Dob Base Build 10" [Archive]

davewaldo

12-09-2012, 07:53 PM

Hi Everyone,

I thought I'd post my progress for my current build. This is my first attempt at ATM, and I have to give a big THANK YOU to mental4astro for all his advice.

As you might have seen, I've been selling off a lot of my gear as I'm getting out of imaging and back into visual astronomy. This is mainly because I simply don't have much time for this hobby anymore. So I began looking for a good dob... but in the end I decided to make a dob base for my 10" Sky-Watcher newt as this would be much cheaper and I hope MUCH better than cheap commercial dob bases.

So I came up with a plan with much assistance from mental, see attached plan. The cut outs are meant to represent celestial bodies. I stole mental's use of the large disc with a smaller disc on either side, this symbolises how Galileo first pictured Saturn. My design on the side is meant to resemble a moon disappearing into the planets shadow... but looks a bit more like a snowman! :lol:

So to date I have cut out all the parts and have them sanded awaiting assembly. I'm using 15mm marine ply and I've sourced virgin teflon AND secured a massive sheet of ebony star :eyepop: (must be the last piece in QLD!!!). I was stoked to find the ebony star, I rang around and visited loads of kitchen places, in the end I went to a benchtop wholesaler and the foreman found their last piece tucked up the back of the warehouse, its 650mm x 2.2 meters long! And the best bit... I offered $45 as it was old stock and they happily obliged!

My plan is to stain a medium walnut colour and finish with satin exterior poly. Also I've purchased an Argo Navis that will be installed. Not sure yet how I'm going to mount the handset....

I've been enjoying the build, this is my first time cutting circles with a router, but after using my brother's little laminate router I simply have to have one!

Anyways, here are some pics.

Dave.

davewaldo

13-09-2012, 02:02 PM

So today's progress....

I did a dry run with the scope to make sure it was all going to go together as planned. Happily everything fits together beautifully and I experimented sitting at the scope and using it at various altitudes and its very comfortable.

After the dry run I glued up the rocker box ensuring it is nice and square.

In the first pic showing the inside of the rocker you can see a side brace I've made to help strengthen the tops of the cradle (good suggestion mental:thumbsup::thumbsup:). I made cutouts in the corners of this brace to allow routing of cables.

I also did a stain and varnish test run on some offcuts today, we'll see how they look tomorrow ;)

Here are some pics :)

Dave.

Varangian

13-09-2012, 02:28 PM

Big fan of the 10" Dob for capability and mobility. Your mount looks very professionally crafted and unique. I love mental's Dob bases and I love what you have done here. The timber looks great with the blue Newt.

Well done.

mental4astro

13-09-2012, 03:40 PM

ATM is all about innovation. Taking this and that idea and then adding your own twist to further the "DNA" of scopes.

Dave, I just love the internal brace you've made. Such lovely curves, ;) .

Mate, I can't wait to see the end product and how it responds at first light! Hurry up, sunshine :evil2: ...

Shark Bait

13-09-2012, 03:58 PM

Looks like a fine piece of woodwork. Long term, the ply will be so much better than mass produced chipboard bases.

Are you still going with the Argo Navis?

Stu.

davewaldo

13-09-2012, 05:02 PM

Thanks John, I too think the 10" is a good sized scope, and the biggest I'd get in a solid tube. A 12" collapsable is temping though.....

Thanks Alex, its funny, I also find that brace very nice to look at :lol:
You think YOU can't wait for it to be finished!!! I'm dying to complete it. I've been on holidays this week, but back to work on Monday so progress will slow sadly. But I'm hoping to have it assembled by then and the finishing started at least.

Thanks Stu, yes I'm hoping this base will last many years - the marine ply is beautiful stuff, its a 9 ply and machines nicely. I've got an Argo Navis sitting on my desk and can't wait to fit it. Gary has been amazing helping me plan my base and the argo install. He even custom made me a pivot bolt to my dimensions!

I'm really hoping this will be a smooth and pleasurable base/mount to use, it will end up being worth more than the scope!

Dave

davewaldo

14-09-2012, 06:55 PM

Not a lot to report today, I glued everything up and cut the azimuth pivot holes. The pic attached shows how I ensured the rocker was exactly centred over the pivot hole. I used fine copper wire and strung it corner to corner - easy. Finally I wet all the timber down (to raise the nap) and I'll give it a final sand tomorrow before staining the lot. Hopefully I can cut out the laminate too, ready to be glued once the varnish is on.

