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Post by boomboom on Sept 29, 2013 3:37:49 GMT -5
And a few more. The cell, needs to be glued and is a tight fit over the tube. The focuser flange and one of four rear discs, will need to wrap tape around for a tighter fit. TBC Matt
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Post by boomboom on Oct 16, 2013 18:17:03 GMT -5
Some progress at long last. The plywood lens cell has been glued and an aluminium ring glued and screwed to the top for the push pull screws on the objective. All gone together without a hitch so far. Needs a bit/lot of sanding.... Weighs in at a 2.9 kg, 6.4 lbs. At the focuser end I am using an Antares adaptor for a 120mm scope with an 86mm GSO adaptor and linear bearing focuser. Inside baffles are still to be threaded onto 3 m8 threaded rods, maybe a bit heavy? Baffles at the moment are cut out of 8mm ply. Should I knife edge all of these? Will knife edge the first one closest to the objective and have to do that with a sharp chisel by hand which takes time. Would thin aluminium sheet be better? After the focus end is together it's on to a board to work out the tube length. Enjoying this so far. Matt
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Post by Kitch101 on Oct 28, 2013 21:50:57 GMT -5
Any more progress Matt I am hoping to get to the lathe on Thursday to make some baffle discs for the 80mm F15. I tried the focuser you gave me after turning the down the flange a little and found that one tube was 50mm too short the other 50mm too long. SO I will be cutting the tube this week and painting the insides once the baffles a made. I will build the Carton OTA first.
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Post by bn1777 on Oct 29, 2013 5:48:12 GMT -5
AHHH! progress , looking good , I love it and keep up the good work Matt and lots more photos please .
I am heading your way slowly , I will PM you via IIS .
Looking very nice at this stage Matt , well done so far . It's going to be white ? .... aint it ? Oh yes 'knife edge' should not be critical if the inside is well blackened and the baffles are well placed .
Brian.
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Post by boomboom on Oct 30, 2013 6:17:19 GMT -5
Not much progress but I have started a thread on CN called 150mm f12 Refractor Build. I did put the objective onto a plank and put the focuser down the other end for working out the tube length and to get a look through the lens. Here is a pic... Very nice view of the trees. Not much CA at all and none to be seen to my eye with an ES 28mm 68º eyepiece, which hits the sweet spot with exit pupil in this scope. Very happy indeed. I'm going to make the rear cell out of aluminium with push pull screws like the objective, which will mean a bit of cutting and filing by hand. I have had two wooden ones split. I guess there isn't enough wood left with the 152mm tube. That seems to be the biggest hurdle to get over. Brian the scope will be white as much as I like black. I want to get the tube cut so I can paint it and let it cure for a month before putting rings etc on it. Telescope making is a brilliant hobby.... Matt
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Post by bn1777 on Oct 30, 2013 23:15:16 GMT -5
You are right about that Matt , telescope making is great fun . Keep up the good work . Hope to see you and your build in the flesh soon . Brian.
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Post by boomboom on Nov 5, 2013 20:37:04 GMT -5
At long last gone back to my usual routine of no routine and working nights only....yehaaaa. A bit more on the focuser end. I have decided that after splitting 2 wooden focuser holders, for want of a better word, to make the things out of Aluminium plate. Great...which meant a lot of drilling for which I specially got a drill press and a lot (4-5 hours) of hand filing. The focuser will still be a push pull type which needs to be done. Plate thickness is 12mm and 6mm each. Here are some pics... The thin aluminium ring is to cover the end of the tube so it looks nice and neat. When it's on the tube I'll sand down the rough edges. The wooden ring is to be screwed inside the tube, and the rest will be bolted down to that. It just might work that the tube etc is straight and none of this will be needed! Out of the wooden ring are 3 threaded rods with baffles attached. Yet to determine the placing of these 5 baffles so shortly back to the drawing board for the ray trace. Beautifully sunny here today I should be outside with the 'ol f8 looking at the Sun, but telescope making is more fun Matt
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Post by bn1777 on Nov 5, 2013 21:27:39 GMT -5
Looking good Matt. Its a shit of a job making flanges by hand , but a little advice here if you want it on making these flange plates by hand .
