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Equipment Discussions >> Classic Telescopes

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TOM KIEHL
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? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ?
      #5940053 - 06/25/13 04:10 PM Attachment (108 downloads)

I Bought this telescope over the weekend and was told that Edmunds Scientific never produced a cassegrain telescope.
Please look at the images as i am looking for information regarding this telescope. ??


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TOM KIEHL
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Reged: 11/17/12

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940054 - 06/25/13 04:11 PM Attachment (86 downloads)

#2

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TOM KIEHL
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Reged: 11/17/12

Loc: N.E. Ohio
Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940056 - 06/25/13 04:12 PM Attachment (56 downloads)

#3

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TOM KIEHL
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Reged: 11/17/12

Loc: N.E. Ohio
Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940060 - 06/25/13 04:13 PM Attachment (43 downloads)

#4

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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940064 - 06/25/13 04:14 PM Attachment (50 downloads)

#5

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TOM KIEHL
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Reged: 11/17/12

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940065 - 06/25/13 04:14 PM Attachment (45 downloads)

#6

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TOM KIEHL
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Reged: 11/17/12

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940066 - 06/25/13 04:15 PM Attachment (55 downloads)

#7

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TOM KIEHL
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Reged: 11/17/12

Loc: N.E. Ohio
Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940067 - 06/25/13 04:16 PM Attachment (54 downloads)

#8

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starman876
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940069 - 06/25/13 04:18 PM

could be an early coulter. I have one that looks a lot like that

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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940072 - 06/25/13 04:21 PM Attachment (35 downloads)

#9 Scribed in mirror " BLC LSTEINLE " or possibly " BLC L.STEINEL "

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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940079 - 06/25/13 04:23 PM Attachment (34 downloads)

#10

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TOM KIEHL
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Reged: 11/17/12

Loc: N.E. Ohio
Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940081 - 06/25/13 04:24 PM Attachment (34 downloads)

#11

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TOM KIEHL
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Reged: 11/17/12

Loc: N.E. Ohio
Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940083 - 06/25/13 04:24 PM Attachment (29 downloads)

#12

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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940084 - 06/25/13 04:25 PM Attachment (25 downloads)

#13

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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940089 - 06/25/13 04:27 PM Attachment (28 downloads)

#14

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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940092 - 06/25/13 04:27 PM Attachment (23 downloads)

#15

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TOM KIEHL
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Reged: 11/17/12

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940093 - 06/25/13 04:28 PM Attachment (24 downloads)

#16

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TOM KIEHL
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Reged: 11/17/12

Loc: N.E. Ohio
Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940094 - 06/25/13 04:28 PM Attachment (27 downloads)

#17

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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940097 - 06/25/13 04:30 PM Attachment (34 downloads)

#18

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TOM KIEHL
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Loc: N.E. Ohio
Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940100 - 06/25/13 04:31 PM Attachment (43 downloads)

#19

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TOM KIEHL
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Reged: 11/17/12

Loc: N.E. Ohio
Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940103 - 06/25/13 04:33 PM Attachment (24 downloads)

#20 Ttipod spreader hardware

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DAVIDG
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940125 - 06/25/13 04:45 PM

The mount and finder are Edumnd. The mirror cell and spider are Novak. I have the exact same mirror cell and I'm building a 6" f/20 Dall Kirkham with it.
The primary is made from an old style Corning "Slope Sided" Pyrex blank which was popular in the 50's thru the 70's. The owner's name in the back and was most likely inscriped when it was coated. The optics are most likely a Dall Kirkham configuration and could have been made by Coulter or 3B Optical. You need the exact radius on the primary and that of the secondary to calculate the spacing needed for the secondary to secondary distance. You'll also need a baffle tube in the primary or the image will be washed out from sky light.

- Dave


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starman876
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940213 - 06/25/13 05:50 PM

wow. that was how mine came. The Edmunds mount with a 6" cassegrain riding on top. Just because the mount says Edmund does not make the optics Edmund. Edmund sold a lot of mounts.

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starman876
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: starman876]
      #5940218 - 06/25/13 05:53 PM

And that center brace, boy was that an accident looking for a place to happen. Going down memory lane here

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starman876
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5940220 - 06/25/13 05:55 PM

Dave

they were originally F15. Do you have a different secondary?


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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: starman876]
      #5940266 - 06/25/13 06:40 PM

What about the focuser?,,,, Edmunds maybe?,, IF Edmunds,why did Edmunds make a focuser for a cassegrain telescope if they did not sell cassegrain's????????

Edited by TOM KIEHL (06/25/13 06:46 PM)


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starman876
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940324 - 06/25/13 07:20 PM

People bought the optics and then assembled the OTA typical ATM. The focuser looks more like a classic jaegers. Most likely a refractor focuser which is what everyone used back then for a cassegrain/

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actionhac
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940332 - 06/25/13 07:22 PM Attachment (27 downloads)

Here are both refractor and Newtonian Edmund focusers. Look the same as yours? the black knobs are correct the brown knobs I'm not sure (probably radio knobs). And I think Jaegers were the same. The mounting flange on the refractor focuser came in 3 sizes and even more sizes from Jaegers if I remember right. Except the focuser tube looks different on yours.