Not far now.... :D

davewaldo

15-09-2012, 08:31 PM

Stained today, went on a bit heavier than planned but I think it'll look nice.

davewaldo

18-09-2012, 05:24 PM

Well, I've moved the project out of my brother's shed and I'm back home to finish it off. Here is a pic showing how the grain is looking after the first coat of poly. I'm quite happy with the look. :)

Dave.

davewaldo

23-09-2012, 04:02 PM

A quick update:

I've almost finished gluing the ebony star into position - the azimuth disc is done and only one alt disc remains to be trimmed (the other is ready for more poly).

Then its just 2 more coats of poly, some teflon and its finished! Can't wait!

davewaldo

27-09-2012, 02:39 PM

Well here it is! Its not quite finished yet but I couldn't help myself, I had to assemble it to test out the balance and teflon positioning.

It currently only has 2 coats of poly, and I plan to put at least one more on, probably two.

I'm VERY happy with how it has turned out and it looks like it will be a pleasure to use. A big thankyou to Alex for all his help during the planning stages and putting up with all my questions during the build.

One issue I discovered today is that the discs don't attach to one side of the scope perfectly square so will need some careful shimming.

One thing not shown in the pics is that I have attached some ebony star to the inside of the discs so that I can place a small tab of teflon on the inside of the cradle to eliminate sideways movement of the discs. Attaching these and the alt teflon is all thats left to do other than more coats of poly. Oh and then I can mount the Argonavis. Once the mount is finished the OTA will be next to be refurbished, I have a FT focuser and plan to get the OTA powdercoated, but what colour????

Thanks everyone for looking and your support. I can't wait to get back into this hobby and enjoy visual observing once again! :D:D

Dave.

mental4astro

27-09-2012, 03:01 PM

Bloody gorgeous, Dave!

Nothing else I can say really.

The stain & varnish is beautiful.

Colour suggestion? First is leave it as it is, then maybe metallic gold/manganese. The blue works well with the stained ply. I wouldn't go white or black. Maybe even one of those two tone paints that change colour in different directions. If you're going to go to so much trouble then make a statement. You can always have it sprayed to look like a cannon, laser or rocket. The last two would really endear you to the Spooks if you take it to a public place! :eyepop: :lol:

mental4astro

27-09-2012, 03:26 PM

I've had a bit of a think about your alt disks. You've only got a couple of screws holding them in place. With the load they are supporting the will always flex out. Look to strengthen the coupling mechanism to the tube rings as that is the weak spot. That's the reason why I prefer the more cumbersome looking box-cradle around the tube that holds the alt disks - no flex then.

Maybe if you fashion a plywood arc to act as a third tube ring that only reaches over the top of the scope to give you a third point along the top of the disks, this will stop the flex.

davewaldo

27-09-2012, 03:36 PM

Thanks Alex for your kind comments :) And I too think I should do something interesting with the tube colour!

The alt discs actually attach to the tube rings very securely and rigidly as there is a flat mounting pad on the rings. Once screwed on tight there is far less flex in these parts than in other areas of the mount (which only has minimal flex). I will need to ensure they are square though. I'll give it a try as is, I can always fashion a support bar that goes between the discs and sits under or over the tube (or both). I'm not sure why they didn't go on square today, when doing a dry run early on they sat very square, so maybe I just need to be more careful doing up the screws.

EDIT: wrong name sorry

davewaldo

27-09-2012, 10:34 PM

Sorry Alex, I called you Mark, that will teach me to write forum posts while sending SMS's. I've fixed my post above! Doh!

davewaldo

08-10-2012, 02:36 PM

Well its finished! And I'm proud as punch! A big thanks to Alex for his help, and for the support from this forum.

I still am working on a plan to mount the Argonavis hand pad, but I want to use it for a while first so I know where the best position will be.

The mount works like a charm, now I just need to make the scope look as nice! And like magic, today its started to rain!

Cheers,

Dave.

gary

08-10-2012, 03:20 PM

Hi Dave,

Turned out fabulous. Congratulations! :thumbsup:

And now if that rain will just stop for you ...

Best Regards

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place, Mount Kuring-Gai
NSW. 2080. Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
sales@wildcard-innovations.com.au
http://www.wildcard-innovations.com.au

davewaldo

08-10-2012, 05:39 PM

Thanks Gary, I finish my shift tonight at 11pm, if the skies are clear I don't think I'll be able to stop myself trying for a first light. :D

mental4astro

08-10-2012, 06:57 PM

Hmmm, first light on 47 Tuc after alignment? Then push the puppy for the Grus Quartet centred on NGC 7590. Then across to NGC 1365 should be a good test of your build coupled to the Argo, ;) . Pin these three and you've got a monster set up! Not a challenge for the scope, but their spacing will.

Dave, your build is a joy to the eye. The lines, curves, geometry - lovely, mate.

