14/12 06:05 PM Attachment (39 downloads)

Thanks for the link Fred.
This one does not have a lube hole for the gear box. Amazing isn't it we really made some nice stuff didn't we. Almost 1/2 century old and it is as quiet as a church mouse. I didn't even think about all those gears in there.

I need to make a correction. Previous photos show the drive above a tripod leg, that is a error, the drive should be between two legs, thusly:


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starman876
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5470439 - 10/14/12 08:07 PM

I used to have one of these mounts with that drive. It worked very well. Very nice set up.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: starman876]
      #5470927 - 10/15/12 02:04 AM Attachment (30 downloads)

I have a few extra pictures you might like....
This 23mm finder is small but perfect in every way. Beautifully made. Helical focus on the objective end and also focus for the retical.


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5470936 - 10/15/12 02:11 AM Attachment (28 downloads)

With a little tuning this focuser provides excellent performance.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5470940 - 10/15/12 02:15 AM Attachment (25 downloads)

Anyone know who made these lenses for Edmund?
Later on Edmund made lenses in-house.


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trainsktg
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5470947 - 10/15/12 02:19 AM

I have the same finder on my 4.25" reflector...its a very nicely designed unit.

Keith


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5470951 - 10/15/12 02:28 AM Attachment (23 downloads)

The only documented information on the source I've found is a 1956 Edmund Scientific Corp. ad stating:

"We found a Japanese optical engineer who designed some excellent astronomical objectives. We place orders with him. He then has these made, testing each one for quality".



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mikey cee
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5471273 - 10/15/12 10:56 AM

Robert has this lens ever been apart before? I ask because if the crown is flipped then both arrows point skyward and the "12's" are lined up too. I always thought that arrows pointed to each other but I've since seen some claim both should point in the same direction. Mike

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: mikey cee]
      #5471316 - 10/15/12 11:16 AM Attachment (22 downloads)

Hi Mike.
Edmund sure does stamp a ton of information on the edges, the fine print makes it clearer.
The dark arrows are rotation index marks and point at each other.
This one may be readable:
I guess it isn't. The fine print reads:

FLINT ELEMENT FACES EYE ARROWS POINT TOGETHER (bottom lens in photo)

CROWN ELEMENT FACES OBJECT ARROWS POINT TOGETHER

The faint arrows face each other but are not indexing and the dark (blue 12) arrows are the index marks.


Edited by actionhac (10/15/12 11:32 AM)


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5471363 - 10/15/12 11:38 AM Attachment (21 downloads)

It's quite a feat loading the elements into the cell.
I hang the whole optical tube on the edge of a open door by a finder ring hooked over the top, cell facing the floor and raise the elements into the cell followed by the retaining ring.
The cell cannot be attached to the tube with the lens installed.
I don't have a good picture of the cell only this one:


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mikey cee
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5471949 - 10/15/12 05:36 PM

Well like I said I've always thought that arrows pointed at each other. I guess some do and some don't....'spose I'll just shut up and go with the flow as the flow dictates. Mike

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: mikey cee]
      #5471990 - 10/15/12 05:57 PM

I scratch my head a little every time I read the markings and look at the arrows. It is confusing, or more of a "don't want to do it twice" project.
When removing and installing the elements a very high risk of getting a element cocked sideways in the retainer ring threads exists. If that happens you can end up with a clam chip.
I don't like doing it unless I must. I have my Sam Brown "All About Telescopes" I refer to just to make sure on the arrows.
Otherwise I like the cell, its very light and the focuser+finder is light too so the scope balances near the middle of the tube.

Robert


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Retentive
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5472378 - 10/15/12 10:07 PM

Awesome telescope. I remember just staring at the catalogue wishing I could have one!

Phil


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: Retentive]
      #5850900 - 05/09/13 08:45 PM Attachment (11 downloads)

The past few days I've been working on the 4" Edmund.
I made a wood shelf to replace the normal tin eyepiece tray. I am surprised how much it stiffened up the tripod.


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5850907 - 05/09/13 08:50 PM Attachment (13 downloads)

I changed to a earlier head to get the channel saddle and a better seating for the tube rings.
I painted a few parts on this head back when gray wrinkle was still available. As you can see it has a green tint, I over heated the paint when I dried it in the oven.