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amicus sidera
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: actionhac]
      #5940347 - 06/25/13 07:31 PM

Could be an Edmund refractor focuser, as they did use that style of knob (Davies Mfg. made them), and if I recall correctly they had one in that flange style circa 1960's. As David noted, the mount and legs are pure Edmund, finder and its rings also, but the optics... no.

Looks to me like L. Steinl was an ATMer intent on putting assembling a nice compound scope with purchased parts. Depending on the quality of the optics, you might have quite a scope there, Tom.

Fred


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DAVIDG
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: amicus sidera]
      #5940404 - 06/25/13 08:13 PM Attachment (17 downloads)

That is also a Novak focuser. Here is a picture of the 6" f20 that I'm building now with the same Novak cassegrain mirror cell that fit 6.75" ID tube and the Novak 1.25" focuser. Here is a link to Novak's catalog, look on page 19 for their cassegrain mirror cells and focuser. http://geogdata.csun.edu/~voltaire/classics/novak/Novak_90_91_Catalog.pdf

- Dave



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DAVIDG
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5940434 - 06/25/13 08:31 PM

This scope looks to be based on what is described in Ken Novak's book "Cassegrain Notes". Here is a link to it.
http://bobmay.astronomy.net/CassNotes/#Cass

- Dave


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Dave M
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5940459 - 06/25/13 08:50 PM

Dave, i`m curious, is there any purpose to the cross lines etched across the back of that secondary mirror ?

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DAVIDG
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: Dave M]
      #5940497 - 06/25/13 09:20 PM

Quote:

Dave, i`m curious, is there any purpose to the cross lines etched across the back of that secondary mirror ?




Dave,
If the optics are Dall Kirkham type, then the secondary is supoose to be spherical so it has no optical axis. So what can be done is that the secondaries are cored from a much larger convex disk that has been ground, polished and figured to the correct radius and spherically figured. So I'm guessing that cross hairs might be alignment marks on were to center the coring bit to cut out the smaller disk from the larger one.

- Dave


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DAVIDG
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: starman876]
      #5940519 - 06/25/13 09:30 PM

Quote:

Dave

they were originally F15. Do you have a different secondary?



MY set of optics didn't come with any spacing information or radii on the mirrors. I measured the primary radius as 46.50" directly by using a Foucault knife edge test and the secondary was 13.44" via my spherometer. So with a 17.83" seperation between the primary and secondary, that result in back focal length of 10.25" and a focal length of 120". That all fits very nicely for typical an F/20 system.

- Dave


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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5940538 - 06/25/13 09:46 PM

Quote:

This scope looks to be based on what is described in Ken Novak's book "Cassegrain Notes". Here is a link to it.
http://bobmay.astronomy.net/CassNotes/#Cass
- Dave


Thanks David, that was a great piece by Mr. Novak

Edited by TOM KIEHL (06/25/13 09:52 PM)


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Dave M
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5940560 - 06/25/13 10:09 PM

Thanks! Dave, that makes perfect sense..

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Rich (RLTYS)Moderator
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5940934 - 06/26/13 06:21 AM

Tom, interesting telescope, let us know how it works.

Rich (RLTYS)


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Dave M
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: Rich (RLTYS)]
      #5941265 - 06/26/13 11:12 AM

Novak is no longer in business right

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Glen A W
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Reged: 07/04/08

Loc: USA
Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5941652 - 06/26/13 03:51 PM

Must not have been coated last in the glory days. The sticker does not have the famous 50s-60s panchro logo on it like so many I've seen. Looks like a beautiful scope, in the making, to me. GW

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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: Glen A W]
      #5941873 - 06/26/13 06:20 PM

Yes Glen, the past owner never looked through it,when he got it he said it was SILVERED ,and it was tarnished BLACK,and could not see a image at all. so he sent the mirrors out and had them coated and got them back, and thats as far as he went with it, 45 yrs. ago..

Edited by TOM KIEHL (06/26/13 06:22 PM)


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starman876
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5941895 - 06/26/13 06:28 PM

Gee that guy sounds like one of us 45 years ago

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Dave M
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: starman876]
      #5942138 - 06/26/13 09:10 PM

Quote:

Gee that guy sounds like one of us 45 years ago



You was around that long ago


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starman876
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: Dave M]
      #5942142 - 06/26/13 09:12 PM

I was in my twenties then

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starman876
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: starman876]
      #5942146 - 06/26/13 09:13 PM

If I find everything for that 6" cassegrain I will post a pic. I bought it from the guy who made it in 1978. Looks like Toms, but it in a aluminum tube. Came with a 16X50 finder. No idea where that went.

