proper rebuild the odyssey 8!

[garethmob]

have a few days off work so i want to at least plan and maybe even get some materials to start getting her into a proper working shape

i'll attach some photos of what iv got currently and any help or suggestions on any materials / work would be greatly appreaceated

[garethmob]

here we go

this is the uderside of the top base, a type of plastic, does have some groves from the 3 rings on the otherside of the base next image)

iv hered tevlon is a good base and the ebony star (bot that does seem to have vanished or gone stupid expensive:( )

this next image has the circular base parts that seem to have caused the groves on the other plastic

this is the center screw that goes through the 2 base's, it seems to tighten the circular motion (is the other base's on skywatchers the same?) for harder / eaiser movement

id placed the gemred rotary encoder next to the center screw unfortunatly i havent a way to attach it yet, but any suggestions will be good

one major replacement. the 2 side bearings are made from what looks like the bottem of chairs. one side is intact, the other side, ons broke and left a screw, and the other side is cracked

strange piece of rubber on the front of the base, resting scope when horizontal?

the drain pipe "helical" focuser litterally part of a drain pipe hopefully going to replace it

inside the sonotube, the internal part of the focuser

a strange side bearing? same type of material as the chair bottem any ideas what its for?

bottom of the base, havent remove this yet going to do so after a cuppa tea:), it has 3 screws with washers and 3 screws which iv assumed for collimation

and the last photo is of the side scope bearing!

sooo......... focuser and base plastic can be the first ones i attempt!

[Helen]

I'm about to pack up the focuser for you (couldn't locate all the bits earlier on before I had to go out). Have you got a 2inch to 1.25 reducer? If not, I'll send one of those too.

You can use 3 furniture glides instead of teflon pads - available at B&Q etc. Milk cartons also provide teflon-like properties so are useful for making washers to go around the central bolt etc

Helen

Helen

Helen

[nytecam]

You can use 3 furniture glides instead of teflon pads - available at B&Q etc. Milk cartons also provide teflon-like properties so are useful for making washers to go around the central bolt etc.... Helen

Brilliant tips:hello2:

[swamp thing]

The "strange side bearing" is to stop the tube from sliding laterally in the bearings.

Looks like the rocker box and ground board are made from Sterling board. This is often used under flat roofs. Horrible stuff to work with, but cheap and reasonably durable.

I would build a new mount from hardwood veneered hardwood core ply. It has a nice hardwood veneer face on it. And has more plys (stronger) than regular ply!and fewer defects (holes) inside the board.

This can be bought at any decent timber merchant (not Homebase, B&Q or Wickes type stores they only stock junk)

That's what I'm using on my Dob build.

Regards Steve

[garethmob]

Thanks Helen I don't have one of those

Thanks for the tips with the base Iv got a bottle of nealy empty milk now

Did you mean the metal tops or the plastic it's made from?

@swampthing I'll pop over to my local travis Perkins . Iv got no idea what to do with it mind I have a mate I could borrow some tools off I guess

I dismantled the mirror area and was very supprised to find something very interesting.

The size of the mirror height wise, the length of the screws(I think the black ones are collimating but no idea what the silver ones are. Their really long)

Also I thought the mirror was on a sling type mount. It seems really really solid

I completely faild to re collinmate as the focuser has just way too much play

But it seems once its collinmate it's not gonna need another one for a very long time

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[garethmob]

Helen what do you mean around the centre bolt?

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[swamp thing]

Aagh! the old jubilee clip and gaffer tape sling eh.

Not familiar with that design.

Is it a ply wood cell behind that tape? Not familiar with Odyssey scopes.

For small Dobs this may be a great help.

Build Your Own Telescope, Complete Plans for Five Telescopes you can Build with Simple Hand tools, by Richard Berry

You may find it cheaper elsewhere. But it's sure worth a look.

Regards Steve

[garethmob]

Ohhh that's what the sling is??'lol I see

It's all ply under the mirror different material to the dob base. I was thinking of something like a 6point cell. Are they any better?/ worth the price?

Not sure I assume that behind the bottem of the tape is wood. I hope so as the screws go fairy deep

There's a little metal cap on the bottom if I remove it and look up there's a hole and I can see the mirror. When the laser was on I could actually just make it out :s

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[Helen]

Helen what do you mean around the centre bolt?

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You've got a bolt that holds the base of the scope bit to the bottom board (the ground board) - the one you said you can adjust for tension. You want to avoid play in that or it'll wobble. When people add things like new bearings (like the furniture gliders) they cut disks from a plastic milk carton to allow them to get the height just right (by varying the number of disks until the tension is just right).

If I were you I'd do a google search if SGL for Dob mods as you'll find loads of brilliant ideas and pictures too

Helen

[swamp thing]

When designing a mirror cell the aperture and thickness of the mirror dictate what kind of support would be best.

This can help you design your own:

Automated Mirror Cell Optimization

Or if you don't wanna design your own

Design Techniques for Mirror Cells

And for edge support

Dobsonian Mirror Edge Support Calculator

These links courtesy of "Don Pensack":icon_salut: who kindly posted them for me on my Dob build thread.

These are the ones many use to help them design theirs. I'm sure if you PM Don he would give you some help if needed.

Buying one is an expensive option TBH. For my 20" scope to buy a 27 point cell would have cost me many hundreds of pounds. To make one is a few tens of pounds.

And it isn't hard trust me.

Regards Steve

[garethmob]

Ohhhh I see I didn't releise that I assumed it would work. Any ideas how I can find out thickness with out taking apart mirror and sling?

Soooooo. My list currently (things to do tomorrow:P)

*Cut milk into rings

*find out thickness of mirror

*set design of mirror fittings

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[swamp thing]

I guess it depends how confident you are about making a cell.

Orion optics supply cells. If you aren't that confident. Their stuff is highly regarded by a lot of guys and galls on here.

Optics Mirror Cells Page

You will need to know the thickness of your primary though.

Or you could try FLO they sell them too.

First Light Optics - Optical Supports Mirror Cells for Newtonian telescopes

Regards Steve

[garethmob]

I'll be honest. I'm confident around computers. Building fixing soldering(badly) but I'm not really confident at anything DIY like wood or metal:(

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[garethmob]

Would this wood do?

http://www.valeveneers.co.uk/vo.html

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[swamp thing]

Hi Gaz

That's just veneer leaves buddy. For building a base you want HVHC (hardwood veneer, hardwood core) plywood, this means the finish on the plywood is a hardwood veneer, and the core plys are hardwood too. This type of ply has more plys per thickness.

The more plys a ply wood has the better the quality. The plys are the layers you see when looking at the edge of the board.

Poor quality 1/2" ply may have 5 plys whilst good quality one may have 11.

Regards Steve

[garethmob]

Lol see what I mean? I'm no good at this:(

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