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5850915 - 05/09/13 08:53 PM Attachment (13 downloads)

This is a good arrangement, the earlier model channel with rings. If you want to use rings. I do right now.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5850926 - 05/09/13 09:01 PM Attachment (12 downloads)

The shelf is great. Stiffens things up and glowy likes it too. He's getting old and wants a flat surface to stand on. No more climbing tubes at 65 million years of age.
As you can see I got a little carried away adding a light, I'll probably remove it, maybe, we will see. I guess I will see! I might like it !


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5850929 - 05/09/13 09:03 PM Attachment (16 downloads)

I do like this level!

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Chassetter
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5850950 - 05/09/13 09:23 PM

Yes, but watch out, Glowy may have too much time on his hand now that you've retired hime...he's eyeing that RKE with dinner on his mind! :P Wonderful setup by the way.

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ngc2289
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5851312 - 05/10/13 03:11 AM

A 1" Edmunds drive will also work on a 1" Jaegers mount. I had the 1" Jaegers mount, and put an Edmund drive on it.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: ngc2289]
      #5851822 - 05/10/13 11:21 AM

My first Edmund telescope years ago had the opposite, a Jaegers drive on a 1" Edmund and it did fit fine.
I sure liked the Jaegers 6" cast aluminum setting circles I had on that scope.

Robert


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5851862 - 05/10/13 11:46 AM Attachment (17 downloads)

Anyone ever wonder what the 3 holes in the worm gear are for? as near as I can tell its for this kit:

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5851865 - 05/10/13 11:49 AM Attachment (18 downloads)

Here it is mounted to the gear. I have no part number and cannot find it in any Edmund catalog.

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DAVIDG
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5851885 - 05/10/13 11:59 AM

Do you know what that kit is for ?
- Dave


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: DAVIDG]
      #5851894 - 05/10/13 12:09 PM

To make it possible for the RA circle to move with the clock rather than being fixed to the mount. The Plexiglas pointer also is fixed to the polar shaft.
I'm hoping you know the benefits of doing this way Dave!

Robert


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DAVIDG
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5851961 - 05/10/13 12:56 PM

Quote:

To make it possible for the RA circle to move with the clock rather than being fixed to the mount. The Plexiglas pointer also is fixed to the polar shaft.
I'm hoping you know the benefits of doing this way Dave!

Robert




Sure do ! Just wondering how many how others know about this and why it is a benefit. I find it interesting that only few classic scope had this feature. I also wonder how many classic scope owner even know how to use setting circles ? I have never seen this kit as well or Edmund scope that had one attached.

- Dave


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chuck52
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Re: Mr. Edmund gets a Drive new [Re: DAVIDG]
      #5851999 - 05/10/13 01:14 PM

I could use two of those kits.Looks like the parts could be made without too much difficulty.The installed kit does show up in some Sam Brown illustrations in his books.

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tim53
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Re: Mr. Edmund gets a Drive new [Re: chuck52]
      #5852055 - 05/10/13 01:37 PM

My Optical Craftsmen mounts have driven RA circles.

Thankfully, so does the 12.5" Cave Model D Transportable Observatory (complete with 10" circles!!), though my other Cave mounts don't.

I don't think the Meade Newtonians ever had driven RA circles either.

Wonder why not? Granted, they're harder to make, but ever use one that's not driven? What a pain!

-Tim.


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rdandrea
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Re: Mr. Edmund gets a Drive new [Re: tim53]
      #5852063 - 05/10/13 01:43 PM

Quote:

I don't think the Meade Newtonians ever had driven RA circles either




I think the RA circle on my 645 turns with the clock. It's loosely friction fit so that you can reset it.


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terraclarke
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Re: Mr. Edmund gets a Drive new [Re: rdandrea]
      #5852086 - 05/10/13 02:00 PM

Very interesting thread Robert. I have really enjoyed reading about your restoration of the trusty Edmund 4 inch refractor. Very cool. I love the old mount. I hope I can find mine now. Since things of late are re-emerging from the blackhole they disappeared into years ago, I have high hopes.

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DAVIDG
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Re: Mr. Edmund gets a Drive new [Re: terraclarke]
      #5852119 - 05/10/13 02:17 PM

Robert,
Maybe you can measure up the hubs and post details so other i.e. me can reproduce it ? I'll have to check my copies of All About Telescopes and see what I can find out about the kit.
By the way how are you powering the drive ? I use an inexpensive DC/AC inverter and 12 volt "battery boost" to provide the DC power for the inverter. I dug inside the inverter an adjust the output frequency so it makes these drive track at sidereal rate vs solar rate. The inverter and battery boost makes for a nice compact package and I don't have to drag out 30' of extension cord.