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Dave M
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: starman876]
      #5942169 - 06/26/13 09:28 PM

Tom`s is also a aluminum tube..

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DAVIDG
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: starman876]
      #5942174 - 06/26/13 09:32 PM Attachment (17 downloads)

Tom,
One of the possible reasons why the former owner most likely couldn't get an image was that he didn't have a baffle tube in the primary. Without the baffle tube the image is flooded with sky light.
My secondary is uncoated so the image is dim and I was playing around with it last night and it was very difficult to see an image because the image was swamped with sky flooding since I didn't have baffle tube as well. I calculated I need a 1.5" diameter by 8-5/8" piece of tube for the baffle. I dug around my labs at work and I didn't find anything but a quick search on the 'Net uncovered that Stables sells 1.5" x 15" mailing tubes for $1.99. So after work I stopped off at the local Stables and bought one. So over the next few days I'll make a mounting flange to mount to the inside of the mirror cell, give it a couple of coats of polyurethane to seal it and spray it flat black.

- Dave


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TOM KIEHL
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Reged: 11/17/12

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5942352 - 06/26/13 11:56 PM

Quote:

This scope looks to be based on what is described in Ken Novak's book "Cassegrain Notes". Here is a link to it.
http://bobmay.astronomy.net/CassNotes/#Cass

- Dave


David, I have a question,To the best of your knowledge, Did Ken Novak ever sell complete 6" cassegrain OTA'S ? The reason I ask is that after reading all of " Ken Novak's Cassegrain Notes" , and seeing all the drawings and pictures, included in those notes,they resemble my scope to a "T"..less the Edmunds finder. Maybe a kit by Novak , for sale that the buyer could assemable ? .....Can anyone shed some light on what the scribing's on the back of the mirror might mean? 1st. the word "MIRROR" 2nd. "BLC" and 3rd. "LSTEINLE or possibly L.STEINLE" could L.STEINLE be a mirror grinder that worked for Novak ?

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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: starman876]
      #5942384 - 06/27/13 12:54 AM

Quote:

If I find everything for that 6" cassegrain I will post a pic. I bought it from the guy who made it in 1978. Looks like Toms, but it in a aluminum tube. Came with a 16X50 finder. No idea where that went.


Johann, What if, your scope and my scope are TWINS ?,,,Then what is the odds that two different ATMer's made the same scope? That is why I think that Ken Novak sold a KIT or sold an OTA..... My tube is Aluminun also...

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Blake Andrews
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5942387 - 06/27/13 12:56 AM

Regarding the finderscope, I'm pretty sure that it was manufactured in the early to mid-1970s. JTII used that Oval silver with red lettering sticker in 1974.

Looks like a fun project.

Cheers!
Blake


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amicus sidera
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: Blake Andrews]
      #5942730 - 06/27/13 09:24 AM

Took a look at Novak's advertisements in back issues of Sky & Telescope... in April of 1981 the copy stated that he was offering a "new booklet on Cassegrain telescopes", as well as "low-cost convertible systems for dual Newtonian-Cassegrain telescopes". Other ads that I looked at mentioned that he sold mirrors (unspecified as to type), as well as secondary holders and baffles for Cassegrain telescopes.

By "systems" one could infer that he was selling complete optical sets; anyone have an early-1980's Novak catalog for confirmation?

Fred


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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: amicus sidera]
      #5942755 - 06/27/13 09:36 AM

A HA, Thanks Fred, I thought so, Maybe were on to something here....Hope Johann can find his parts to his Cass. and post pictures so we can compare .

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: amicus sidera]
      #5942796 - 06/27/13 09:58 AM

As far as I know Novak never sold Cassegrain optics or any type of telescope kits to assemble one. He did sell newtonian mirrors and secondary but I bet they were from Coulter. I have Sky and Tels back into 40's and the only companies that had ads for Cassegrain optics were Coulter, 3B and Mars Optical. Mars turned into 3B. Novak Cass parts were being designed for mostly Coulter Cass optics. As a kid a had a couple of Novak catalogs and they never mentioned a Cassegrain telescope kit. Novak's "Cassegrain Notes" was first published by him in the early 70's, I believe, which is when Coulter started to sell cassegrain mirror sets.
Since your primary mirror is made from a slope sided Corning blank, it was most likely made in the 60's. In the 70's most companies selling telescope mirrors were making them from United Lens blanks were have squared sides and both faces of the disk were the same diameter. So my guess it that it is either a homemade set of optics or 3B made them.

- Dave


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5942827 - 06/27/13 10:20 AM

The first mention of Cassegrain Notes in a Novak S&T advertisement is in the April 1978 issue, page 73 (Newtonian Notes predates this by several years), but his ads from at least 1975 mention Cassegrain baffle tubes and mirror mounts... as you said, Dave, he almost certainly wasn't producing mirror sets, but reselling those made by others.

