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sammak127

Skywatcher Mak 127 - electric focus device - D.I.Y. with pics!

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I really enjoy the Mak 127, it's a great little telescope. The Supatrak mount that it comes with is not quite so good though. I found that it was really hard to get a good focus, because any touching of the scope would result in such crazy vibrations that you couldn't see if it was in focus or not anyway.

So I designed this little machine to help.
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It is a gear motor from ebay (12V DC - HIGH TORQUE High power - Reversable Electric Motor 15 RPM & Gear-Box)
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I designed a little bracket that slots into the gap between the dovetail bar and the telescope.
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Which I then cut out of a bit of 2mm Aluminium and attached to the motor.
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The brown plastic is an air hardening plastic called Sugru, which I just moulded around the bit I wanted to protect from dew.

The timing belt and pulleys were tricky to work out. I decided to put a large pulley over the existing brass focus knob(which is under the rubber cover) because it also holds onto a piece that goes inside the scope and all hell seemed about to break loose when I loosed the allen bolts holding it on.. also to retain resale value in case I can ever afford to upgrade.
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the speed is controlled by a motor regulator. (12V-24V 3A DC Motor Speed Regulator Controller Switch Control) which I have temporarily (probably permanently) placed in a old plastic case. The case has 5 cable going in and out. 12v dc in, 12v dc out, connection to motor and then the controller.

The controller is taped to the back of the Supatrak controller so I can use them together. The cables of the two controllers are taped together.
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It works a treat. Inside the handset is a little potentiometer to vary the speed, and a switch to change direction. You can do really fine adjustments without any vibrations. It can also move quite fast to swap focus between eyepieces or a DSLR attached instead. But equally the timing belt comes off fairly easily for manual focussing.

I could try and provide a more detailed plan if anyone thought that would be interesting or useful.

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That's very similar to the way I did mine, though I used an existing Skywatcher focuser motor drive.

James

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I must get motivated and do this mod to my 150 pro

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