- Dave


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john gabriel
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Re: Mr. Edmund gets a Drive new [Re: starman876]
      #5852141 - 05/10/13 02:33 PM

Hi Robert. Thank you for posting this interesting material! - I'm just catching up, and I have a question about the drive. I have the same one on Edmund's 6" newt, and I get a good deal of slop on the polar axis.

I initially tried what you suggested on first page of this thread - "adjust the eccentric studs A to remove slop from the slo-mo cam". I squeezed the studs together fairly tightly on the cam and cinched down their cap screws, but the cam pin itelf seems to have quite a lot of slop in the housing it rides in.

I do not want to machine a whole new cam pin to fit more closely in the housing, and shimming the housing does not seem very practical either. That seems to leave boring out the housing and fitting a sleeve with closer tolerance on the pin. What's best? Any other ideas on this? Thank you!
John


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DAVIDG
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Re: Mr. Edmund gets a Drive new [Re: john gabriel]
      #5852167 - 05/10/13 02:45 PM

Check that you have the single ball bearing still in place that puts pressure on the cam. It is located under the metal strip on the side of the drive. It sounds like it is missing or might have a flat spot worn in it.

- Dave



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john gabriel
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Re: Mr. Edmund gets a Drive new [Re: DAVIDG]
      #5852310 - 05/10/13 04:46 PM

Thank you Dave. I did have that apart for cleaning, inspection, and lube when I rescued the scope. I will check again, but the ball bearing looked fine / unworn at the time. The wiggle in the cam pin seems to be as much at the lower end of the housing as at the upper end where the ball is, but I will recheck the ball for wear anyway.

I have no idea if the timing adjust was actually used by prior, original, owner, but in other areas it's apparent that he did not lube the mount. I obviously need to take it apart again and inspect the pin tolerance in the housing more closely.

I just wondered if others who use these had noticed the lash as common / design issue and what, if anything, people had done to reduce the problem


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tim53
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Re: Mr. Edmund gets a Drive new [Re: rdandrea]
      #5852333 - 05/10/13 05:09 PM

Quote:

Quote:

I don't think the Meade Newtonians ever had driven RA circles either




I think the RA circle on my 645 turns with the clock. It's loosely friction fit so that you can reset it.




The pointers are on the dec casting, so they're driven, but the RA circle is on the RA casting and doesn't move except when you turn it manually. If it were driven, it would move with the pointers. Since it doesn't, you have to reset the circle before you leave one object and move to the new target. A driven RA circle only needs setting once at the beginning of an observing run.

-Tim.


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rdandrea
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Re: Mr. Edmund gets a Drive new [Re: tim53]
      #5852343 - 05/10/13 05:12 PM

Quote:

the RA circle is on the RA casting and doesn't move except when you turn it manually




Tim, I'll go out to the garage to check it out one of these days.


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john gabriel
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Re: Mr. Edmund gets a Drive new [Re: rdandrea]
      #5852381 - 05/10/13 05:36 PM

With this Edmund drive, I put a nice RA circle at the outer end of the polar axis, on the inner clutch plate no less, and will be mounting the pointers (vernier index) to the drive gear. This allows the RA to remain constant while tracking / viewing and then change when slewing to another object.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: john gabriel]
      #5852696 - 05/10/13 08:32 PM Attachment (11 downloads)

Let me know if this is readable. If not I can send by email.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5852704 - 05/10/13 08:41 PM

Dave I have a inverter 12VDC to 115V I use, and most of the time I plug into house current from where I observe on my driveway. Its not the best situation observing from a giant slab of concrete heat sink but otherwise I have hardly any level lawn. I really want to do something about this soon.
John have you checked the gear lash for play? if you have the eccentric slo-motion pin pinched without play try taking up any play in the gear lash. It doesn't seem possible the slo-motion shaft would be worn in the housing since it gets used so little but it should be tight in the housing. Your idea of sleeving the housing would be what I would do before making a new shaft with eccentric pin. If it isn't too bad you can have the shaft plated to increase its diameter.