Fred

e.t.a.: just on a side note, the feeling of nostalgia I get from going through old issues of S&T can be quite strong at times; ah, for a simpler era... or at least, one in which I'm in my early twenties again!


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5942840 - 06/27/13 10:28 AM

Not that it means much but didnt you tell me the guy you bought the scope from bought it from a camera shop in Houston 30-some years ago.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: Dave M]
      #5943094 - 06/27/13 01:14 PM

Hi Tom,
I did some calculations on the setup of your scope based on some assumptions of the focal length of the primary being 24", that is an F/15 system ie 90" focal length and the back focal distance being 10". If those are right then secondary to primary distance needs to be 16.84" and the baffle tube for the primary needs to be about 1.5" ID and 8.35" long ( from the surface of primary to top of the tube) The secondary baffle needs to be 2.38" in diameter and 1.90" long.
The secondary to primary spacing is critcial because the correction for spherical aberration is detemined. It also chances the back focal length and small changes in the secondary position are going to make a large change in back focal length. If you can get the exact focal length or radius on the primary and the convex radius on the secondary I'll be happy to recalculate the spacings and baffle dimensions.

- Dave


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: Dave M]
      #5943391 - 06/27/13 04:32 PM

Thats what he told me.It was in used cond. then, when Dan bought it in Texas.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5949519 - 07/01/13 11:51 AM Attachment (14 downloads)

Without proper baffling cassegrains suffer badly from sky fogging since light from the sky goes directly into the eyepiece. The cass. I'm assembling from vintage parts doesn't have any coating on the secondary at this time, so the image is dim. Without the baffle tube it is almost impossibe to see the image buried in the all the glare from the sky fog.
Here is a shot of the baffle I made from the Stables mailing tube. I just cut it to length and then took another section about 3" long and split down the slide and cut out a strip so it would fit tightly inside the main baffle and glued it in place. The fit was a little loose in the hole in the primary so I wrapped a couple of turn of printer paper around the end that were saturated with glue. The fit is snug now and I'll give the tube a couple of coats of polyurethane to seal it well and spray it flat black on the outside and line the inside with black velvet flocking paper.

- Dave


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5949522 - 07/01/13 11:53 AM Attachment (8 downloads)

Here is another shot of the tube showing the end that fits in the center of the primary.

- Dave


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5950254 - 07/01/13 07:46 PM

Dave, Nice work on the baffle, will it just be pressed in or will you put a tiny dab of silicon on it for final assembly ?

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5950320 - 07/01/13 08:36 PM

Very nice Dave, The scope that I have is my first attempt at restoreing a vintage cassegrain, I will need all the help I can get. So far yourself and everyone has been very helpfull in getting me throgh this project that I will start this fall, So I quess I will follow your lead, and this thread when the time comes to do my resto. Buy then hopefully you will have all the bugs (so to speak) worked out of your project, and can give me more tips that can help me on my scope restoration.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5950414 - 07/01/13 09:48 PM

Dave, I notice that your mirror retaining tabs are thicker and wider than mine. Is that a thicker and wider "BACKING TAB" for a thinner sheetmetal tab that goes on first to hold the mirror in place? I don't have that backing piece, will have to fab. 3 of them, good idea, glad i seen the inside of your cell.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5951175 - 07/02/13 11:29 AM Attachment (11 downloads)

Hi Tom,
Here is a close up of a backing tab. It's about 3/16" thick and like you said goes over the thinner tabs and they prevent the mirror from moving sideways.
You need to know the radius of curvature of the primary and secondary. With those pieces of information you can calculate the size and length of the baffles needed and also the spacing between the primary and secondary. Is there any writing on the mirrors that might indicate those measurments ?
If you have done mirror testing then the best way is with a Foucault tester and measure the primary mirror. Lacking that, then just using the primary mirror, project the image of the Moon onto a piece of the paper. For the secondary your going to need a spherometer. Since the secondary amplifies the focal length of the primary, a small change in it's position makes a big change in were the image comes to focus behind the primary. It also effects the optical correction of the system.

- Dave


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5951192 - 07/02/13 11:42 AM

Thanks Dave , Great picture, as far as the mirror's go , all I have is what you see,, and I don't have access to that kind of testing equipment. I will probably start with the figures that you worked up for me, and work with it from there.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5951439 - 07/02/13 02:30 PM

Tom,
For me to calculate the baffling and spacing I'll need the radii on both the primary and secondary. You can tape a card to the end of yard stick and put the yard stick through the hole in the primary. Aim the assembly at the Moon and move the stick back and forth until the Moon is sharply focused on the card. Then read the distance from the card to the surface of the mirror. You should be able to get to within 1/8". I'm guessing that it will be very close to 24".
As for the secondary, if you can get the use of set of machinist calipers you can measure the thickness of the secondary at the very edge and also in the exact middle. That will tell us the sagitta or depth of the curve and from that we can calculate a good approximation to the radius. From there you can assemble the scope and have enough adjustments in the cells to find the exact spacings.
Without some data on the radii you can be adjusting things until the cows come home and never get a good image. I wonder if this happened to the original builder and why he gave up on the project ?