Mental.

davewaldo

09-10-2012, 10:28 AM

Thanks Alex, I'll put my system to the test as you suggest as soon as these damn clouds go away!

Dave.

davewaldo

10-10-2012, 08:36 PM

Well first light is happening. Its a pretty average night, very windy but I'm having fun.

I've set up the argo, I wasn't convinced I did a good alt reference, but I did centre the two star alignment well. And everything I've searched for since has been well within an 8mm EP; usually about 1/3 off centre. And this is all over the sky, I'm stoked! The balance is working well and overall its a pleasure to use!

One happy camper :)

gary

10-10-2012, 08:42 PM

Great to hear first light is happening and you are finding stuff.

Congratulations!

With cloud and rain forecast for most of the country tomorrow, it is undoubtedly testimony
to what a good mount it is. Enjoy it tonight whilst you can!

mental4astro

10-10-2012, 09:37 PM

gaa_ian

10-10-2012, 10:27 PM

I love it Dave !
I have a Circa 10yo dob and the chipboard base is looking pretty shabby !
I was going to just trace out the old base once disassembled and do in Ply.
However your setup has inspired me to go that one step further for a very tidy customized finish. What was the all up cost ?

Larryp

10-10-2012, 10:42 PM

That is one nice-looking dob!

davewaldo

10-10-2012, 10:55 PM

Thanks Gary, your Argo has helped me find objects I never could from my back yard. The skyglow tonight was really bad; I managed to find the Saturn nebula for the first time, I couldn't see it in the 25mm EP, but once I had the 8mm EP in, there it was, just off centre! I think I tested the pointing quite well, at all points of the compass and near zenith all objects were in the 8mm EP. It's performing great, I couldn't be happier with it. And I honestly just plonked it down, the base was certainly not 100% level, and did the basic alignment.

Thanks Ian, I'm glad you like it! I'd certainly recommend designing your own base to suit your needs. Its a very satisfying process. Not to mention it looks better, is lighter, and functions SO much better. I think all up the cost was about $300 total materials. But this includes more than enough ply to make another base, and enough ebony star and teflon for another 4 bases! So I would guess the actual "used materials" to cost about $150 or less. Obviously this doesn't include the Argo. This was using top quality marine ply, a base could be made much cheaper and still function better than a cheap factory base.

I also found some sailkote dry teflon lubricant at my local marine shop. This stuff is amazing and has made the azimuth motion incredibly smooth, highly recommended!

:D

mental4astro

11-10-2012, 07:18 AM

Marine grade ply also isn't necessary to be used. Common everyday exterior grade pine plywood will perform just as well. All that hardwood ply's do is resist dings a lot more than the softer pine. Mechanically they offer nothing more than extra weight. Not my thoughts - this is stated in the Kreige book "The dobsonian telescope". Better water resistance with hardwood or marine grade ply - nope! That's what the varnish is for.

The benefit from pine ply is reduced weight and cost. Some people may not like the look of it or its tendancy to yellow with age, but I make the most of the knots to make a highlight of the timber when I make dobbie mounts.

Ebony star is expensive stuff - though Dave found the bargain of the century (I hate you, Dave :mad2:). But there are also cheaper alternative laminates that can be used. You'll find these noted in post No. 14 of the ATM non-astro sources (http://www.iceinspace.com.au/forum/showthread.php?t=65307) sticky, along with many other material and source alternatives.

Careful consideration of materials and you'll be able to make a dobbie mount for half what Dave quoted for his, and work equally well.

lacad01

11-10-2012, 11:31 AM

Nice work Dave, very elegant looking base :thumbsup:

davewaldo

11-10-2012, 02:16 PM

Thanks Adam :)

Yep Alex you're right. Maine ply isn't nessecary, I only chose it as it was the nicest quality and my particular sample wasn't much heavier than pine ply. Also the $150 I quote includes buying sand paper, exterior varnish, glue and stainless steel screws. I reckon a good 10" base could be made for closer to $50 if you wanted.

But I never do things by halves :lol:

AG Hybrid

11-10-2012, 08:07 PM

A very pretty base indeed. Clearly too good for the blue tube sitting on it. Next project is converting that 10" tube into a fine truss structure.

davewaldo

12-10-2012, 05:50 PM

Yep, the scope is next on the list. Not going truss just yet, I think it will just get powder coated and I'll be installing my FT focuser. No idea what colour yet, open to ideas! I quite like the maroon or red.... but the electric green is a great juxtaposition to the nice antique wood look :D

Shark Bait

12-10-2012, 06:16 PM

Looks great. You and Mental have got me thinking about upgrading my dob's factory mount.

If it is going to be a close call between maroon and green why not go for the paint that changes colour depending on what angle it is veiwed from (with a metallic fleck).

