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Dob base build begins!


Daz69
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I made a start on my new dob base build this afternoon. I have a stock of 3/4" birch ply which are large off-cuts from previous projects which will look good when sanded and stained. I used the dob mount build guide from the Sky at Night magazine designed by Steppenwolf. However I'm not too sure that the sides are high enough even though I followed the Excel auto config figures that came up for my my OTA dimensions. I don't know if anyone else has this Excel program provided with the magazine feature who would be kind enough to double check for me?  

I'm having a round base board rather than a square one, and the reason being is that I will mark the 360 azimuth degrees in this, and will have an illuminated pointer attached onto the base box. 

So far, I have made the round base board and sides of the base box by gluing and biscuit jointing several boards from the off-cuts., and these are in the clamps to cure overnight. I'm using solid single pieces for the base board and the box base, as well as the altitude wheels. I've also blown up one of my routers, not happy. Must've had too much dust inside, but I'll strip it down and check it on another day. Luckily I've got 4 others as well as the one in my router table, so I reckon I'll get to finish this before they all give up :D 

Rummaging through my odds and ends box, I found 3 brand new adjustable cabinet feet from when I put some units in the utility room, so that's a few bob saved. 

Tomorrow's jobs: Route the alt wheels. Cut the box base board. Size up the front and side boards on the table saw for final dimensions, and once done, drill and screw these together in order to place on the box base. No glue at this stage. If I am happy with the side height (very much doubt it), disassemble and route out the alt wheel cups, route out the side openings and sand all faces, white spirit wipe all boards, glue and screw, base box made. If I'm not happy with the height, I will glue and biscuit another piece of ply perpendicular to the other boards as this will give extra strength, like a one ended wooden bread board. Finish will likely be stain and varnish IF they sand nicely. If they don't then I'll apply a pore filler, re-sand and paint. 

I've not taken any photos so far as looking at photos of bits of wood isn't really interesting, but when It starts to come together I will get a few.

I have also given some thought to making fine alt and az adjustment controls like fiestazetecmk2 has recently made. I have an alternator pulley from when I changed my old solid pulley to an over-running pulley on my car last year. I've also got some M10 threaded rod, will just need to get some other small bits, including a drive belt, however I do have a new one for my car hanging up, but will have to check for length. I'll make the hand wheels from wood (cheap skate!) and I have a good idea to help make them better to grip. However, these controls are not important at the minute, so they can wait.

 

 

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22 minutes ago, Daz69 said:

Thanks @estwing One day I'll have a scope as big as yours. That is mahoosive! :D 

Sounds like you are enjoying yourself, I look forward to seeing the completed build?

I hear on the grapevine that estwing is going for larger scope ?

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Just now, Uplooker said:

Sounds like you are enjoying yourself, I look forward to seeing the completed build?

I hear on the grapevine that estwing is going for larger scope ?

He'll have to apply for planning permission surely, and stick a flashing red light on the top for passing aircraft :D:D  I can't wait to see it! 

I do enjoy making things, keeps my mind occupied and off my head issue, but it just takes me longer as I am always treble checking everything before committing. 

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A bit more done today. Box panels are all cut to size and square, Sides have had the alt bearing cups cut out and the large holes routed out, just need to round over the holes for aesthetics. I've screwed the box together dry (no glue) but I still think it's too low. I'll get everything ready (only got the "dovetail" spacer bars to make which will be 3/4" ply) and build it all up and then see just how high up the eye piece is. Once I'm happy, it'll all be broken down and every panel sanded, then the box can be glued and screwed ready for the finish. Still no photos while they are all single bits of boring wood :) but once I get it all together tomorrow with the scope on and while it is still the dimensions given, I'll take some photos  just in case I do glue on another few inches to the box sides and front. 

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Quick question, If you have made such a base, where do people keep their dob bases and scopes that have these large alt wheels still attached, or do you remove the wheels (and tube rings) and bring your OTA's indoors? 

Edited by Daz69
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We store ours out in the shed, assembled (came as 11" newt).  As to height - that was dictated by the balance point of the scope, bottom of scope just clears the base when moved from vertical.  

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Hi guys.

I put it all together, still got to do lots of finishing to do, so it is in the rough at the mo.

dob%20base%201_zpsczlh8c1y.jpg

In this next photo, you can see that it is way too low, even though I followed the measurements given to me by the excel spread sheet. 

dob%20base%202_zpsh3l9pos2.jpg

With the scope set in the position you see (51 degrees) it is 2 feet too low if you put the centre of the draw tube at my eye line, give or take an inch. I know I can rotate the tube a bit, so I may be able to just add 20-22" on the bottom of the box. The actual platform has the adjustable feet wound right in, and I reckon I've got about 3" of allowance on the feet. 