- Dave


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5951631 - 07/02/13 04:07 PM

Dave,
I have a Foucault tester Tom can use, dont have the caliper though. My tester is identical to the Stellafane tester, and iirc it has a 120 line ronchi screen in it.
So Tom, there ya go, come get it


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: Dave M]
      #5951666 - 07/02/13 04:24 PM

Quote:

Dave,
I have a Foucault tester Tom can use, dont have the caliper though. My tester is identical to the Stellafane tester, and iirc it has a 120 line ronchi screen in it.
So Tom, there ya go, come get it




Dave,
That is great. Tom will also need to borrow the Ronchi grating from it once the optics are mounted in a tube so he can fine tune the position of the secondary using a star.
One can purchase a set of digital calipers from Habor Freight for under $15.
Dave, to answer your question about the gluing the baffle tube in place or not. I'm hoping that the fit will be snug enough once it is sealed with polyurethane and painted that I won't have to glue it in place.

- Dave


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #5951756 - 07/02/13 05:06 PM

Dave, Thanks!, i was just curious

Tom, the top of your pool table would make a nice test bed.
You`l need to make a mirror stand, pretty simple, just a couple pieces of plywood and a couple 1" dowels.
http://tinyurl.com/qgr7a8z
I know your going to ask how to use the tester and
ronchi.
Go here
http://stellafane.org/tm/atm/test/tester-4.html
and see the section " How do i use the Ronchi Grating"


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: Dave M]
      #5951841 - 07/02/13 06:18 PM

Sounds like a joint effort to me.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5951878 - 07/02/13 06:36 PM

Now dont be scared its really fairly easy.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: Dave M]
      #5951884 - 07/02/13 06:41 PM

But MASTER , I am but a lowly Grasshopper

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5951915 - 07/02/13 07:08 PM

I can help you get the readings, then maybe we can get Dave to do the calculations..Dave`s the Master

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5951925 - 07/02/13 07:15 PM

Quote:

But MASTER , I am but a lowly Grasshopper




Such knowledge is worth more than any fortune, Cookie!

-Tim.


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: tim53]
      #5951931 - 07/02/13 07:18 PM

Soon you too will be able to carry the hibachi grill with your forearms.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: starman876]
      #5972543 - 07/15/13 03:44 PM

Quote:

If I find everything for that 6" cassegrain I will post a pic. I bought it from the guy who made it in 1978. Looks like Toms, but it in a aluminum tube. Came with a 16X50 finder. No idea where that went.



Johann do you still have this? http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5665943/page...


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5972550 - 07/15/13 03:47 PM

Yep, still do. However, that is not that cassegrain I was refering to.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: starman876]
      #5972569 - 07/15/13 03:56 PM

Did you ever post pictures of the other one? This one is close but not a "Twin" to mine...Would you please post pictures of the other one sometime?

Edited by TOM KIEHL (07/15/13 05:06 PM)


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #5972586 - 07/15/13 04:06 PM

OK when I find time

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: starman876]
      #5972605 - 07/15/13 04:18 PM



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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6098736 - 09/24/13 03:38 PM Attachment (5 downloads)

Movin' right along,,,, got the mount finished and that took some time to do. Had to strip and refinish all three legs. Three hand rubbed coats of Shellac and one final coat of Varnish, topped off with 0000 steelwool and Johnson's paste wax rub out to finish for a satin sheen. Buffed all new stainless nuts and bolts to a mirror finish. Made a toe saver. Painted the cast iron parts with satin black paint. Applied green felt to cradle for OTA. Now on to the Technical part of this restoration........THE OTA.
OH YES... and a special thanks to "Gelkin" for his kind help.
Now on with the show.....


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6098741 - 09/24/13 03:40 PM Attachment (4 downloads)

#2

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6098742 - 09/24/13 03:41 PM Attachment (9 downloads)

#3

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6098745 - 09/24/13 03:42 PM Attachment (5 downloads)

#4

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6098746 - 09/24/13 03:43 PM Attachment (5 downloads)

#5

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6098749 - 09/24/13 03:44 PM Attachment (3 downloads)

#6

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6098750 - 09/24/13 03:45 PM Attachment (4 downloads)

#7

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6098752 - 09/24/13 03:46 PM Attachment (5 downloads)

#8

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6098759 - 09/24/13 03:52 PM Attachment (9 downloads)

#9........And thats all folks........For Now...Tune in latter , " For The Rest Of The Story"...