I like the orange against the dark wood finish.

Any chance of a photo with the Argo Navis in place?

davewaldo

12-10-2012, 07:25 PM

Thanks Stu,

Here you go, This is a temp install, I've just strapped it to the alt disc, but I plan to mount a removable ball joint to the disc to allow articulation of the argo mount. I was using it set up like this the other night and it works well. Because its on the alt disc it moves with the scope and always points towards the EP.

Dave.

gaa_ian

13-10-2012, 01:51 PM

Great advise Dave
I am amazed my base has lasted so long, it has been in planes, carted along rough bush tracks, been peeed on by camp dogs in aboriginal communities :rundog: & endured muliple dewy nights.
I imagine a base like yours would last a lifetime.
Sounds like a project to do with a few other Dob owners who need a new base. Might make a good club project :question:
Cheers
Ian

davewaldo

14-10-2012, 01:26 PM

Thanks Ian, I hope my base will last a long time, I'm sure it'll need a new coast of varnish every few years.

Totally agree that dob base making would be a great group project and would be a much more efficient process. With a few templates, quality bases could be knocked out quickly. Fun times...

Dave.

gary

16-10-2012, 12:06 AM

Hi Dave,

I hope you don't mind, but below are a couple of artistic treatments of your scope.
Not as beautiful as the real thing though! :)

Best Regards

Gary Kopff
Wildcard Innovations Pty Ltd

davewaldo

16-10-2012, 11:01 AM

Wow Gary, I never thought my base would be immortalised in art! Thanks Gary, these are very cool! Can you send me hi-res to my email?

gary

16-10-2012, 12:40 PM

Thanks David,

Emailed. :)

Best regards

Gary

gary

17-10-2012, 12:22 PM

Hi Dave,

... and just for fun, here is a raytraced artistic interpretation. OTA rendered in a metallic maroon.

Best regards

Gary Kopff
Wildcard Innovations Pty Ltd

davewaldo

17-10-2012, 05:56 PM

Wow Gary you're going all out! :lol: Looks very cool, at this stage I am leaning towards a metallic maroon for the tube.

So here is my final set of pics, these show the little mount I've put together for the Argo Navis. Its based on a tiny Slik tripod ball head (http://www.digitalcamerawarehouse.com.au/prod7924.htm) that I've mounted to a homemade dovetail for a finder bracket. I've mounted the finder bracket to one of the tube rings as I'm still very reluctant to drill or screw anything into the beautiful wood. To attach the quick release plate to the argo holder I made a ply mounting plate stained to match the base.

Total cost: $29 (I had all parts except the ball head). The ball head is 100% aluminium, and I think its a bargain at $29.

This mount allows me to easily point the argo where it is best viewed, quickly and easily clamping it into place. Once clamped the unit is VERY solid. But it also allows me to both quickly release the argo for storage and leave the ball head behind; or remove the ball head too just leaving a finder bracket. The finder bracket also aims just between the focuser and existing finder so I can mount my laser or other finder on there if desired.

All up I'm happy, I don't really like the pole type argo mounts for small dobs, they just seem to take up much more space than needed and interrupt the smooth lines of the base. This mount allows me to easily hide it all away if I'm not using the argo, and its only one small piece to store.

Here are some dodgy iphone pics :)

Dave.

gary

25-10-2012, 05:34 PM

Hi Dave,

Love the elegant solution you provided by using the tripod ball head. :thumbsup:

I actually went to the trouble of modeling a simple ball head for use in the raytraced image before I
saw the type you used. Ironically the camera viewpoint I chose for the image I posted obscured it anyway.
But you can imagine it is there. :lol:

Best Regards

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place, Mount Kuring-Gai
NSW. 2080. Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
sales@wildcard-innovations.com.au
http://www.wildcard-innovations.com.au

ausastronomer

25-10-2012, 07:40 PM

Hi Dave,

The scope looks really great. A lovely piece of work.

A custom built base will give the scope movements way better than the standard base. Bigger altitude bearings and the correct bearing surface materials make an enormous difference to the scopes motions and the ability to easily hand track at high power.

BTW Tube colour = Fluoro Green

Cheers,
John B

davewaldo

26-10-2012, 01:57 PM

Thanks Gary and John!

Yep, its all working a treat, I'm just waiting for my feathertouch adapter to arrive and then I'll start thinking about getting the tube painted/powdercoated.

It seems to be coming down to either the metalic maroon or the fluro green!

I think the Maroon looks the most classy, but the green is the most original and fun. I do wonder however if people are recomending the green because they'd love to see it, but perhaps they wouldn't want to own it in that colour :lol:

I'll start checking out powdercoating places to see whats available.

Dave.