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Azimuth Setting Circle Modification


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A couple of people have asked me about putting Azimuth circles on your dobsonian base, this is how I did it on my old 16" Meade Lightbridge,

The base measures 800mm, so I had a degree circle printed out on A0 paper at 795mm in diameter.

I used this website to get the template


/>http://settingcircles.robertwillett.com:8000/

I then cut out some 3mm hardboard at 795mm as well and glued the circle to it.

I then coated both sides in sticky back plastic to waterproof it.

I then screwed through the teflon spacers and secured the degree circle to the dob ground board.

I then placed the bearing and plates on top of this.

I then had to make up some sort of indicator so I cut a piece of flat metal and drilled two holes in the ends and mounted this to the upper board with some bolts, spacers and inserts.

The indicator is made up of two cabinet magnets superglued together and a hole drilled in the middle to accomodate the indicator. I then painted the indicator red and the metal plate black.

The magnet now sits on top of the plate at the desired position.

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Here are some links for electronic angle gauges.

I have used Axeminster power tools, but not any of the others.

This one is handy as it has a built in level to calibrate the gauge.

http://www.ebay.co.u...5#ht_4115wt_980

One without a level, but then you need to get a level to zero it.http://www.ebay.co.u...3#ht_2662wt_980

And here's a rotary one if you don't want a setting circle. You will need a M10 bolt machining to accept the 6mm encoder shaft, this is what imparts the motion for the encoder to read.

http://www.ebay.co.u...f#ht_3451wt_980

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Here are some links for electronic angle gauges.

I have used Axeminster power tools, but not any of the others.

This one is handy as it has a built in level to calibrate the gauge.

http://www.ebay.co.u...5#ht_4115wt_980

One without a level, but then you need to get a level to zero it.http://www.ebay.co.u...3#ht_2662wt_980

And here's a rotary one if you don't want a setting circle. You will need a M10 bolt machining to accept the 6mm encoder shaft, this is what imparts the motion for the encoder to read.

http://www.ebay.co.u...f#ht_3451wt_980

Awesome! Thanks Martyn :)

Felix

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  • 2 months later...

Looking to get this done at some point in the near future, just have one really daft question.

Does 0/360 degrees need to point north?

Don't want to make a daft mistake which stops me from finding anything :(

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In an ideal world Ron is correct but it's not that important. If your zero degrees was at North then the pointer would be at the front of your scope, a little bit awkward to view. So by placing the zero degrees at the side of your scope, the same side as your focuser makes it a lot easier. So in theory it's 90° out but this does not matter as long as you have Polaris in your eyepiece view when you set zero degrees with your pointer.

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Yes Pat you should try and laminate it, problem is finding a laminator that laminates A0 size, so I covered mine in sticky back plastic, it worked really well, and in the 3 years I had the dob, never leaked once.

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Nice could you not have cut a circle out make sure to water proof the rough edge,it looks great I love shed DIY

Great job mate what bearing is that

Not sure Pat what bearing Mick has used but I have used a 12" lazy Susan bearing on my dob base.

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I still have the standard one in might look in to upgrade in mine

I did a guide with pictures, places to buy stuff, prices etc in the guides section. May help you out.

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  • 2 weeks later...

Does anybody know of anywhere that can laminate and scale up a setting circle?

I have the setting circle on a PDF file on my pc but I dont have the ability to print and laminate to the size of my dob's base.

Would Hobby Craft or any where like that be able to help?

Cheers chaps.

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Try Staples (office supplies) - they used to do it for under £20 but it may be a little more these days. :)

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