Robert


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DAVIDG
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5852910 - 05/10/13 10:38 PM

Robert,
Many thanks for posting the design of the setting circle adapter. I found a few sentences and a drawing of it in All About Telescopes as well. I'll see if I can machine the parts up for my mount.

- Dave


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: DAVIDG]
      #5854298 - 05/11/13 07:34 PM Attachment (5 downloads)

I was rooting around in the Edscorp box again today.
This is a brand new 1/4" focal length Ramsden eyepiece. Instructions is Rev. 6/75.


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5854305 - 05/11/13 07:43 PM Attachment (5 downloads)

Here are a pair of Ramsden, 1/4" focal length and 1/2"fl.
The 1/4" has a problem. I will need to take it apart and look for a flipped element. The tiny little elements in a short fl eyepiece is a very rewarding challenge to take apart and reassemble and not have a coronary.
Notice these do not have the focal length stamped on top, older or newer, anyone know?


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5854309 - 05/11/13 07:50 PM Attachment (9 downloads)

Edmund eyepieces are different. The whole eyepiece is one machined piece of aluminum and the only removable part is the lens retainer inside as shown on the left. You unscrew it and that is it to get the guts out. When you screw the retainer back in you do it ever so carefully by hand just to the point when you can no longer hear any rattle from the elements.

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amicus sidera
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5854675 - 05/12/13 12:24 AM

Quote:

Its not the best situation observing from a giant slab of concrete heat sink but otherwise I have hardly any level lawn.




Robert, you might find that soaking that concrete pad with water just before sunset cools it off pretty quick, and really improves ground seeing. I sometimes observe over concrete, and give it a good soaking with a hose once the pad is in the shade just prior to dusk; it's a very effective way to cool off such a surface rapidly.

Following your posts here with much interest; excellent work!

Fred


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: amicus sidera]
      #5854713 - 05/12/13 01:13 AM

Thats not a bad idea Fred! I'm going to try it. It will also reduce the pollen and dust around my scope wetting down the slab.
I can move to the lawn, its not difficult leveling a tripod. It is a royal pain though to level a pier so I'm just a creature of habit and stick to the slab.
I'll try soaking it down. Its not something I'll need to do everytime, only when its a very hot day and I predict a colder night.

Robert


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amicus sidera
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5855065 - 05/12/13 09:17 AM

Hope it works well for you, Robert; the only caveat being that this method is naturally less effective in humid conditions, as it relies upon evaporation to accomplish cooling.

Fred


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john gabriel
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5856358 - 05/12/13 09:14 PM

Robert, thank you for your suggestions sources of lash in the polar axis lash. I had it apart again yesterday, and:
1. The lash at thrust bearing, worm, and drive gear are zero - that's been adjusted pretty closely.
2. There is no visible wear on ball bearing, and leaf spring supporting the cam pin is plenty stiff.
3. Lash at the outer end of cam pin inside of its housing seems to be half the problem, even though as you say this should have little wear. It does have some wiggle, and I have those two posts on either side of the cam pin as snug against the cam as I can get them.
4. The other half of the lash problem is obviously coming from slop in the fit of polar axis in its casting. The teflon sleeve on the lower end of polar axis is cracked and probably should be replaced with a "new" one or some shim / sleeve of same thickness

I see no real advantage to the minimal "slo-mo" control. Seems it would be better if the tangent and its worm support were solidly fixed to the RA housing without the cam pin arrangement entrained. In any case, I've found I can live with the lash, as long as I remember to push the scope "eastward" to the target I want to track.


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: john gabriel]
      #5856673 - 05/13/13 12:34 AM

Look at this drive and the added screw to tighten the slo-mo shaft housing:
http://www.ebay.com/itm/Edmund-Scientific-Vintage-Worm-Gear-Electric-Clock-Dr...
If your play is 1/2 the polar shaft bushing and 1/2 the slo-mo housing, at least you have identified the source of the problem and can live with it the way it is. The older mounts used bronze bushings and you could knurl the bushing OD and when you put it back in the housing the bushing ID would tighten. Not much you can do with the Teflon. I suppose you could try hand knurling the outside of the bushing.
The added screw above really isn't a bad idea, to tighten up the play in the slo-mo shaft housing. I'd rather not drill a hole in my housing though. Unless I'm mis understanding the real intention of the screw, it may be a lock I guess.