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6098764 - 09/24/13 03:54 PM

Great job Tom. The mount looks brand new. The legs are beautiful and I love the black color on the mount. Keep us posted on the restoration.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: terraclarke]
      #6098784 - 09/24/13 04:07 PM

looks great tom....did you spray mount with a gun.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: mustgobigger]
      #6098803 - 09/24/13 04:20 PM

No, Brian , Rattle can on the cast stuff. light coat of stain black over the original existing wrinkle finish, and the legs ,the old fashioned way, Brush In Hand. Going to paint the OTA ivory white....And BTW Thanks

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6098822 - 09/24/13 04:30 PM

That's come out fantastic, looks great. And those legs! Excellent job!

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6098823 - 09/24/13 04:30 PM

Tom,
Great job on the mount. Really nice. Did you get the optics mounted up and giving sharp images ?

- Dave


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: terraclarke]
      #6098837 - 09/24/13 04:34 PM

Thanks Tera, thought I'd get the mount done first so I had something to mount the OTA to, to do star test. This will be my first restoration of a cassegrain. Have to do all the optics from scratch, Baffles, and secondary shielding all of it...

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #6098840 - 09/24/13 04:35 PM

She`s got legs... ZZ Top!
Looks Great! Tom


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6098841 - 09/24/13 04:35 PM

Excellent Tom. Best looking edmund mount i ever saw. Nice work.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #6098878 - 09/24/13 04:54 PM

No , David , not yet , thats next , had to get the mount done first so I could do star test off of it.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: gelkin]
      #6098910 - 09/24/13 05:09 PM

Quote:

Excellent Tom. Best looking edmund mount i ever saw. Nice work.


...Thanks to you , you made it come together.

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #6597474 - 06/23/14 01:20 PM Attachment (7 downloads)

Quote:

Tom,
Great job on the mount. Really nice. Did you get the optics mounted up and giving sharp images ?

- Dave





Well Dave YES,,,Matter of fact. Just finished it about a week ago . I got tired of seeing it laying around unfinished so I decided to finally GIT -R- DONE thanks for all your help DID you ever get your DK finished????

Edited by TOM KIEHL (06/23/14 01:39 PM)


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597477 - 06/23/14 01:21 PM Attachment (7 downloads)

2

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597480 - 06/23/14 01:22 PM Attachment (5 downloads)

3

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597484 - 06/23/14 01:23 PM Attachment (16 downloads)

4

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597486 - 06/23/14 01:25 PM Attachment (7 downloads)

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597488 - 06/23/14 01:25 PM Attachment (7 downloads)

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597489 - 06/23/14 01:26 PM Attachment (8 downloads)

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597490 - 06/23/14 01:27 PM Attachment (7 downloads)

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597495 - 06/23/14 01:28 PM Attachment (9 downloads)

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597496 - 06/23/14 01:28 PM Attachment (9 downloads)

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597499 - 06/23/14 01:29 PM Attachment (6 downloads)

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597502 - 06/23/14 01:29 PM Attachment (8 downloads)

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597503 - 06/23/14 01:30 PM Attachment (6 downloads)

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597505 - 06/23/14 01:31 PM Attachment (7 downloads)

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597507 - 06/23/14 01:32 PM Attachment (8 downloads)

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597512 - 06/23/14 01:32 PM Attachment (11 downloads)

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597518 - 06/23/14 01:37 PM Attachment (10 downloads)

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THAT'S ALL FOLKS,,,,STICK A FORK IN IT,,,,,IT'S A WRAP,,,THE END,,,,THAT'S ALL SHE WROTE,,,IT'S FINALLY FINISHED......

THANKS TO EVERYONE FOR THE HELP


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DAVIDG
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597542 - 06/23/14 01:56 PM

Tom,
Looks great. So what do the images look like ? I haven't finished my DK. Got busy restoring the local high schools 10" Cave Cass. mount and dome.

- Dave


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TOM KIEHL
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Reged: 11/17/12

Loc: N.E. Ohio
Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #6597592 - 06/23/14 02:21 PM

Quote:

Tom,
Looks great. So what do the images look like ? I haven't finished my DK. Got busy restoring the local high schools 10" Cave Cass. mount and dome.

- Dave





Before I did the paint and finish... This winter I had it out for star test and star collimation Dave those test proved to be very good ..tooo cold to mess around too long outside. Think I did swing around and check out JUP real quick It looked good too. then back in the house. I took all the optics out to do the paint and finish ,reassembled and did a bench collimation last week. have to get it out to test and star collimate again soon I hope .then I'll have better weather conditions to play around,, then in the dead of winter


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6597650 - 06/23/14 03:00 PM

That is very nice Tom. It has the exact same finder as on my 4" F15 Edmund refractor.

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terraclarke
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: terraclarke]
      #6597655 - 06/23/14 03:03 PM

I cannot for the life of me understand why noone (or darned few anyway) makes a classical Cassegrain like that anymore.

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jrcrillyAdministrator
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: terraclarke]
      #6597675 - 06/23/14 03:16 PM

Quote:

I cannot for the life of me understand why noone (or darned few anyway) makes a classical Cassegrain like that anymore.




