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colinheath

Skywatcher Mak 127 electric focuser

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Hello All,

Well had a great welcome in the welcome lounge, thanks very much:D

OK I have had a little time today to start my electric focuser mod. Everything except servo will be home made. I am fortunate enough to have access to lathe and milling machine so making all parts from scratch.

I have attached a picture of the fucuser pulley made in aluminium. The servo mount will be ali also and will just slide into place with no drilling required (well that's the plan)

post-16535-133877371616_thumb.jpg

post-16535-133877371621_thumb.jpg

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Colin, looking good! Also have a 127 Mak, so will be watching with interest.

Keeps us posted mate.

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Will do James. I hope to get a little more done this weekend. I have all the electronic bits on order for tomorrow so should be finished fairly soon.

I was going for the battery free design which uses one servo to drive another. I found i couldn't get smooth drive below a certain speed though so went with battery power for now.

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Good, good. Yeah tried the servo/servo way once, was to be fitted to SW200 scope, but like you say, couldn't get that smoothness at slow speed. Did do a 12v version, but never got it finished. Good luck with it at the weekend.

Do a search on forum for other topics on electric focusers, might help??

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OK parts are here for the control box so all set if i get time to finish the focuser this weekend:D

I have just aquired a nice piece of 4" stainless steel pipe to build a pier for the scope. Just have to convince her indoors how nice it will look in the garden;)

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OK got the mount for servo finished and switches mounted in hand control box. Just need to solder up and then ready for test. Will probably be weekend before I get chance to finish. i will get some pictures later though of progress.

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Same here Colin. Pics would be great.

Going to try this on my month old 127 az goto. If my soldering skills are up to it. Most people call it soldering. I can only manage "blobbing" hot lead around. And thats on a good day. HeHe.

Clear skies.

Dave.

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Thanks for the reminder:D

Here are the pics. not the best as taken with phone. the ali block has dovetail machined on back so slides straight onto original mount bracket. servo is bolted into this. will have coiled cable between.

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Oh huge clunky bolt has been replaced with grub screw now;) and it will all be cleaned up when finished. Maybe even anodise it:D

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Really excellent work Colin.

I can assure you now I can't approach that level of professional workmanship. I will keep on watching your progress though.

I can see it's not for the faint hearted to attempt.

Excellent.

Dave.

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I only went to such levels just because I have the kit available to do it. It can be done with a simple bracket that could be fitted under dovetail and just clamped. reason being the servo is very light so doesnt require anything near as complex as I have done:)

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Colin, that look's fantastic mate!! Really good idea of mounting the the bracket on the dovetail! :) Has defo got me thinking about following in your footsteps :cool:.

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Thanks James, I was worried about clearance viewing over head but clears fine so all good:) I hope to finish this weekend if work doesn't prevent me so will get the finished pics up:D

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OK I think I have it all finished (for now)

I had a little plastic pulley ready made on the servo but couldn't get any grip on belt. I then made an aluminium pulley and this works much better:D

It all works now and gives good control on speed etc with no apparent vibration of scope although the proof will be in the viewing.

If i will change anything it will be the control box as I made a bit of hash of the cutouts etc and switches aren't as level as should be. I have been making panels for years but never used square switch bodies. will be round next time;)

Here are the pictures and will get a vid posted up later of operation

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post-16535-133877373984_thumb.jpg

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Have you modified the servo so that it can rotate continuously Colin or did you buy it already modded?

--

Martyn

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Yes I modified the servo for continuous rotation. was a very easy with a stanley knife to just cut off tang on plastic gear then just remove control electonics:D

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OK tried the focuser last night and it made life very easy:) Much better to focus and was lots better with imaging. My imaging is terrible but the focusing was fine:p I did notice some vibration if i wasn't careful with lead but apart from that it's good.

Next mod is going to be a decent pier mount for the scope. I was going for one sunk in ground but the boss indoors doesn't seem keen on the idea;) So i will build a base and concrete into ground then just have to slide it onto studs.

I will be using 4" stainless steel pipe with 8" x 1.5" disk on bottom also in stainless.

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Colin, job well done mate :cool:. Will have to get cracking on makeing one myself :).

And keep us posted on the pier!

James

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Hi Colin.

A first class job. You put a lot of retail producers to shame.

Is it possible to put up a circuit diagram. I have lots of servos hanging around in my other guise as a RC helicopter flyer and could knock myself up a second rate copy of yours. It'll give me something constructive to do in the shed 'till the clouds subside.

I'll also be keeping a close eye on your forth coming pier. Welding stainless steel. That sounds difficult!

Clear skies.

Dave.

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Colin, job well done mate :cool:. Will have to get cracking on makeing one myself :).

And keep us posted on the pier!

James

Thanks James, Will start a thread when I build the pier:D I have already sowed the seed with the boss indoors and she is coming round;)

Hi Colin.

A first class job. You put a lot of retail producers to shame.

Is it possible to put up a circuit diagram. I have lots of servos hanging around in my other guise as a RC helicopter flyer and could knock myself up a second rate copy of yours. It'll give me something constructive to do in the shed 'till the clouds subside.

I'll also be keeping a close eye on your forth coming pier. Welding stainless steel. That sounds difficult!

Clear skies.

Dave.

Thanks for the kind words Dave:D I will knock up a diagram and post it up. maybe a few days though as really busy at present. Please feel free to bump the thread as a reminder;)

Stainless steel welding is fine with a little practice. i work in the food industry as an engineer so have had lots of experience. I prefer welding stainless to any other metal now.

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