Drill a centre hole 6mm after you have marked the outer hole diameter out with dividers and don't cut the inner section out yet !!!! , drill the outer diameter out as you have done and rough it down with a 4 inch grinder to within 1mm or so of the scribed outer line ( alimimium grinding discs only ! , from Bunnings ) then put a 65mm long x 6mm bolt thru the centre hole and double nut it , put the threaded end into the drill press's chuck hard against the nut up and tighten it onto the bolts thread sticking out.
Start the drill in slow speed 50rpm and clamp a G-Clamp to the bed as a rest and with the disc turning slowly hold the file against the rough circle you ground and if you go slow it will end up a fairly round circle with the drill doing the work .
Remove from drill and remove the bolt . Then use a hole saw to cut the inner hole out at 50 rpm ( Bunnings again ) with the disk clamped solidly on a piece of 1 inch ply to the bed , use kerosene as a lube on aluminium ( its the best ), sparingly and it will cut a true circle using the 6mm hole as a guide . Keep the cut cool and it will cut the inner hole out like butter .
I also think the extra alloy at the focuser end will help move the point of balance of the OTA further up making the eyepiece a little higher in use .
Keep up the good work , and photos . Brian.
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Post by boomboom on Nov 5, 2013 23:29:25 GMT -5
Hi Brian,
Mate, thanks for the advice. Sort of what I did with the 12mm flange but as my brain ain't quite up to speed today, the centre section of the 6mm outside plate has been cut out already, as you can see. At least it's 6mm and so easy to grind down compared to the 12mm. The focuser has the push pull screws done, ready to go into the tube.
A good day really as I spent 1 hour just me, a hacksaw and a 2.2m long bit of tube that is now in 2 sections. The tube for the scope is cut…1530mm long with a bit of a margin at the objective end should I need to go longer. Maths is not my thing but I did do the measure many times cut once approach. My cut end is better, squarer, than the metal shop too! Will load pics of that operation soon.
Next it's the baffle placement and drill holes in the tube for focuser flange and objective ends.
Matt
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Post by bn1777 on Nov 6, 2013 19:00:13 GMT -5
Yea Ha , great progress Matt . Keep at it . Brian.
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Post by bn1777 on Nov 6, 2013 19:02:04 GMT -5
Yea Ha , great progress Matt . Keep at it . Just one thing , it pays to check how square the cut is from the factory , sometimes they can be miles out of square . Brian.
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Post by boomboom on Nov 7, 2013 5:18:39 GMT -5
Some more photos. Getting ready to cut the tube and the cut Good one except I goofed the measurments somehow and need to cut 20mm more off....
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Post by boomboom on Nov 7, 2013 5:27:36 GMT -5
And the focus end...all coming together. Lots of screws and bolts out this end as the focuser is a push pull thing like the objective. The plan and reality thus far And the focuser with diagonal just for a sneak preview, still have to grind down the rear plate Inside is three baffles held in place and attached to the inside focuser plate with threaded rods. Looks good inside with no vignetting as far as I can tell. Can see the three Objective spacers but not the tube. Not long now.... Matt
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Post by bn1777 on Nov 8, 2013 21:24:21 GMT -5
Looking good Matt its starting to look like a scope now , that cut looks nice and square , well done . At least it was cut 20mm long , easy to fix and I like the baffle arrangement , you are powering it mate , cant wait for first light report . Brian.
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Post by boomboom on Nov 10, 2013 19:16:57 GMT -5
Well here it is on the mount perfectly balanced as it is and a whole lot lighter than my Synta f8, mostly due to a lack of finders etc I think. Seems the NEQ6 will handle this OK. Not the tripod I'll use, and ready for a star or two to look at. Still needs a dew shield and finderscope and a Losmandy saddle and paint but nearly there. The objective cell is held on with 6 M5 bolts threaded on the OTA nice and solid. Along the way I discovered the tube isn't quite round, a bit of a flat spot but no worries. Put a laser into the focuser and a bit of adjustment down at the focuser end had the beam smack bang in the middle....beautiful. I thought at the beginning this was going to be hard but I'm surprised how straight forward the process was. Wouldn't say it was easy but not hard either. Anyone thinking of doing it should jump right in. Can't wait to point this one up at the stars and will post a first light report when I do...... Matt
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