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Equatorial Platform for Dobsonian Telescopes


Moonshane
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quick update.

  • undercoated and painted all round - used matt black paint which is good but a mistake as it shows every mark every time you touch it - but hey, it's just a water seal really. use satin next time I think or maybe coat with a matt varnish if I can be mithered.
  • added and tested most of the wiring and switches. the two toggle switches control power to fan / EQP and then the other controls the two motors on reverse and one forward.
  • I have also added the capacity to charge the battery in situ - saves messing about - through phono sockets.
  • have added a small bubble level to assist with leveling (obviously!).

I STILL(!!) await my pwm controller and when this comes I will tidy the wiring up and connect everything. I also await my machined parts for the drive rod and again this will be a doddle to fit together once it's all here.

hoping for a test run this weekend if it works out.

looks OK, lets hope the blummin thing works!

I suspect that vibration and noise from the forward motor will be a 'challenge' to overcome but I have some ideas for this once it is tracking at the right pace.

here's some pics

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Hi Moonshane , It is possible that either of these PWM devices from Maplin might cut the mustard ( and you have a few shops in the area with stock if you want to progress without the postie !). The two items are RN41U and WC76H . I have the panel mount one (waiting to be used for a focusser ). Hope this is a help . The other device is a 'screwdriver set' one so probably less useful ?

Edited by LeoLion
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Very professional looking job there Shane but I suspect with such a matt black finish your gona have a few stubbed Piggy's on those corners :(

cheers Nick - I have planned to add (at the end) a run of either white paint of white insulation tape (probably the latter) to try and reduce my pain! may also add a red led under the top to accent the shape but not sure yet.

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Looks good Shane.

It's taking time to get the PWM through the post though. Coming from out China way?

cheers Sean, yes China - should have ordered it earlier really. will hopefully be here soon - probably affected by Chinese NY.

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Hi Moonshane , It is possible that either of these PWM devices from Maplin might cut the mustard ( and you have a few shops in the area with stock if you want to progress without the postie !). The two items are RN41U and WC76H . I have the panel mount one (waiting to be used for a focusser ). Hope this is a help . The other device is a 'screwdriver set' one so probably less useful ?

cheers for the pointer. this might actually be OK. I have asked them about the pulse rate as if it's too low it will feed through as vibration in the motor at low speeds.

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update

the PWM controller arrived today - yippee! all soldered in and tested the motors, works a treat.

a bit like spaghetti junction currently as I have made it a little more complex than it needed to be for convenience as I have an additional fan and charging point so I don't ever really need to remove the 12v 7ah battery. looks a lot better with the lid on!

I am now just waiting for the drilled and tapped stainless parts and hopefully will get these this weekend. I can then make my linkage to the top board and set up the drive rod and aim for a trial run.

the motor noise and vibration seems to have reduced rather than increased with lower speed (the opposite of what I expected) so this is a bonus too.

I'll have the trial run before deciding whether to make insulated covers for the motors or not. might just need a straight box.

note that I used blue wires for the reverse circuit and brown for the forward circuit to aid location of any faults in the future (hopefully there won't be any though!).

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cheers Porl - I am just in the middle of making some small boxes to cover the motors to reduce noise (it's not too bad but I'd like 'silent') and also protect them from dew etc.

let's hope it all works when I put a scope on it!

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cheers Porl - I am just in the middle of making some small boxes to cover the motors to reduce noise (it's not too bad but I'd like 'silent') and also protect them from dew etc.

let's hope it all works when I put a scope on it!

Fancy making some of them boxes for my CG5-GT while your at it. They will probably have to be made of lead though :(

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WELL!! I am officially excited. I have put everything together and it has my 6" scope on and is moving well. Just need to adjust the speed to track properly but there seems no reason it won't be spot on.

I'll try my 12" too a little later and I am hopeful this will work OK too.

I'll post some pics when I get a chance.

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cheers mate

the 12" is on and 'tracking' although I'll reserve judgment until I actually look at something and it tracks

I fear the next challenge will be vibration as I can 'hear' the motor by putting my ear to the tube (probably more feel than hear). let's hope it's not visible in the EP.

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the 12" has been quite happy tracking to and fro for a while so it seems ok. just need a target now to check it works in the real world! must remember not to try Polaris.......

Edited by Moonshane
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well it certainly tracks. I reckon though that I only get maybe 10 minutes at 250x before it drifts out of view. still a lot better than previously. I'll report back again later when the moon's up (here - behind houses currently).

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