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Equipment Discussions >> Classic Telescopes

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tim53
Postmaster
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Reged: 12/17/04

Loc: Highland Park, CA
Re: cave setting circles new [Re: dgreyson]
      #5564458 - 12/10/12 04:31 PM

That actually seems right. I don't know of anybody using those circles after Cave folded.

Cool, my 12.5" has the 10" circles on it. They're awesome!

-Tim.


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SteveNH
professor emeritus
*****

Reged: 07/10/11

Loc: Millbrae, CA
Re: cave setting circles new [Re: tim53]
      #5565158 - 12/10/12 11:47 PM Attachment (10 downloads)

Just for comparison, here are the circles on the Cave mount I bought in 1969 for my 8". (I know, it needs a little TLC.) These 6" ones look very much like the Magnussen circles, and are solid aluminum. They are precisely made, and work very well. I wish the RA circle rode on the worm gear though, as in Tim's. I've come to tape it to the housing during observing so it doesn't move while I'm on an object.

The RA cirlce:


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SteveNH
professor emeritus
*****

Reged: 07/10/11

Loc: Millbrae, CA
Re: cave setting circles new [Re: SteveNH]
      #5565160 - 12/10/12 11:48 PM Attachment (8 downloads)

And here is the DEC circle:

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dgreyson
professor emeritus
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Reged: 11/06/12

Loc: South Carolina
Re: cave setting circles new [Re: SteveNH]
      #5565509 - 12/11/12 08:16 AM


Is it not supposed to move in step with the polar axis when the clock motor is running? Or is it too loose and spinning? Mine have a teflon rod backed by a set screw so it can be tightened down but still be able to be adjusted against the friction holding it and then keep its new place.
May want to pull it off an have a look at that, someone may have greased it in error.


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clintwhitman
Caveman
*****

Reged: 01/01/07

Loc: CALI SoEasyACavemanCanSlewIt
Re: cave setting circles new [Re: dgreyson]
      #5565593 - 12/11/12 09:29 AM

D I read that before but after talking with Oscar back in the late 1970s he said he still sold some circles and other stuff and I guess that over road what I read.

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dgreyson
professor emeritus
*****

Reged: 11/06/12

Loc: South Carolina
Re: cave setting circles new [Re: clintwhitman]
      #5565693 - 12/11/12 10:40 AM

My guess is that Cave had bought some tooling etc. from him to make their own copies and Oscar continued making circles on his own as well.

p.s - I havent forgotten about taking some pictures for you, will get on the stick with that asap.


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chuck52
super member
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Reged: 12/03/09

Loc: Quartz Hill,California
Re: cave setting circles new [Re: dgreyson]
      #5565745 - 12/11/12 11:16 AM

I have been reading all the replies with great interest.I checked my caves setting circles. The 71' 12.5 inch and 62' 10 inch have what I assume are Magnusson circles.The 75' 10 inch and 73' 8 inch have the standard circles.Im going by the pictures posted so far.Im also assuming that back then you could buy circles direct from Magnusson or get them as an option on a new cave scope.Other than some differences in the scribed line length the two types of circles seem very similar.I must admit that up until I started reading this forum on a regular basis I was not aware of two types of circles.

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SteveNH
professor emeritus
*****

Reged: 07/10/11

Loc: Millbrae, CA
Re: cave setting circles new [Re: dgreyson]
      #5566147 - 12/11/12 03:31 PM

Quote:


Is it not supposed to move in step with the polar axis when the clock motor is running? Or is it too loose and spinning? Mine have a teflon rod backed by a set screw so it can be tightened down but still be able to be adjusted against the friction holding it and then keep its new place.



It actually does have a set screw, which I keep loose. I found that it was easiest for me to go ahead and use the RA indicator mark that's built onto the drive housing. Since my RA circle free-wheels and rides directly on the polar shaft, I let it turn while slewing to continually indicate the correct RA that my tube is pointing to. I first set it with an object and pin it down once I'm tracking - that is, once I find that object, the RA circle is taped and fixed constant at its RA reading while the shaft continues to turn at the sidereal rate, tracking the object. Then when I slew to the next object, as long as I release the RA circle and allow it to turn with the axle again, the pointer will always indicate the correct RA readings for the next parts of the sky that I point to.
... clear as ... mud.


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John Higbee
super member
*****

Reged: 07/17/12

Loc: Virginia
Re: cave setting circles new [Re: tim53]
      #5566694 - 12/11/12 10:37 PM

Tim - The declination circle could work, but the RA "ring" wouldn't. Thanks for looking...really appreciate it! John

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John Higbee
super member
*****

Reged: 07/17/12

Loc: Virginia
Re: cave setting circles new [Re: Don Hall]
      #5566699 - 12/11/12 10:39 PM

Don - sounds good to me...PM sent w/ my address. thanks, John

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chuck52
super member
*****

Reged: 12/03/09

Loc: Quartz Hill,California
Re: cave setting circles new [Re: clintwhitman]
      #5567551 - 12/12/12 01:04 PM

Hi Clint,
What color did you use to paint the '65 Cave mount? Im still wrestling with the correct color for my'62 mount.It looks brownish but when I put it in the parts cleaning tank I started seeing what looked like a black undercoat.I did not see any white specks in the black paint.


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