Robert


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john gabriel
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5859070 - 05/14/13 01:45 AM

Thank you, Robert. If I want that thing tight, I'm gonna have to tinker with it some. It seems that a good fit on polar shaft would have been better than the teflon thing, but as they say, "It is what it is". It's a good solid mount, and it does track well if I come into the target object from the right direction to take up the lash when starting to track.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: john gabriel]
      #5861362 - 05/15/13 01:58 AM Attachment (9 downloads)

Pacific Instruments:
http://geogdata.csun.edu/~voltaire/classics/pacinst/pacinst.pdf
made a great 1" drive. And it will work on a Edmund 1" mount.
Adaptable to most telescopes. Easy to work on and also sports a driven setting circle.
You see these for sale from time to time. Pacific Instruments is stamped into the drive so most of the time the seller knows who made it and will advertise it as a Pacific Instruments clock drive.
Here I have one on a larger 1.5" Edmund mount. Edmund reduced the polar shaft to 1" for the drive.


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john gabriel
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5862801 - 05/15/13 06:16 PM

Hi Robert - not sure what you imply there - is it out of production meaning I have to find it used? That's a nice looking set of circles going with it, especially if still being sold new.
John

I see from a little looking and reading that these are no longer being made - at least those by Pacific Instruments.

Edited by john gabriel (05/15/13 06:24 PM)


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: john gabriel]
      #5862879 - 05/15/13 06:36 PM Attachment (4 downloads)

Hi John.
I thought I would post a picture of something besides a Edmund drive to show everyone that other drives will fit.
Pacific Instruments is no longer in business but its good gear and quite common on the used market. I particularly like the 1" mount also.
Here is another Pacific Instruments drive on a Cave mounting. Someone spent some time to get this to work since it required a pretty fancy adapter attached to the bottom of the polar shaft housing.


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wfj
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5863223 - 05/15/13 09:28 PM Attachment (7 downloads)

Robert,

I've also seen Meade drives on Astrola's. Here's a Jaegers mount with an Edmund drive.


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: wfj]
      #5863282 - 05/15/13 09:55 PM

I love the red knobs on Jaegers stuff!
Your drive has the rare automatic RA circle kit installed we were just talking about earlier.

Robert


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5863469 - 05/15/13 11:20 PM

I decided to take a closer look in the catalogs for the driven RA circle kit.
It's in the catalog! just no picture, so I failed to see it!
Well right there under my nose, catalog #671 (1966) it is a new item for this catalog:

"NEW! CLOCK-DRIVEN RIGHT ASCENSION CIRCLE Mounts directly on clock drives to provide sidereal time and eliminate calculation of star positions. Stays true to moving star pattern without your having to correct it. Black phenolic circle with pointer and mounting hardware. No. 60,569 $9.00 Ppd.".

Robert


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5863558 - 05/16/13 12:11 AM Attachment (7 downloads)

Here is the far-out cover.

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wfj
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5865102 - 05/16/13 04:38 PM

Quote:


Your drive has the rare automatic RA circle kit installed we were just talking about earlier.



Hmm. You're right Robert - its right in front of me. I guess I'd better pay more attention in class

Now I guess I'd better find those setting circles and pointer ... where to look in the 40+ year pile of astro stuff ....

Thanks for noticing!


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actionhac
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Re: Mr. Edmund gets a Drive new [Re: wfj]
      #5865746 - 05/16/13 08:03 PM Attachment (4 downloads)

On the outside it appears to be a standard Edmund prism diagonal....

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5865761 - 05/16/13 08:10 PM Attachment (4 downloads)

It has a built in barlow!

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5886222 - 05/26/13 09:13 PM Attachment (1 downloads)

Look at these Astro Optical tripod legs and how beat up they are:

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5886225 - 05/26/13 09:15 PM Attachment (1 downloads)

I cleaned them with some thinner and stained and then applied a coat of clear lacquer with a rag.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5886229 - 05/26/13 09:17 PM Attachment (1 downloads)

Perfect color match just in case your Astro Optical Tasco 7TE 7TE-5 etc. is in need of a touch up.

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actionhac
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Re: Mr. Edmund gets a Drive new [Re: actionhac]
      #5886231 - 05/26/13 09:19 PM Attachment (5 downloads)

Here it is. It was on a shelf in my shop.

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