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6" f5 suitcase dobsonian project

Moonshane

By Moonshane
in DIY Astronomer

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ismangil

ismangil

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unlikely Perry - the problem is, I am beginning to understand why David Lukehurst and Sumerian charge what they do! the woodwork is the easy bit!

All the merrier, if you want to charge close to their prices, this is about custom ultra portable Dobs.

For example, as good as Sumerian design is, if I am spending that amount of money, I wish to have a split suitcase model, where the delicate bits, mirrors goes as hand luggage size and weight(< 7kg) the rest can go as checked baggage.

Perry

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Moonshane

Moonshane

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got the mirrors in and did a rough collimation last night to allow me to establish the focus point and thus the length of the final poles. pit in a BGO (most inward focusing eyepieces in my collection) and the 32mm TV plossl (at the other end) and neither would focus. So I took out the 2-1.25" adapter and held in the 32mm to a point where I could see stars. This turns out to be 90mm in from the current position. Therefore I need to reduce the length of the poles by 90mm. This seems to be a good thing as although there are no teflon/formica bearings in place yet, it already balances quite well. therefore with the reduced length of the poles the balancing will move toward the bottom end. it's possible it may even be bottom heavy - much more easily resolved than the other way round.

should be in a position to cut the adjustables and recheck this weekend, get it to the point where it will focus all eyepieces and then cut the permanent poles too.

then I can start adding bearings and painting. to allow the whole thing to be bolted to the ground, I may add some eyes on the legs to allow tent pegs to be pushed into the ground for star parties etc.

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  • 2 weeks later...
Moonshane

Moonshane

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quick update. we have made the trusses, cut to the correct lengths now and these all fit - goes together well. I'll be adding matt black heat shrink to them to dull them down. now in filling and sanding mode getting the parts ready for painting in due course. I then just have to add the bearings (formica and teflon), the UTA inner plastic trim and flocking and then rebuild with focuser and optics etc. and make a shroud.

hope to get the painting done next weekend. I'll upload pics then.

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  • 2 weeks later...
Moonshane

Moonshane

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been thinking about how to get weight down and decided to bite the bullet and router some shapes into the various parts. I stuck with a simple design and a repetitive pattern.

managed to get total weight (inc 6" mirrors and focuser etc) to 10KG which is OK I think.

also, I felt the alt bearings were a bit clunky so cut them to a crescent moon shape. also got the truss tubes sorted with heat shrink. lots of filling and sanding now in prep for painting over half term break. look forward to using it again!

considering one of the Antares helical focusers to reduce weight further. anyone used one?

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spaceboy

spaceboy

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Not had experience of using the Antares focuser but I have used a cheapplastic helical focuser on the 130P dob I had and despite it being quite sloppy it was nice to use. If the Antares was a more refined model then I would recommend using one.

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Moonshane

Moonshane

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Sounds good Shane, come on then, let's see some pics.:)

ha ha - patience my friend, patience.....

didn't have time yesterday but will try and upload some later. the thing is covered in pencil marks but will look better after a good rub down. should have it finished within another week or so.

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Moonshane

Moonshane

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Not had experience of using the Antares focuser but I have used a cheapplastic helical focuser on the 130P dob I had and despite it being quite sloppy it was nice to use. If the Antares was a more refined model then I would recommend using one.

cheers Nick - I think I'll order one and see what it's like. I am sure I can always use it in due course either way.

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swamp thing

swamp thing

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Mmmm Mmmm! Sweeeeeeet.:)

What are you gonna cover the holes in on the box it all folds into Shane, A non porous material of some kind or are the mirrors removed for transport?

Go on give us a clue about the colour too.:)

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Moonshane

Moonshane

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cheers Steve

I am likely to make a bag for it to go in out of webbing and garden weed material (and will also make a shroud and cover the inside of the holes on the rocker box with the same material, glued in place. the whole thing will stay together for transport (although the trusses will be in their own little bag).

the colour of the scope will be satin black which will look good I think and be suited to our nocturnal habits. I think I'll add some screw in eyes on the inside of the feet to enable the whole thing to be pegged down for windy conditions.

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