I've never had a dob before, so tell me if I'm going wrong here, but I cannot see myself bending over for a few hours, as my back will not be able to do that. 

Regards

Edit: Forgot to mention, the tube is in the rings with the balance point centred between the rings, and that was checked with the finder scope and my heaviest EP in.

Edited by Daz69
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10 minutes ago, Moonshane said:

Great job!

This might give an idea re the eyepiece height ;)

 

Thank you. So you're sat in a chair when you use yours? Aren't you forever having to move the chair all the time to follow an object? I prefer standing, so think I will have to add the height I need, keeping in mind the top heavy likeliness that will be as a result. I'll have a look through and see if there is a thread for "show us your dob" and see what heights others have done. 

Thank you. 

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Definitely follow Shane's advice regarding a chair. It will allow you to exercise your DIY skills again by building a cantilever chair. Sitting while observing improves the whole experience immeasurably.

Sorry, forgot to say well done. That is a mighty fine looking dob. Just need to increase the aperture to gain access to the Dob Mob ?

Edited by Uplooker
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ps

it takes about 1 minute for a planet to cross the field of a plossl at 150x in your scope i.e. between nudges. so after about 20 minutes or so you might have to move your chair or of course when you go for a different object. it makes for a much steadier platform too, and reduces back ache a lot!

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15 hours ago, Uplooker said:

Sorry, forgot to say well done. That is a mighty fine looking dob. Just need to increase the aperture to gain access to the Dob Mob ?

So, even though I have built a dob, I still can't be a "Dob'ster"? Fine, that's it, I'm going home! :(  :(  

So, after taking Shane's advice, I got my workshop stool which is one of those gas adjustable types with castors (I use it for drawing and making my RC planes on the model bench) and tried it with the tube at 51 degs. and it still left me hunch backed, even more so when the tube is lower, so I've added only 5" to the bottom of the sides and front. That allows my chair to lowered right down and still be comfortable. By using the stool I don't have to get up, I can just scoot along on the wheels. 

Mrs Daz had said the other day that I can build an area of decking for observing, which will be at the end of the garden, so I won't be able to use the stool on the grass for the time being, but will be able to use it on the patio. The reason for not wanting to use the patio is that it is right next to the house and I don't want to keep getting disturbed by the kitchen lights coming on. Well I guess once the dob is finished I'll be making a decked area :) 

Jobs for today, finish the round over routing, sand the panels, go to the charity shop to buy an LP, hardware store for a centre bolt because the one I had planned to use may be about 5mm too short, glue and screw the lot together. Painting will be another day I think.

Thank you for the advice Shane and Ian. 

Edited by Daz69
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Looking good Daz :)

23 hours ago, Daz69 said:

Quick question, If you have made such a base, where do people keep their dob bases and scopes that have these large alt wheels still attached, or do you remove the wheels (and tube rings) and bring your OTA's indoors? 

I leave my 10" assembled for storage. When moving it about I carry it in two parts though (it's just easier). 

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A bit more done today. I took the boards out of the clamps and sanded the joints on all three boards. Cut the box base board and stuck it all together. I put the whole thing together on the base board using a large washer (just for this set up) between the box and the base. Stuck the scope on to see what the difference is going to be.

dob%20base%204_zpsbqyg7wjq.jpg

I then got the stool and gave it a try for size.

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I'm now much happier :)  I have planned all along to put my battery box and power distribution box inside the dob base so I don't have any wiring outside of the base that can get snagged or tripped over, so that will add a bit of ballast. I then too it all down, removed the alt wheels and routed out the beautification holes (hand holes :)) and rounded over those. I then set to with the filler and went over all of the joints and end grain, as the ply had a few voids. I haven't put any filler one the outside of the alt wheels as I want the adhesive for the formica to stick to wood, but everything else has been done.

dob%20base%205_zpsuapbi6vu.jpg

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I'll let the filler dry overnight, and rub it all down tomorrow and start painting the primer on. I popped down to the local charity shop and bought a Shirley Bassey album (it was that or Cliff Richard) and opposite is our local hardware store. I got my centre bolt and had a look at their T nuts. For some stupid reason, they stock metric nuts and bolts, but imperial T nuts! Even the shop worker couldn't figure. Luckily, there's another little shop on my home from work, so I'll pop in there as I pass through. 

So far, it is all going fairly smoothly. Unfortunately with the way my head is and the brain fog I suffer due to my meds, everything takes so much longer for me to do, however, do it slowly do it right! I'm going to paint this white, as that's what I have got in abundance, rather than go and buy even more paint for the remnants just to sit on my workshop for another 5 years!

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