It's awfully long (slow) for a classical Cass. I'd think it more likely to be a D-K. The reason we don't see very many classical Cassegrains is that very nearly the same performance can be had by relaxing the mirror curves to a slower D-K, making a more affordable instrument. Or the primary can be pushed into a hyperboloid at a modest increase in cost and similar performance can be had in a much faster package. Both alternatives are much more popular than the original, which offers the least bang of the three for the buck.


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Bomber Bob
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: jrcrilly]
      #6597759 - 06/23/14 03:58 PM

A great restoration thread! Lots of inspiration as I get ready to work on my Edmund 4.25" mount. Thanks for the detailed photos and descriptions. Your Cass is a beauty! F20... 200x with an OR12.5 - excellent!

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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: Bomber Bob]
      #6597832 - 06/23/14 04:31 PM

The reason why you don't see classic Cassegrains is the difficulty in making the convex hyberbolic secondary. To do it right you need a Hindle sphere which is a concave spherical mirror that has the radius of curvature equal to the focal length of the primary used in the cassegrain telescope. So if your making a cass with F/4 primary you need to make a hindle sphere that is around F/2. On top of that, polishing a small convex hyberbola is not easy, especially getting the edge correct which is the most critical part. Here is a link to a my good friends Dick Parker's setup http://mirrorworkshop.mtbparker.com/hindleSphereBench.html
Dall Kirkhams are easier to make so more popular. Since the primary is an ellipse is has less correction then a parabola and the same test techniques can be used to make it as one uses to make a parabola. The secondary mirror is a convex sphere. Since a sphere has no optical axis you can grind a larger disk that is easy to handle then cut out the ssmaller secondary from it. When it comes to testing, the concave "tool" used to grind the convex secondary can be polished, figured and tested just like making any other sphere then used as a test plate to check the figure of the convex secondary by contact interference. So the testing the secondary is much easier as well. If your making a number of optical sets you can grind and figure a large enough disk to cut out the needed number of secondaries from just the one disk.
What you lose in a Dall Kirkham is off axis performance. It has much more coma then a classic Cass so the useable field of view is much smaller.


- Dave


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jrcrillyAdministrator
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #6598258 - 06/23/14 08:52 PM

Quote:

The reason why you don't see classic Cassegrains is the difficulty in making the convex hyberbolic secondary.




Don't think so. Other designs (RC, ACF, others) use hyperboloid secondaries and are still are much more common then the classical Cass. Even the RC, with not one but two hyperboloid mirrors is far more common. The CC is at the worst point in the performance/difficulty-to-produce curve. I liked mine (a Takahashi) but it wasn't a good value.


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Dave M
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6598319 - 06/23/14 09:27 PM

Nice looking scope, Great job on the restoration work..

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gelkin
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6598325 - 06/23/14 09:31 PM

Tom that looks fantastic. I really like how you polished the finder instead of painting it. Very nice indeed.

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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: gelkin]
      #6598432 - 06/23/14 10:38 PM

Quote:

I really like how you polished the finder instead of painting it. Very nice indeed.




Thanks Gerald, I was going for that UNI-CORN-ISH look


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: jrcrilly]
      #6598440 - 06/23/14 10:46 PM

Quote:

Quote:

The reason why you don't see classic Cassegrains is the difficulty in making the convex hyberbolic secondary.




Don't think so. Other designs (RC, ACF, others) use hyperboloid secondaries and are still are much more common then the classical Cass. Even the RC, with not one but two hyperboloid mirrors is far more common. The CC is at the worst point in the performance/difficulty-to-produce curve. I liked mine (a Takahashi) but it wasn't a good value.



RC are more common because they have better off axis performance then a classic cass so astrophotographers want them and will pay the high price to have someone do the hyberbolic primary and secondary correctly. AFC use correcting lens to get away from the hyberbolic figures and the lens greatly improve the off axis correction.
The Holy Grail in the optical industry is all spherical optics since it cheaper to have a system that has more elements but having them all sphreical then it is to have fewer and have anyone one of them aspheric. This is whay both Meade and Celestron come out with optical designs that use correcting lens. The correctors allow for spherical optics and correct the off -axis problems. Tak. sells a corrected Dall Kirkham with corrector lens system in the baffle tube for the same reason.

- Dave


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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: DAVIDG]
      #6602261 - 06/26/14 01:24 AM

Quote:

Tom,
Looks great. So what do the images look like ? I haven't finished my DK. Got busy restoring the local high schools 10" Cave Cass. mount and dome.

