192 replies to this topic

[clamchip]

I think the reason Meade skipped the brown sugar glaze is because with all

the optional photo doodads on the tube it can't rotate.

Robert

 

Edited by clamchip, 05 January 2022 - 11:18 AM.

[deSitter]

I always thought it would actually be easier to have the entire secondary and focuser part of the tube rotate around a joint in the tube. I never saw that implemented. But it seems much easier than rotating rings to do.

 

-drl

[clamchip]

I've have seen tubes with a rotating upper section before, I can't recall where or if commercially

made or ATM, it may come to me.

It's a great idea and would require precision work so the scope doesn't loose collimation as the

upper rotates so more than likely they have been ATM.

 

Robert

[CHASLX200]

Or have 3 focusers on the the OTA and have a way to twist the 2ndary.

[deSitter]

I've have seen tubes with a rotating upper section before, I can't recall where or if commercially

made or ATM, it may come to me.

It's a great idea and would require precision work so the scope doesn't loose collimation as the

upper rotates so more than likely they have been ATM.

 

Robert

It would be a great constraint on accurate collimation - getting the optical axis of the mirror aligned with the mechanical axis of the tube is the hardest part. I am seriously thinking about this, any ideas about something to repurpose for the joint?

 

-drl

[clamchip]

There doesn't seem to be a chiseled in stone method for the joint, anything and everything has

been tried and it seems no one has had very much success. The problem isn't so much the joint

its maintaining alignment as the UTA is rotated. 

A rotating UTA (upper tube assembly) or nose as it's called by some may be just a dream I guess. 

 

Robert

Edited by clamchip, 06 January 2022 - 11:17 AM.

[flywing1]

I've have seen tubes with a rotating upper section before, I can't recall where or if commercially

made or ATM, it may come to me.

It's a great idea and would require precision work so the scope doesn't loose collimation as the

upper rotates so more than likely they have been ATM.

 

Robert

Nikon made a prototype 120mm newtonian OTA where you can turn a knob to rotate the upper section (most likely?), however the exhibit label/information card (this telescope is in Nikon museum) says it's used to rotate the primary mirror (which doesn't make sense to me).

 

https://astro365.exb...18_00585538.jpg

https://astro365.exb...18_00533323.jpg

https://astro365.exb...18_00514534.jpg

 

Original blog post:

https://astro365.exblog.jp/29603814/

[clamchip]

Wow that's interesting.

From what I see in the links you provided the Nikon primary moves for focusing and the eyepiece is stationary.

It's a prototype, so maybe it didn't work well or it was too expensive to make.

One advantage I can see is if the eyepiece is stationary this may allow a reduced diagonal mirror size.

 

Robert

[deSitter]

I have never examined a large lazy Susan turntable, but it's a good candidate for either rotating rings or a rotating nose. It could be fastened to the tube with 90 degree aluminum angle brackets. I don't know if such turntables are stable enough in plane - ?

 

-drl

[clamchip]

There may be too much play in that type of bearing, the balls and the races, etc.

From what I read (red)  most experimenters tried rotating the nose with mating flanges, one

on the tube, one on the nose, and Teflon between the flanges. 

 

Robert

[clamchip]

I went back thru the Cloudy Nights classified and found a ad for DS-10

tube mounting blocks so I messaged and still available so I bought the pair.

Now I can return my DS-10 to full original.

I don't relish the thought of doing gymnastics around a non-rotating tube but

my sacrifice will be for the collectors of the future and I'm a real originality nut

anyway.

I'm also going to match the original sky blue under the white and repaint to

the original color. 

Robert

 

Edited by clamchip, 16 January 2022 - 12:08 PM.

[sydney]

I have a DS10A that I bought from Astronomics in 1985. It is still in great shape, except my puppy chewed through the wire to the joystick of the 47M dual-axis drive corrector. I had also purchased the 280PG guide scope and rings.

Many years ago I removed the tube mounting blocks and added Parallax rings. I didn’t realize that there may be a market for the blocks. I still have them. I haven’t used the scope for awhile and have been thinking about selling it. It’s just kinda big to comfortably ship. I have a lot of good memories with that scope.

[clamchip]

What is the 280PG guide scope, labeled Meade made by Towa? 

I think I see holes in my tube for it, filled on the outside when it was repainted.

 

Robert

[DS-16A]

What is the 280PG guide scope, labeled Meade made by Towa? 

I think I see holes in my tube for it, filled on the outside when it was repainted.

 

Robert

I just cracked open my Meade accessories catalog from 1986 that I grabbed when I purchased my DS-16A. The 280PG is shown as a 2.4"  f/11.7 Photo-Guide Telescope. Not sure if it's a re-branded Towa. It included a diagonal prism and a 9mm (78X) crosshair eyepiece.

[clamchip]

Is it matching color with the main telescope or white?

I'm just wondering if a plain old white 60mm can be substituted and still be considered almost original

equipment.

 

Robert

[DS-16A]

Is it matching color with the main telescope or white?

I'm just wondering if a plain old white 60mm can be substituted and still be considered almost original

equipment.

 

Robert

It's white.

[deSitter]

I just cracked open my Meade accessories catalog from 1986 that I grabbed when I purchased my DS-16A. The 280PG is shown as a 2.4"  f/11.7 Photo-Guide Telescope. Not sure if it's a re-branded Towa. It included a diagonal prism and a 9mm (78X) crosshair eyepiece.

There was surely a Model 280 refractor, and 280PG is the same OTA (Photo-Guide), so yes Towa. Diebel was married to the daughter of Towa's owner, was Towa his name? There is also a 300PG, corresponding to the Model 300.

 

-drl

[DS-16A]

There was surely a Model 280 refractor, and 280PG is the same OTA (Photo-Guide), so yes Towa. Diebel was married to the daughter of Towa's owner, was Towa his name? There is also a 300PG, corresponding to the Model 300.

 

-drl

From looking at my Meade catalog, the 300PG was 3.1", f/15. Came with a diagonal prism and a 9mm (133X) crosshair eyepiece.

There was also a 210PG, which was a 2", f12. Came with a diagonal prism and a 9mm (67X) crosshair eyepiece.

Edited by DS-16A, 18 January 2022 - 01:36 PM.