- Dave





6/25/14>>>>>> FIRST LIGHT REPORT<<<<<< WELL.. thats all the emotioncons I could use to describe this first light..FIRST...Set the scope up on my stellarview alt/az mount on a Hercules tripod. pointed it at Polaris and locked down the alt/az, very humid in the Buckeye state tonight seeing was not all that great it never is here maybe a 5-6 at best, lots of light pollution. Did a star test first on Polaris , and was amazed how close my bench collimation was. But that was not good enough for me tried to do the collimation with a 10mm eyepiece but found it easier with a 15mm = 100x got it fine tuned with the 15 and then tweaked it some more with the 10mm = 150x had good inside focus rings very nice, but the outside focus rings were different , don't know if the seeing was the culprit or not? the outside ring seemed thicker on out focus......SECOND... Got all that dialed in and then went for mars and it was in the trees,, so then went for Saturn it was on the meridian ,but had to shoot over the neighbors roof some heat turbulence,, But the image was very pleasing to the eye at 100x tried 150x but the seeing would come and go, so I dropped back to 100x .Nice crisp view of Saturn could make out 2 moons and a 3rd with averted vision , seen the Cassini division with no problem all around the rings,and as seeing came and went, between nudges of the mount was able to see some planet detail as in ,,what I call storm belting???and a real defined planet shadow, on the backside of the planet on the rings, and good crisp definition between the front of the planet as the rings passed in front of the planet...All in all it is what it is. and I'm pleased with my first Dall Kirkham cassigrain restoration, what a challenge .It was a lot of fun. and my sincerest THANK YOU to you DAVIDG for passing along your wealth of Knowledge on this project of mine. NOW you David need to complete your DK and enjoy IT, Good Luck ...........T.K.


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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6602524 - 06/26/14 09:16 AM

Tom,
That is great news. Glad to be of some help and many thanks for the kinds words.
As for the slight difference in the appearance of the rings from inside to outside you might need to adjust the spacing of the secondary very slightly since it's position does effect the correction of the system. If you can get them to look the same on both sides of focus, the spherical correction of the system will be at it's very best.
It sounds like the baffle tubes are also doing their job. A Cass, just won't give contrasty image without them. If you don't have them installed or installed incorrectly it's one of the big reasons see I these types of scopes them left in the basement instead of being used because the image is just washed out.
My DK is calling my name along with a 6" Mak. Hopefully over the long July 4th Holiday, I'll get back on it but the latest project is to finish up one of the original Hale spectrohelioscope that I'm restoring to be housed at Stellafane. Too many projects and not enough time.

All the Best,
- Dave


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Dave M
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: TOM KIEHL]
      #6602616 - 06/26/14 10:00 AM

Quote:

Quote:

Tom,
Looks great. So what do the images look like ? I haven't finished my DK. Got busy restoring the local high schools 10" Cave Cass. mount and dome.

- Dave





6/25/14>>>>>> FIRST LIGHT REPORT<<<<<< WELL.. thats all the emotioncons I could use to describe this first light..FIRST...Set the scope up on my stellarview alt/az mount on a Hercules tripod. pointed it at Polaris and locked down the alt/az, very humid in the Buckeye state tonight seeing was not all that great it never is here maybe a 5-6 at best, lots of light pollution. Did a star test first on Polaris , and was amazed how close my bench collimation was. But that was not good enough for me tried to do the collimation with a 10mm eyepiece but found it easier with a 15mm = 100x got it fine tuned with the 15 and then tweaked it some more with the 10mm = 150x had good inside focus rings very nice, but the outside focus rings were different , don't know if the seeing was the culprit or not? the outside ring seemed thicker on out focus......SECOND... Got all that dialed in and then went for mars and it was in the trees,, so then went for Saturn it was on the meridian ,but had to shoot over the neighbors roof some heat turbulence,, But the image was very pleasing to the eye at 100x tried 150x but the seeing would come and go, so I dropped back to 100x .Nice crisp view of Saturn could make out 2 moons and a 3rd with averted vision , seen the Cassini division with no problem all around the rings,and as seeing came and went, between nudges of the mount was able to see some planet detail as in ,,what I call storm belting???and a real defined planet shadow, on the backside of the planet on the rings, and good crisp definition between the front of the planet as the rings passed in front of the planet...All in all it is what it is. and I'm pleased with my first Dall Kirkham cassigrain restoration, what a challenge .It was a lot of fun. and my sincerest THANK YOU to you DAVIDG for passing along your wealth of Knowledge on this project of mine. NOW you David need to complete your DK and enjoy IT, Good Luck ...........T.K.




Way to go Tom..


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TOM KIEHL
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Re: ? MYSTERY ? EDMUNDS ? 6" CASSEGRAIN ? new [Re: Dave M]
      #6603011 - 06/26/14 02:50 PM

The scope is a dandy , But it is going to have to go along way to beat my 7" Meade Maksotov for high power viewing it's alot more user friendly with electronic slow mo Dec and RA control . But thats not fair to the DK it's like compareing Apples and Oranges.. But something has to be said for a F15 reflector,, the darn thing is just to cool, because it's OLD SCHOOL

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